Distal Embolization in Grade V Splenic Injury

Clinical Results of Distal Embolization in Grade V Splenic Injury: Four-Year Experience from a Single Regional Trauma Center

Clinical question
In patients with grade-V blunt splenic injury (BSI) according to the American Association for the Surgery of Trauma (AAST), does distal splenic artery embolization (SAE) confer non-operative clinical success and splenic salvage?

Take-away point
Distal SAE is safe for patients with grade-V BSI and effective for splenic salvage

Reference
Lee, Rang, Chang Ho Jeon, Chang Won Kim, Hoon Kwon, Jae Hun Kim, Hohyun Kim, Sung Jin Park, Gil Hwan Kim, and Chan Yong Park. “Clinical Results of Distal Embolization in Grade V Splenic Injury: Four-Year Experience from a Single Regional Trauma Center.” Journal of Vascular and Interventional Radiology 31, no. 10 (October 1, 2020): 1570-1577.e2.

Click here for abstract

Study design
Single-institution, retrospective cohort study consisting of 42 patients who underwent SAE for grade V BSI

Funding source
Biomedical Research Institute Grant 2017B010

Setting
Pusan National University Hospital, Busan, Republic of Korea.




Figure. Visual Synopsis of results

Summary

Blunt splenic injury (BSI) is a common and potentially life-threatening sequelae of abdominal trauma. Timely evaluation and severity grading using an organ injury scale published in 2008 (revised 2018) by the American Association for the Surgery of Trauma (AAST) is widely used to guide management options consisting of observation, splenic arterial embolization (SAE), or surgical resection. Based on computed tomography (CT) scan or intraoperative exploratory findings, patients are categorized as low-grade (I-III) or high-grade (IV-V). Guidelines for management of BSI vary per institution. Operative management is generally reserved for patients who have high-grade BSI or hemodynamic instability while the use of SAE for either cohort remains controversial. Thus, the authors conducted a retrospective cohort of 42 patients with grade-V BSI who underwent distal SAE to evaluate technical and clinical success, splenic salvage rates, and complications.

Pre-procedure CT scans of 88 patients who underwent distal SAE at a single trauma center were reviewed and 42 patients were categorized as grade-V using the revised guidelines by the AAST. Patients were further stratified based on hemodynamic stability with hemodynamically unstable patients defined as systolic blood pressure < 90 mmHg or systolic blood pressure > 90 mmHg requiring vasopressors and/or who had base excess >-5 mmol/L at admission and/or shock index >1 and/or transfusion of at least 4–6 units of packed red blood cells in the first 24 hours. 23 subjects were hemodynamically unstable and 19 patients were hemodynamically stable. Male to female ratio was 35 to 7 and average age was 47 years.

Technical success was defined as cession of bleeding while performing splenic angiography and clinical success was defined as successful SAE without rebleeding or splenectomy. If a second SAE was required for rebleeding then secondary clinical success was determined by need for splenectomy after second SAE. Splenic salvage was defined as viable splenic tissue on follow-up CT. Follow-up CT was performed retrospectively at 3, 7, and 30 days post-SAE. Major complications as determined by the Society of Interventional radiology included any complication that required extended hospitalization or advanced care leading to permanent adverse effects or death.

Technical success of distal embolization was achieved in all patients. Clinical success was achieved in 80.9% of patients (n=34). Secondary clinical success was achieved at 88.1% (n=37) as 3 patients required a second embolization. 4 patients required post-SAE splenectomy and 2 patients suffered from major adverse complications. One of these patients died of acute respiratory distress syndrome and the other patient developed a splenic abscess at 22 days post-SAE. Splenic salvage was achieved at 85.7% (n=36). There was no significant difference seen in primary clinical success (p = .709) or splenic salvage rates (p = .197) between hemodynamically stable and unstable patients.

The authors concluded that distal SAE is safe for patients with grade-V BSI who are hemodynamically stable or unstable. However, for unstable patients, they discuss that distal SAE may be better suited for patients who respond to general resuscitation efforts prior to intervention. A previous consensus study had concluded that time to intervention for nonoperative management of BSI should be < 60 minutes. The authors propose that the high success rates in the current study may be attributed to its short time to intervention (mean = 91 minutes) which was shorter than similar previous studies with less successful clinical outcomes (mean = 171 minutes).

Commentary

This study consisted a small sample size (n=42) at a single institution over a 5-year period. Extending the study period to an earlier date may increase sample size and improve study power. This study had a median follow-up period of 247 days and additional longitudinal follow-up is necessary to determine NOM failure rates requiring splenectomy. Also, this study only evaluated splenic salvage via CT scan as a secondary outcome. In addition to splenic salvage, previous retrospective studies have included secondary endpoints such as splenic function determined by immunoglobulin and/or T-cell subset levels. Including more characteristics of splenic function may provide more convincing evidence that SAE has advantages over operative management in BSI.

Post Authors:

Daniel Yoakum, RMC Class of 2022
@DanYoakum 

David M. Tabriz, Assistant Prof VIR RUMC
@DrDaveTabriz

静脉生物力学特性和泊松效应

静脉血管成形术和支架植入术的生物力学特性 : 

泊松效应的潜在影响

目的

表征静脉血管成形术和支架植入术中产生的泊松效应，并陈述其潜在影响，用于指导未来静脉专用的支架与疗法设计。 

Click here for abstract 

Ningcheng Li, MD, MS, Francine Mendoza, BS, Sandra Rugonyi, PhD, Khashayar Farsad, MD, PhD, John A. Kaufman, MD, Younes Jahangiri, MD, Barry T. Uchida, BS, Craig Bonsignore, BS, Ramsey Al-Hakim, MD. Journal of Vascular and Interventional Radiology (JVIR), Volume 31, Issue 8, 1348-1356.

材料和方法

应用已建立的静脉狭窄模型，对3只成年猪进行活体血管成形术和支架置入术。以铁颗粒作内壁标记在介入过程中实现实时荧光透视，观察血管壁活动。使用ADINA软件（版本9.5）创建具有动脉和静脉生物力学特性的血管有限元计算模型，从而来比较血管对径向膨胀的不同反应。

结果

在具有铁粒子内壁标记的静脉狭窄动物活体模型中，血管成形术和支架置入证明纵向缩短与距成形球囊中心的距离成正比（R2 = 0.87）; 相邻节段变窄与狭窄的节段术后直径增加同成正比（R2 = 0.89）。有限元计算分析表明，在静脉与动脉相比中，由于纵向杨氏模量较大，静脉中的泊松效应比在动脉中明显（线性回归系数斜率比较，动脉斜率0.033，R2 = 0.9789；静脉斜率0.204，R2 = 0.9975； P < .0001）。

结论

在临床静脉血管成形术和支架置入术中观察到的相邻节段变窄，是由泊松效应及其相应的径向膨胀力纵向重新分布而导致。由于血管独特的生物力学特性，静脉中泊松效应比在动脉中增加。此结果可能会影响以后静脉介入支架与疗法的设计。

摘要作者

李宁成 医学博士 生物工程硕士

放射介入住院医师

俄勒冈健康与科学大学

@NingchengLi

Endovascular and Surgical Treatments for Fibroids

Utilization of Endovascular and Surgical Treatments for Symptomatic Uterine Leiomyomas: A Population Health Perspective

Clinical question
What are the outcomes of a population-level analysis of surgical and endovascular interventions for symptomatic uterine leiomyomas in the outpatient setting?

Take away point
Uterine Artery Embolization (UAE) may be an underutilized and a lower cost alternative than surgical interventions. Future research should focus on the role of UAE and fertility preservation.

Reference
Utilization of Endovascular and Surgical Treatments for Symptomatic Uterine Leiomyomas: A Population Health Perspective. Wang, C.. et al. Journal of Vascular and Interventional Radiology, Volume 31, Issue 10, 1552-1559.

Click here for abstract

Study design
Retrospective review using the Healthcare Cost and Utilization Project (HCUP) databases of patients treated in the outpatient setting for symptomatic leiomyomas in California and Florida.

Funding source
No funding

Setting
Hospital-owned and non-hospital owned outpatient settings in California and Florida

Summary

The three main treatments for symptomatic leiomyomas include: hysterectomy, myomectomy and uterine artery embolization. Surgical intervention, whether definitive treatment with hysterectomy or fertility-preserving myomectomy, are the most common interventions for leiomyoma treatment. Uterine artery embolization has also been established as an effective minimally invasive treatment option, though is used less frequently. Given the lack of information regarding the utilization of these procedures, this paper addresses the association between different treatment options and various patient characteristics.

Data was gathered from the Healthcare Cost and Utilization Project (HCUP) database for all outpatient hospital encounters for symptomatic uterine leiomyomata in California (2005-2011) and Florida (2005-2014) (n=227,489). These states were chosen as they have large populations, socioeconomic diversity, geographic distribution and a mixture of urban and rural populations. They analyzed patient characteristics and common comorbidities including: age, ethnicity, hypertension, diabetes, renal insufficiency, obesity, smoking, chronic obstructive pulmonary disease, and congestive heart failure. They also noted the hospital stay duration and costs.

Of the total 227,489 patients with uterine leiomyomata, nearly 40% (n=90,800) underwent an intervention. Hysterectomy was the most common intervention (73%), followed by myomectomy (19%) and UAE (8%). Over time the proportion of patients receiving a hysterectomy increased—and laparoscopic (versus open) hysterectomy accounted for the greatest proportion. Given hysterectomy is a definitive treatment, it was later performed in 4.1% of those who underwent myomectomy and 3.5% of patients who underwent UAE. Patients who underwent myomectomy were younger and had fewer comorbidities than those who underwent hysterectomy or UAE. Those receiving UAE instead of myomectomy or hysterectomy were older and more likely to have congestive heart failure, renal failure, and hypertension. UAE is performed more frequently in those with comorbidities, as it is often safer to avoid general anesthesia or an invasive surgery. The hospital stay duration varied between the groups with hysterectomy having a significantly greater length of stay (0.5 d; range 0-3 d). No difference between length of stay was seen between myomectomy (0.2 d; range 0-3 d) and UAE (0.3 d; range 0-3 d). Hysterectomy and myomectomy were also significantly higher in cost than UAE ($5,409 and $6,318 vs $3,772, respectively).

Previous research has demonstrated lower cost, shorter hospital length of stay and faster return to activities in UAE compared to invasive surgical interventions. Despite these findings UAE is not utilized as frequently. Given the large portion of child-bearing aged women undergoing myomectomy, the authors argue a part of this difference may be due to the lack of definitive research regarding fertility preservation.

Commentary

This study helps underscore many differences between endovascular and surgical treatments for symptomatic leiomyomas. It also helps support existing findings in research, while shedding light on new areas such as patient comorbidities and prevalence of particular interventions. Although this is a retrospective review, the large and diverse sample size helps give the study power. The study notes that UAE is more cost effective, has a shorter recovery time and is generally regarded as safer for those with significant comorbidities. However, given the lack of definitive research on fertility, it is often not performed in women of childbearing age. Further research into UAE and fertility may help broaden its use if it is found to be a fertility-preserving alternative. Lastly, the article mentions that the cost for the intervention was based on the initial encounter and did not include any subsequent treatments. They discuss that the subsequent treatments have a long time interval between them and that repeat intervention rate is low. Clarity into the specific numbers would help strengthen the cost differences between the interventions. Overall, this study helps shed light on the current interventions, patient populations and future challenges of the treatment of symptomatic leiomyomas.

Post Author
Marissa Stumbras, MD
Interventional Radiology Resident, PGY2
Oregon Health & Science University
@MarissaStumbras

Double-Needle Lavage for Treating Thyroid Cystic Nodules

Double-Needle Lavage for Effective Treatment of Difficult-Aspiration Thyroid Cystic Nodules: A Single-Center Controlled Trial

Clinical question
How does the safety and efficacy of a double-needle lavage (DNL) compare to single-needle aspiration (SNA) in the treatment of thyroid cystic nodules?

Take-away point
DNL demonstrated significantly improved efficacy in terms of material extraction rate and nodule volume reduction compared to SNA. Neither the DNL or SNA group experienced adverse events.

Reference
Xiaoyin T, Ping L, Bingwei L, et al. Double-Needle Lavage for Effective Treatment of
Difficult-Aspiration Thyroid Cystic Nodules: A Single-Center Controlled Trial. J Vasc Interv Radiol. 2020;31(10):1675-1681.

Click here for abstract

Study design
Randomized Controlled Trial

Funding source
Self-funded or unfunded

Setting
Single institution, Renji Hospital, School of Medicine, Shanghai Jiaotong University





Figure. Diagram and ultrasound image of the DNL method. (a) Diagram of the method used in the DNL group; (b) preaspiration; (c) 2 needles inserted in the same ultrasonic plane; (d) immediately postaspiration.

Summary 

Thyroid nodules are highly prevalent in the general population. Cystic nodules comprise a significant proportion of these. While most cystic thyroid nodules are asymptomatic and benign, symptomatic or malignant cystic nodules warrant treatment. Percutaneous treatment modalities for cystic nodules generally require removal of the cystic component, which can often be complicated by needle obstruction due to complex cyst contents when using a single-needle aspiration (SNA) method. The double-needle lavage (DNL) method seeks to solve this problem by inserting 2 needles into a difficult-aspiration cystic nodule to achieve successful aspiration.

In this single-center randomized controlled trial, 100 patients being treated for thyroid cysts that were identified as having difficult aspiration on initial SNA were randomized to either aspiration via the standard SNA method or the experimental DNL method. Difficult aspiration was defined as either a) complete aspiration not achieved with a single aspiration or b) aspiration of ≤0.5 mL during SNA. Inclusion criteria included symptomatic, ≥2cm fine needle aspiration-confirmed cystic thyroid nodule with absence of malignant tumors. Exclusion criteria included history of cervical radiation, family history of thyroid cancer, severe heart, lung kidney immune system disease, or abnormal coagulation.

40 patients were initially randomized to the SNA group and 60 to the DNL group. The SNA technique involved inserting a single needle into the center of the cystic nodule and aspirating the contents with intermittent sterile water flushes to assist as needed. The DNL technique involved inserting 2 needles simultaneously into the cystic nodule and aspirating with one needle while simultaneously flushing sterile water into the nodule with the other needle. The DNL patients were randomized into 2 subgroups: one with needles both inserted into the center of the cyst in the same ultrasound plane and the other with needles inserted into opposite poles of the cyst. Safety was assessed by measuring complication rates of each technique during the trial. Efficacy was evaluated by both the material extraction rate and reduction rate of total nodule volume after treatment. Operating time of the treatment was also compared.

10 of the 40 patients initially randomized to the SNA group were unable to have more than 1 mL aspirated after 10 minutes of flushing and aspiration attempts; they all opted to switch to the DNL group for further treatment. At the end of the trail, 30 patients underwent SNA and 70 patients underwent DNL. 35 patients each were randomized into the two different DNL technique groups. Volume reduction rate in the DNL group was 95.62 ± 3.66% versus 87.54 ± 7.84% for the SNA group (P < .001). Material extraction rate in the DNL group was 98.45 ± 1.74% versus 91 ± 6.51% in the SNA group (P <.001). DNL procedures took less time than SNA procedures (5.77 ± 1.44 minutes for DNL versus 12.47 ± 3.71 minutes for SNA, P <.001). When both different types of DNL technique were compared, aspiration with both needles at opposite poles yielded lower post-procedure cyst volumes compared to aspiration with both needles in plane at the center of the cyst (0.07 ± 0.08 mL versus 0.22 ± 0.4 mL, P < .05). This did not correspond to a significant difference in material extraction rates except in nodules ≥3 cm (98.71 ± 1.17% versus 96.58 ± 2.35% vs P < .01).

No adverse events or complications, including bleeding, infection, or recurrent laryngeal nerve injury, were noted during the trial.

Commentary

This prospective trial demonstrated the efficacy of a novel technique, DNL, for the aspiration of cystic nodules that are initially found to be difficult to aspirate. The technique not only proved better at reducing cyst volumes but also proved successful in cases of initial treatment failure with SNA technique. The investigators also evaluated two different DNL techniques and found that inserting the aspiration needles at opposite poles of the cyst may improve material removal, especially in cysts ≥3 cm. Additionally, neither DNL or SNA resulted in adverse events during the trial. While this speaks to the safe nature of both techniques, larger investigations across multiple centers may establish a more comprehensive risk profile. While the novel DNL technique seems promising, this trial did not evaluate clinical significance of the improved material extraction and volume reduction rates. While only symptomatic nodules included in the trial, follow-up data was not captured. Larger multicenter trials that capture symptom reduction in addition to the valuable volumetric data collected herein will help to determine superiority of this promising new aspiration technique.

Post Author
Jared Edwards, MD
General Surgery Intern (PGY-1)
Department of General Surgery
Naval Medical Center San Diego, San Diego, CA

@JaredRayEdwards

Same-Day Holmium-166 Simulation and Treatment of Hepatic Metastases

Evaluation of the Safety and Feasibility of Same-Day Holmium-166-Radioembolization Simulation and Treatment of Hepatic Metastases 

Clinical question
Is same day Holmium-166 radioembolization simulation and treatment feasible and safe for the treatment of hepatic metastases?

Take away point
Same day Holmium-166 radioembolization simulation and treatment is safe and feasible for a select patient population.

Reference
van Roekel, C., N. I. Harlianto, A. J. A. T. Braat, J. F. Prince, A. F. van den Hoven, R. C. G. Bruijnen, M. G. E. H. Lam and M. L. J. Smits (2020). "Evaluation of the Safety and Feasibility of Same-Day Holmium-166 -Radioembolization Simulation and Treatment of Hepatic Metastases." Journal of Vascular and Interventional Radiology 31(10): 1593-1599.

Click here for abstract

Study design
Retrospective analysis

Funding Source
None

Setting
Department of Radiology and Nuclear Medicine, University Medical Center Utrecht, Utrecht University





Figure. Example case. A 65-year-old male with neuroendocrine tumor metastases was treated with same-day 166Ho-radio- embolization. Figure (a) shows the baseline contrast-enhanced CT image with a large hypervascular metastasis in segment 6. Figure (b) shows the distribution of 166Ho-scout on SPECT/CT. Figure (c) shows the distribution of the 166Ho-treatment dose on SPECT/CT. Figure (d) shows the contrast-enhanced CT image 3 months after treatment, with evident shrinkage (see annotation) of the metastasis in segment 6.

Summary

Holmium-166 (166Ho) microspheres are an alternative to yttrium-90 (90Y) for the treatment of liver metastases. 166Ho microspheres emit both beta and gamma radiation, allowing the same particle to be used for both simulation and treatment dosing which may simplify a same-day treatment procedure.

The authors reviewed 105 patients from previous prospective 166Ho radioembolization studies (HEPAR I and II, HEPAR PLuS, and SIM) who underwent same day radioembolization treatments. The patients underwent baseline triple phase abdominal CT, preliminary simulation angiogram and 166Ho scout administration, 166Ho-SPECT/CT to determine dose distribution and extrahepatic activity, and angiography with treatment dose delivery. The median scout procedure time was 1 hour and 43 minutes. The median treatment procedure time was 1 hour 11 minutes. The median total procedure time, including simulation, imaging, and treatment, was 6 hours and 39 minutes.

The technical success rate was 88%. The treatment plan was modified in 14 cases because of extrahepatic deposition, suboptimal targeting, and unanticipated vascular anatomy. Radioembolization was cancelled in 15 cases because of extrahepatic deposition, suboptimal targeting, unanticipated vascular anatomy, and dissection. Extrahepatic deposition was identified in 5 cases with no clinical significance. Side effects were comparable to the previously established side effects of radioembolization procedures and included back pain, chest pain, abdominal pain, contrast reaction, nausea, vomiting and dyspnea. While three patients experienced minor bleeding after sheath removal, the indwelling vascular sheath did not cause any adverse events.

Commentary

The authors reviewed 105 patients from previous prospective 166Ho radioembolization studies. The 88% technical success rate shows that single day radioembolization treatment is feasible. The lack of major adverse events suggests that the procedure is safe. As the authors described, the current study is limited by the heterogenous cohort, selection bias, and the learning curve related to the treatment technique. The author’s statement that they will not use a same day treatment approach at their institution because of 166Ho dosing limitations addresses a significant limitation to same day 166Ho treatment. Nevertheless, 166Ho radioembolization presents a compelling alternative to 90Y for treating liver metastases. 166Ho’s intrinsic properties that allow the same particle to be used for both planning and dose delivery presents a unique opportunity to improve the accuracy of dose administration. While single day 166Ho radioembolization is limited to a patient population in which a pretreatment dose estimation is viable, a single day radioembolization procedure remains an important subject as it presents an opportunity to decrease time to treatment and reduce medical cost.

Post Author
Maxwell Cretcher, D.O.
Integrated Interventional Radiology Resident, PGY-4
Department of Interventional Radiology
Dotter Interventional Institute, Oregon Health and Science University
@MCretcher

Augmented Reality Informs Locoregional Therapy

Three-Dimensional Augmented Reality Visualization Informs Locoregional Therapy in a Translational Model of Hepatocellular Carcinoma

Clinical question
Is augmented reality (AR) visualization of pre-procedural magnetic resonance imaging (MRI) in 3 dimensions (3D) beneficial prior to transarterial embolization of hepatocellular carcinoma (HCC) in a preclinical rat model?

Take away point
3D AR visualization of pre-procedural imaging can reduce procedural fluoroscopy time and potentially total catheterization time. Further animal studies as well as prospective trials in human participants are warranted to evaluate the potential of AR implementation in endovascular interventions.

Reference
Three-Dimensional Augmented Reality Visualization Informs Locoregional Therapy in a Translational Model of Hepatocellular Carcinoma. Park, B.J., Perkons, N.R., Profka, E., Johnson, O., Morley, C., Appel, S., Nadolski, G.J., Hunt, S.J., Gade, T.P. Journal of Vascular and Interventional Radiology (JVIR), Volume 31, Issue 10, 1612-1618.

Click here for abstract

Study design
28 rats with diethylnitrosamine (DEN) induced HCCs larger than 5 mm were enrolled prospectively. 12 rats underwent transarterial embolization after 3D AR visualization while the other 16 rats underwent transarterial embolization with two-dimensional viewing only of the pre-procedural MRI. An additional retrospective cohort of 15 cases were later identified and combined with the non-3D-AR-visualization group to increase statistical power. Procedural metrics including fluoroscopy time, catheterization time, and radiation exposure were measured and compared.

Funding source
B.P. received grants from the National Institutes of Health (5T32EB004311), Society of Interventional Radiology Foundation, and Radiological Society of North America Research and Education Foundation. The authors thank the Penn Medicine Medical Device Accelerator for supporting equipment for this research.

Setting
Academic hospital. University of Pennsylvania, Philadelphia, PA.





Figure. A. Operator wearing AR headset and viewing preprocedural imaging immediately prior to the procedure. B. Captured image clip from Video 2 showing holographic 3D MRI volume in the interventional suite.

Summary

AR has seen tremendous development and promising prospects in recent years. AR headsets in particular have allowed visualization of holographic models and cross-sectional scans in true 3D space rather than flattened to 2D screens. The added depth information as well as 3D manipulation of the cross-sectional imaging may improve learning, surgical planning, and procedural efficiency. Nevertheless, these potentially beneficial impacts remain largely unstudied.

The authors designed a preclinical prospective trial using a rat model to determine if preprocedural AR visualization of MRI may improve procedural metrics. With institutional animal care approval, the authors utilized a previously established dithylnitrosamine (DEN) induced HCC rat model. 28 rats with HCCs larger than 5 mm on pre-procedural MRI scan were prospectively enrolled, 12 in the AR visualization prior to transarterial embolization arm and 16 in the control arm. Preprocedural images were always reviewed prior to intervention, in 2D plane for the control arm and in 2D+3D AR fashion for the AR visualization arm. Embolization was performed through a cut-down femoral access with 0.05 mL of 40-120 um Embosphere or 40-90 um LC Bead LUMI particles diluted in 0.9 mL of Omnipaque 300 until stasis in the selected segmental haptic artery. Total femoral artery catheterization time, total fluoroscopy time, dose-area product (DAP), and air kerma (AK) were recorded and compared. Given post-hoc power analysis showing a sample size of 52 was needed for 80% power with an effect size of 0.8 and alpha of 0.05, 15 additional cases were identified retrospectively and added to the control arm.

Analyses using only prospective data demonstrated total catheterization time reduction from 42.7 to 31.0 minutes, p=0.11, in the AR visualization arm compared to the control arm. Total fluoroscopy time decreased from 11.7 to 7.4 minutes, p=0.12, compared to the control arm. DAP and AK did not change significantly between the two arms. AR setup and viewing added 5.9 minutes of pre-procedural preparation time per case on average. 15 additional retrospective cases were identified and determined to be statistically similar to the prospective control arm. Using both combined retrospective and prospective controls, the decrease in total fluoroscopy time was statistically significant with p=0.01. Furthermore, there were statistically significant reductions in the variability of catheterization and fluoroscopy times in the AR visualization arm.

Commentary

The authors in this paper have evaluated the potential impact of 3D AR visualization in pre-procedural planning for locoregional liver therapies in a preclinical rat animal model. Prospective comparisons did not reach statistical significance. Factors including the use of human-calibrated angiographic systems on rats, different embolic agents, and small sample size may have compounded the comparisons. Addition of appropriate retrospective cases demonstrated a significant decrease in total fluoroscopy time. This reduction in total fluoroscopic times, variations in particular, suggested benefits of 3D AR visualization in diminishing excessive or unplanned fluoroscopy use. These results were compatible with prior studies showing decreased mental task load in AR simulated surgery as well as decreased needle passes and DAP on AR abdominal phantom simulations of CT-guided interventions. Preliminary data, such as the results reported in this paper, together with foreseeable benefits of 3D AR visualization for pre-procedural planning and intra-procedural guidance should prompt future animal studies, potentially with large animal models, and eventual human prospective trials. We may be on the verge of another technological breakthrough in procedural visualization after the adaptation of fluoroscopy and laparoscopy.

Post Author
Ningcheng (Peter) Li, MD, MS
Integrated Interventional Radiology Resident, PGY-4
Department of Interventional Radiology
Oregon Health and Science University, Dotter Interventional Institute 

@NingchengLi

Embolization for Pelvic Venous Disorders in Women

Pelvic Venous Disorders in Women due to Pelvic Varices: Treatment by Embolization: Experience in 520 Patients

Clinical question
Is pelvic vein embolization with metallic devices a safe and effective treatment for pelvic venous disorders in women with chronic pelvic pain?

Take away point
Over 5 years of follow up, pelvic vein embolization with metallic devices significantly decreased symptomatology with a 5% recurrence rate and 2.1% major complication rate.

Reference
De Gregorio MA, Guirola JA, Alvarez-Arranz E, Sánchez-Ballestin M, Urbano J, Sierre S. Pelvic Venous Disorders in Women due to Pelvic Varices: Treatment by Embolization: Experience in 520 Patients. J Vasc Interv Radiol. 2020;31(10):1560-1569. doi:10.1016/j.jvir.2020.06.017

Click here for abstract

Study design
Single-institution cohort study of 520 women undergoing pelvic vein embolization with either metallic coils or vascular plugs for symptomatic pelvic venous disorders.

Funding source
No reported funding.

Setting
Academic hospital, University of Zaragoza, Spain.




Figure
The evolution of pelvic pain by visual analog scale in women with pelvic venous disorder treated by an embolization procedure using metallic devices (coils or plugs). FPC = fibered platinum coil; VP = vascular plug.

Summary

Embolization of the pelvic veins is the treatment of choice for pelvic venous disorders (PeVDs); however, evidence regarding safety and efficacy of this treatment is limited. The authors performed an observational study of 520 cases of PeVD treated with metallic device embolization with interval follow up over a 5-year period.

Women presenting with clinical symptoms of PeVD for more than 6 months without evidence of other causative pathology, with a transvaginal ultrasound diagnosis of pelvic varicosities, and with venography showing grade II or III reflux as defined by the Hiromura classification, retention of contrast in the pelvic venous plexus, and/or filling of the vulvovaginal or lower extremity varicose veins were included in the study. Patients with malignancy or vascular compression syndromes were excluded as were patients who received other embolic devices or agents.

Embolization was achieved with either fibered platinum coils or vascular plugs with the primary procedural endpoint being occlusion of the four main pelvic veins (MPVs): the left and right ovarian veins and the left and right internal iliac veins. All devices were oversized by approximately 20-35% in ovarian veins and 15-20% in internal iliac veins.

Follow up exams were conducted at 1, 3, 6, and 12 months and then annually up to 5 years at which times clinical symptoms were evaluated using a 0-10 point visual analog scale (VAS) and transvaginal ultrasound. Recurrence and complication data were also tracked over the follow up period.

A total of 520 women met criteria with 261 undergoing embolization with coils and 259 with vascular plugs. Technical endpoint success was 84.8% with 100% success of embolization of at least one MPV. There was a 5% recurrence rate with 65.3% of those cases undergoing reintervention. There were 57 minor complications (10.9%) including access site hematoma, ovarian vein extravasation, and low back pain. There were 11 major complications, all of which were device migration (2.1%). Ten of the major complications were seen in patients receiving coil embolization and one in a patient who received plug embolization. No patient deaths were reported.

Average length of follow up was 58.7 ± 5.7 months with significant decrease in reported pain level of 7.63 ± 0.9 pretreatment to 0.91 ± 1.5 at 5 years posttreatment. Time to clinical improvement was 14.2 ± 0.9 months for patients with severe pain (VAS score of 8-10) and 8.6 ± 1.3 months in patients with moderate pain (VAS score of 5-7). There were no statistically significant differences between groups treated with coils or plugs.

Commentary

The authors investigate the safety and efficacy of metallic device embolization of the pelvic veins in a relatively large cohort of women with symptomatic PeVD. Although the authors designate their study as retrospective, the nature of their data collection is prospective (patients were consented for study participation prior to intervention and symptomatology metrics were assessed at baseline and future follow up). While this prospective nature adds to the reliability of the results, if the study had been run as a randomized controlled trial (RCT) between coils and plugs, it would have offered an even more robust comparison, particularly since previously published RCTs comparing coils and plugs have not had as large a sample size nor as long term a follow up. Furthermore, although major complication rate between groups was not statistically significant, there was arguably clinical significance in device migration rate with 10/11 instances of device migration occurring in cases of coil embolization. Comparison via RCT would offer further insight into these results. Overall, the strength of this study lies in its large sample size and long term follow up data. The significant and persistent decrease in symptomatology with low complication rates adds to existing data supporting pelvic vein embolization as treatment for symptomatic PeVD. The authors discuss that additional studies comparing specific agents and devices is needed to fully understand treatment options for PeVD.

Post Author
Catherine (Rin) Panick, MD
Resident Physician, Integrated Interventional Radiology
Dotter Interventional Institute
Oregon Health & Science University

@MdPanick

Post-Procedure Residual Thrombus and Clinical Outcome in DVT Receiving Pharmacomechanical Thrombolysis

Correlation Between Post-Procedure Residual Thrombus and Clinical Outcome in Deep Vein Thrombosis Patients Receiving Pharmacomechanical Thrombolysis in a Multicenter Randomized Trial

Clinical question
Does residual thrombus on post-procedure venogram correlate with clinical outcomes following phamracomechanical thrombolysis for DVT?

Take-away point
No correlation is noted between volume of residual thrombus and severity of post-thrombotic syndrome.

Reference
Mahmood K Razavi et al. Correlation between Post-Procedure Residual Thrombus and Clinical Outcome in Deep Vein Thrombosis Patients Receiving Pharmacomechanical Thrombolysis in a Multicenter Randomized Trial. Journal of Vascular and Interventional Radiology. 2020: 31; 1517-1528.

Click here for abstract

Study design

Randomized Trial

Funding source

Self-funded or unfunded

Setting

Multi-Center

Summary

This study utilized the ATTRACT trial database to assess the relationship between post-procedure venograms following pharmacomechanical catheter-directed thrombolysis (PCDT) for proximal DVT and outcomes, specifically post thrombotic syndrome. Briefly, 317 patients with ioliofemoral or femoral-popliteal DVT were included. Venograms were assessed for post-procedure thrombus burden and post-thrombotic syndrome and quality of life was measured at 1, 12, and 24 months.

PCDT was noted to significantly reduce thrombus volume in all vein segments. Complete thrombolysis was documented in 30% of the patients. Post-PCDT thrombus burden (as measured by Marder score) did not correlate with 24-month Villalta score, Venous Clinical Severeity Scale, nor venous disease-specific qualtiy of life survey. Within the PCDT arm of the ATTRACT trial, "patients who developed PTS did not have more end-of-procedure residual thrombus than those who did not develop PTS", with PTS seen in 46% of patients with complete thrombolysis and 47% and 53% of patients with minor residual and substantial residual thrombus respectively. Notably, complete thrombolysis was correlated with reduced PTS severity within the iolofemoral DVT cohort.

Commentary

Traditionally, the goal of catheter directed thrombolysis revolved around leaving an open vein-with prompt removal of thrombus burden leading to preserved valvular function and reduced PTS symptoms. Within the ATTRACT trial, PCDT successfully removed thrombus volume and while it had no significant impact on PTS occurence, it was correlated with reduced sypmtoms and better quality of life. This current study further clarifies this study, examining the PCDT outcomes based on venographic results. This data further illuminates our lack of understanding of the pathophysiology behind PTS.

Post Author:

David M Mauro, MD
Assistant Professor
Department of Radiology, Vascular and Interventional Radiology
University of North Carolina

@DavidMauroMD

Antibiotic after Uterine Artery Embolization

Evaluation of the Effect of Routine Antibiotic Administration after Uterine Artery Embolization on Infection Rates

Clinical question
What is the effectiveness of routine administration of post-procedure antibiotics after uterine artery embolization (UAE) to prevent procedure-related infections?

Take-away point
No increased rate of infections were seen after UAE for fibroids when post-procedure antibiotics were discontinued.

Reference
Evaluation of the Effect of Routine Antibiotic Administration after Uterine Artery Embolization on Infection Rates. Graif, A. et al. Journal of Vascular and Interventional Radiology, Volume 31, Issue 8, 1263-1269.

Click here for abstract

Study design
Single-center retrospective cohort study

Funding source
No funding

Setting
Private hospital: Christiana Care Health System, Newark, DE




Visual synopsis

Summary

Given the increasing need for antibiotic stewardship and further development of UAE treatment, a single-center retrospective cohort study was performed to address the infection rate following UAE for fibroids when no post-procedure antibiotics were given. In 2018 the SIR last recommended the use of pre-procedure antibiotics for UAE. However, post-procedure antibiotics are not recommended unless there is evidence of possible infection. Despite these recommendations, many patients still receive a post-procedure course of antibiotics. Previous UAE studies acknowledge post-procedure antibiotic use, however no subgroup analyses regarding specific antibiotic usage were performed. In the HOPEFUL study (Hysterectomy Or Percutaneous Embolisation For Uterine Leiomyoma), it showed benefit from expected general side effects after the procedure, but no overall effect in the rate of infections. Therefore, this study aims to address the effectiveness of routine administration of post-procedure antibiotics after UAE in the prevention of procedure-related infection.

At this private institution prior to 2016, patients who received routine pre and post procedure antibiotics (n=217) were compared to those after 2016, where no post-procedure antibiotics (n=158) were given. Pre-procedure antibiotics for the no-antibiotics group consisted of weight based dose of IV cefazolin, whereas the post-procedure antibiotics group received IV 500mg ciprofloxacin. Post-procedure antibiotics were oral ciprofloxacin 500mg twice daily for five days. These two groups were compared for infectious complications with primary endpoints being an infectious complication requiring therapy with antibiotics, re-admission or surgical intervention within three months. Infections were subsequently classified as minor or major. The secondary endpoint was 90-day mortality. Demographics were similar between the two groups, though the no-antibiotics group had a significantly higher rate of diabetes and a lower rate of adenomyosis. The procedure was similar in each group with regards to arteries embolized, number of vials used and procedural steps. However, in the antibiotics group patients received only embospheres, whereas in the no post-procedure antibiotics group patients received embospheres, embozene or both.

No statistically significant difference was seen between the number of infections (P=.66) when comparing the post-procedure antibiotics group (4/217, 1.8%) to the no-antibiotics group (2/158, 1.3%). Overall infection rate was (6/375, 1.6%), occurring at a median of 15.5 days. Overall minor complications (3/375, 0.8%) did not differ between the groups. The primary symptom was malodorous vaginal discharge, requiring empiric oral antibiotic therapy. Overall major complication rates also did not differ between the groups (3/375, 0.8%). Major infectious complications resulted in two patients who underwent hysterectomy and one patient receiving a myomectomy. No 90-day mortalities were seen. Regardless of antibiotic usage, infectious rates and complications found in this study mirror previous large retrospective studies and meta-analyses. The authors conclude that post-procedure antibiotic prophylaxis after UAE did not result in increased rates of minor or major infectious complications.

Commentary

This study helps underscore the current SIR antibiotic recommendations and encourages practitioners to use post-procedure antibiotic prophylaxis cautiously. Previous studies lacked the clarity behind specific antibiotic usage and regimens that this study addresses. However, there are a few aspects to this paper regarding power, type of study, and the differences between the two groups that should be considered.

This study lacks power given its smaller sample size and generalizability due to its single-center retrospective nature. Due to the lack of power, they were not able to perform regression analyses based on types of particles used and characterization of fibroid disease, both of which may play a role in procedure related infections. Reassuringly, this study has similar infectious rates when compared to previous large prospective studies. Differences between the two groups that should be considered are differing pre-procedure antibiotic regimen, variation of embolization particles and their loss to follow up rate. Though complications were low and similar to previous studies, overall 50% of complications were minor and 50% were major. The main minor complication noted was malodorous discharge. This may also be underreported or not fully captured given the 13.4% of those lost to follow up. Overall, this is an important study that guides the decision on whether or not to prescribe post-procedure antibiotic prophylaxis in UAE.

Post Author
Marissa Stumbras, MD
Interventional Radiology Resident, PGY2
Oregon Health & Science University

@MarissaStumbras

External Beam Radiation Versus Percutaneous Image-guided Cryoablation for Palliation of Uncomplicated Bone Metastases

Cost Effectiveness of External Beam Radiation Therapy Versus Percutaneous Image-guided Cryoablation for Palliation of Uncomplicated Bone Metastases

Clinical question
Is percutaneous image-guided cryoablation a cost effective method for pain palliation in uncomplicated bone metastatic lesions? How does it compare to external beam radiation and in what combination?

Take-away point
Cryoablation is not cost effective for palliation of uncomplicated bone metastases in the initial setting. However, cryoablation is a potentially cost effective alternative for recurrent pain palliation following external beam radiation therapy.

Reference
Cost effectiveness of external beam radiation therapy versus percutaneous image-guided cryoablation for palliation of uncomplicated bone metastases. Chang, E.M., Shaverdian, N., Capiro, N., Steinberg, M.L., Raldow, A.C. Journal of Vascular and Interventional Radiology (JVIR), Volume 31, Issue 8, 1221-1232.

Study design
Cost effectiveness analysis using a Markov model with 1-month cycles over a lifetime horizon, 2017 Medicare outpatient setting reimbursement as cost estimate, and $100,000 per quality-adjusted life-year as willingness-to-pay threshold. Strategies evaluated included external beam radiation therapy (RT) in single fraction (SF) followed by SFRT, SFRT-ablation, ablation-SFRT, multiple-fraction radiation therapy (MFRT) followed by MFRT, MRFT-ablation, and ablation-MFRT.

Funding source
No funding source was disclosed.

Setting
Academic hospital. University of California Los Angeles, Los Angeles, California.







Figure. Visual synopsis.

Summary

Metastatic lesions to the bone, which is the third most common site of metastatic disease after lung and liver, carry significant morbidities, as 50% of patients would develop poorly controlled pain. Radiation therapy (RT) is a well-established treatment however onset of pain relief may take up to 6 weeks. Percutaneous image-guided cryoablation may be a good alternative given its rapid onset of pain relief but it carries an associated procedural cost. Therefore, a cost-effectiveness analysis is needed to assess the optimal utilization of cryoablation in combination with radiation therapy, whether it be single fraction (SFRT) or multiple fraction radiation therapy (MFRT).

The authors performed a cost effectiveness analysis using a Markov model with 1-month cycles over a lifetime horizon, 9 months as median overall survival, outcome probabilities extracted from medical literature, 2017 Medicare outpatient setting reimbursement and 2016 Agency for Healthcare Research and Quality data as cost estimate, $100,000 per quality-adjusted life-year as willingness-to-pay threshold, and 1 million simulated patients. Strategies evaluated included external beam radiation therapy (RT) in single fraction (SF) followed by SFRT, SFRT-ablation, ablation-SFRT, multiple-fraction radiation therapy (MFRT) followed by MFRT, MRFT-ablation, and ablation-MFRT. SFRT was defined as 8 Gy in 1 fraction. MFRT was defined as 30 Gy in 10 fractions. Ablation-ablation was not included as a treatment strategy given very limited evidence of outcomes following repeated cryoablations.

Using RT-RT as a baseline (SFRT and MFRT for their respective comparisons), RT-ablation was found to be cost effective but not ablation-RT. Tornado analysis, specifically for comparison between SFRT-SFRT and SFRT-ablation demonstrated that the results were most sensitive to probability of return of pain and probability of pain relief after cryoablation. Other important variable dependency included median overall survival. RT-RT remain the most cost-effective for median survival <= 8.7 months for SFRT and <= 7.9 months for MFRT. Ablation-RT became more cost-effective for median survival >= 196.4 months for SFRT and >= 19.8 months for MFRT. RT-ablation was the most cost-effective for median survival in between the above mentioned intervals.

Commentary

The authors in this paper have evaluated in details the cost-effectiveness of percutaneous image-guided cryoablation in the setting of uncomplicated bone metastatic lesions for pain palliation in combination with radiation therapy. With a current median overall survival of 9 months, radiation therapy followed by ablation is the most cost-effective. This information is important for referring clinicians and patient advocates. As the authors have also noted, the analyses were highly sensitive to effectiveness of cryoablation as well as median overall survival. A stratified clinical pathway may be proposed with patients with poor prognosis undergoing radiation therapy followed by radiation therapy while patients with longer expected survival may benefit from ablation followed by radiation therapy with regards to cost-effectiveness. More data from prospective trials, particularly on the pain relief/recurrence rate after cryoablation, as well as ongoing economic and clinical assessment will be needed to further delineate the optimal treatment pathway and modality choice. Clinical decisions in other treatment pathways may benefit from rigorous cost-effectiveness analyses such as this paper presented by the authors.

Post Author
Ningcheng (Peter) Li, MD, MS
Integrated Interventional Radiology Resident, PGY-4
Department of Interventional Radiology
Oregon Health and Science University, Dotter Interventional Institute 

@NingchengLi

Fibrinogen Levels during Catheter-Directed Thrombolysis for Acute PE

Evaluation of Fibrinogen Levels during Catheter-Directed Thrombolysis for Acute Pulmonary Embolism

Clinical question
How are plasma fibrinogen level (PFL) affected by catheter-directed thrombolysis (CDT) in the setting of acute pulmonary embolism (PE) and is PFL associated with hemorrhagic complications in this setting?

Take-away point
CDT significantly decreases PFL, but is not associated with hemorrhagic complications.

Reference
Graif A, Grilli CJ, Kimbiris G, Paik HH, Leung DA. Evaluation of Fibrinogen Levels during Catheter-Directed Thrombolysis for Acute Pulmonary Embolism. J Vasc Interv Radiol. 2020;31(8):1281-1289. doi:10.1016/j.jvir.2020.04.032

Click here for abstract

Study design
Retrospective, single-institution cohort study of 147 patients undergoing CDT for acute massive and submassive PE.

Funding source
No reported funding 

Setting
Private hospital network, Christiana Care Health System, USA.






Figure. Visual synopsis summarizing of study design and main results.

Summary

Catheter-directed thrombolysis (CDT) with tissue plasminogen activator (tPA) for acuate pulmonary embolism (PE) is thought to mitigate, although not eliminate, hemorrhagic risk compared to systemic thrombolysis. Some clinicians monitor plasma fibrinogen level (PFL) to anticipate hemorrhage, but supportive evidence is lacking. The authors performed a retrospective study of 147 cases of CDT for acute PE and evaluated PFL and its relationship with hemorrhagic complications.

Patients included in the study were adults presenting with acute massive or submassive PE who received either conventional catheter-directed thrombolysis (CCDT) or ultrasound-accelerated thrombolysis (USAT). Patients were excluded if presenting symptoms were >14 days, chronic PE was evident on CTA, or systemic tPA had been given prior to CDT. All patients received systemic anticoagulation with either unfractionated heparin (UFH) or low molecular weight heparin (LMWH).

Primary endpoints included change in initial and final PFL (with subgroup analyses of CCDT vs USAT and UFH vs LMWH groups) and PFL nadir. Secondary endpoints included correlation between PE severity metrics with PFL as well as tPA infusion rate, duration, and total dose.

A total of 147 cases met criteria with 98 undergoing CCDT, 34 undergoing USAT, and 15 undergoing a combination of both (excluded from CCDT vs USAT subgroup analysis). Anticoagulation was achieved with UFH in 102 cases and LMWH in 45 cases. Primary results showed a significant mean decrease from initial PFL to final PFL (-15.1 ± 69.4 mg/dl, p=0.007) and a PFL nadir of 327.6 ± 107.1 mg/dl.

Subgroup analyses did not reveal a significant difference in initial or final PFL between patients receiving UFH or LMWH; although, PFL nadir was significantly lower in the UFH group (313.7 ± 97.4 mg/dl, p= 0.03). No significant difference in initial, final or nadir PFL levels was detected between CCDT and USAT groups. In the CCDT group, there was a significant decrease in initial and final PFL (-14.9 ± 60.9 mg/dl, p=0.01) compared to the USAT group, which showed a nonsignificant increase in initial and final PFL. Secondary endpoint results showed no significant correlation between PE severity indices and any PFL or infusion metrics.

Six hemorrhagic complications were observed with no significant difference in change in PFL or between final PFL, PFL nadir, or change in PFL compared to cases without hemorrhagic complication.

The authors discuss that although there was a significant decrease in PFL during CDT for acute PE, this did not translate to clinical significance as PFL did not reach commonly used thresholds for modification or discontinuation of CDT. Two other, smaller studies evaluating PFL during CDT found similar decreases in PFL, although did not evaluate hemorrhagic complications. One study found a moderate positive correlation between PFL nadir and PE severity, which conflicts with the nonsignificant results from the current study.

Commentary

The authors evaluate PFL in a relatively large cohort of patients undergoing CDT. The larger sample size compared to previously published studies offers increased confidence in the main conclusion that PFL is significantly decreased in this population. However, they discuss that their study was insufficiently powered to evaluate the relationship between PFL and hemorrhagic complications given the very small number of total hemorrhagic complications (n=6). Additionally, the retrospective nature of this study inherently introduces inconsistencies and confounds, which can be amplified in the smaller subgroup analyses. Despite a significant primary endpoint, more data are needed to fully explore the relationship between PFL and hemorrhagic complications in this subgroup of patients receiving CDT for acute PE before any changes to clinical management can be made confidently.

Post Author
Catherine (Rin) Panick, MD
Resident Physician, Integrated Interventional Radiology
Dotter Interventional Institute
Oregon Health & Science University

@MdPanick

Predictors of PFS and Local Tumor Control after Percutaneous Thermal Ablation of Oligometastatic Breast Cancer

Predictors of Progression-Free Survival and Local Tumor Control after Percutaneous Thermal Ablation of Oligometastatic Breast Cancer: A Retrospective Study

Clinical question
What predicts local progression and progression-free survival following ablation of oligometastatic disease in breast cancer?

Take-away point
Thermal ablation can locally eliminate tumor progression for pulmonary, hepatic, bone and soft tissue oligometastatic disease in breast cancer if margins are greater than 5 mm.

Reference
Ridouani F et al. Predictors of Progression-Free Survival and Local Tumor Control after Percutaneous Thermal Ablation of Oligometastatic Breast Cancer: A Retrospective Study. Journal of Vascular and Interventional Radiology. July, 2020.

Study design

Retrospective Review

Funding source

Self-funded or unfunded

Setting

Single Institution






Figure 2. (Left column) Kalpan-Meier analysis demonstrates PFS from the time of initial ablation for all patients (top), for eradication of disease vs control of disease groups (P = .05) (second row), ER-positive compared to ER-negative patients (P= .037) (third row), and by minimal ablation margin of 5 mm (P= .33). (Right column) Kaplan-Meier analysis shows TTP from initial ablation for all patients (top row), for eradication of disease vs control of disease groups (P =.29), ER-positive compared to ER-negative patients (P= .08) (third row), and by minimal ablation margin of 5 mm (P= .036) (bottom row). The x-axes are months, and the y-axes are proportion at risk. ER-receptor status and age ≤ 60 years old demonstrated significant improved PFS. Additionally, ablation margin ≥ 5 mm showed longer median TTP (13 versus 5 months). Adverse events were noted to be moderate in 8% of liver ablations and 28% in lung ablations. 

Summary

Utilizing a single-center, retrospective database search, the authors identified 33 patients (46 ablations) with 5 or fewer enlarging or increasingly metabolically active breast cancer metastatic lesions who underwent thermal ablation to the lung, liver, bone, or soft tissues. Radiofrequency ablation, microwave ablation, or cryoablation was performed with computed tomography, positron-emission tomography, or magnetic resonance image guidance. 35 liver (76%), 7 lung (15%), and 4 soft tissue or bone (8%) metastases were treated. 78% of patients were estrogen receptor positive, 51% progesterone receptor positive, 27% human epidermal growth factor receptor (HER2) positive, and 9% were triple negative. The median time from metastatic diagnosis wot ablation was 39 months. All patients received systemic chemotherapy, hormone therapy, or targeted therapy. Additionally, some patients also had surgical, radiation, or trans-arterial treatment.

91% of the procedures had technical success defined as no residual disease on initial post-procedure imaging. Local tumor progression was noted in 5 patients (15%) at 4-9 months following ablation. Ablation margins were measured in 83% of ablations with median margin being 6 mm. Median overall survival from first ablation treatment was 70 months with 1, 3, and 5 year survivals of 96%, 72%, and 55%. Median progression free survival was 10 months with median time to progression of 11 months.

Commentary

With breast cancer being so common and greater than a quarter of these patients developing metastatic disease, this creates a large population of patients necessitating treatment. Studies have suggested that local treatment of breast cancer metastases may improve survival. This study added to this growing body of literature. Unsurprisingly, results were best in younger patients and larger margins. However, greater performance free survival was also seen in ER-positive patients.

Percutaneous ablation is clearly feasible and in appropriately selected patients have comparable results to surgery. Additionally, eradication of all disease can allow patients to take holidays from their systemic therapies.

Limitations include a small sample size, especially when considering four sites of disease and three ablation modalities. Additionally, image guidance used in this study, including PET/CT and MR guidance, is not widely available. However, clearly ablation should be included in the treatment paradigm who would benefit from treatment of their oligometastatic disease and tumor boards should consider this therapy in addition to surgery, radiation, and trans-arterial treatments.

Post Author:
David M Mauro, MD
Assistant Professor
Department of Radiology
Vascular and Interventional Radiology
University of North Carolina

@DavidMauroMD

Intermediate to Long-Term Clinical Outcomes of Percutaneous Renal Masses Cryoablation

Intermediate to Long-Term Clinical Outcomes of Percutaneous Cryoablation for Renal Masses

Clinical question
What is the intermediate- and long-term efficacy and safety of percutaneous cryoablation (CA) in the treatment of renal masses?

Take-away point
CA is effective in treating renal masses with low rates of complications during the procedure and over intermediate- and long-term follow-up periods.

Reference
Knox J, Kohlbrenner R, Kolli K, et al. Intermediate to Long-Term Clinical Outcomes of Percutaneous Cryoablation for Renal Masses. J Vasc Interv Radiol. 2020;31(8):1242-1248.

Click here for abstract

Study design
Retrospective cohort study

Funding source
Self-funded or unfunded

Setting
Single institution, University of California San Francisco








Figure. Graph of overall survival (OS) Kaplan-Meier curve in patients with RCC

Summary

Procedural treatment of renal masses has classically been accomplished using partial or total nephrectomy. While newer percutaneous cryoablation (CA) and thermal ablation techniques have been shown to be safe and effective compared to surgery for T1 disease, there is a paucity of data on their intermediate- and long-term safety and efficacy.

In this study, the investigators sought to assess the intermediate- and long-term safety and efficacy of percutaneous CA for renal masses at a single institution. Patients who had undergone ablation with percutaneous CA for T1a or b renal masses were selected. Patients with multiple masses, history of prior nephrectomy, and inherited tumor syndromes were included. Outcomes included renal function pre- and post-procedure, intra- and post-procedure complications, local recurrence, new metastatic disease, or complete response. R.E.N.A.L. nephrectomy score, a metric evaluating renal mass complexity that was previously validated as a measure of 30-day nephrectomy morbidity, was also calculated for each renal cell carcinoma (RCC) mass.

277 patients, 297 renal masses, and 299 CA procedures were analyzed. 207 masses were <3 cm, 74 were between 3 and 4 cm, and 16 were greater than 4 cm. 22 patients underwent multiple ablations; 12 due to separate mass, 7 due to incomplete initial ablation, and 3 due to recurrence. 46 patients had a history of prior renal surgery before CA. 4 patients had a known underlying genetic disease associated with their renal masses. 234 masses were confirmed RCC, 40 had nondiagnostic biopsies, and 8 had no biopsy results. 15 were biopsied at time of CA but were later found to be benign. Of the 234 RCC tumors, there were 93 (39.7%), 114 (50.8%), and 27 (11.5%) low-, intermediate-, and high-nephrectomy scoring masses respectively. There was no significant difference between pre-and 1-day post-procedural eGFR, but eGFR declined an average of 2.4 mL/min/1.73 m2 from preprocedural values to 3-month follow-up. There was no difference in decline between patients with and without prior renal surgeries or between patients with or without history of contralateral nephrectomy.

12 major complications occurred in 9 procedures (3%) with none resulting in death or permanent disability. AKI requiring hospitalization occurred 5 times, with none of the patients requiring hemodialysis. One patient suffered a retroperitoneal hematoma requiring transfusion and one patient had a renal artery pseudoaneurysm treated with embolization. Additionally, single occurrences of hemothorax, NSTEMI, post-procedural pulmonary embolism, high fever, and traumatic bladder catheter placement were all noted. Major complications occurred at a higher mean age (73.1) compared to uncomplicated procedures (65.6) (p=0.03). Tumor characteristics and high nephrectomy score did not affect complication rate (p=0.97) but significantly more complications occurred in patients with history of prior renal surgery (p<0.05).

For the 199 patients with RCC masses and follow-up information, mean clinical and imaging follow-up length was 29.7 months and 27.4 months respectively. Complete response was achieved in 195 masses (95.6%) after one procedure and 200 (98%) after 2 procedures. Mean time to complete response was 4.2 months. Local recurrence was noted in 3 cases (1.5%). Mean time to recurrence was 42.9 months (19.9-76.9 mo.). There was no association between recurrence and specific RCC mass characteristics. Recurrence did occur more often in patients with history of prior renal surgery (p=0.03). 10 patients developed metastatic disease (5.2%) at a mean follow-up time of 38.3 months. Independent factors associated with metastatic progression or local recurrence included history of prior kidney surgery, increased mass size, and clear cell subtype.

Commentary

In this cohort, CA was demonstrated to be a safe and effective treatment modality for patients with renal masses. It offered high response rates with low recurrence and metastatic progression, and had lower complication rates than previous partial nephrectomy studies. Noted decreases in eGFR at 3-month follow-up were unlikely clinically significant and were less than those reported for partial nephrectomy. Patients with prior kidney surgery were at higher risk of complications, local recurrence, or metastatic disease, consistent with prior studies. Additionally, patients who experienced metastatic progression had aggressive disease features, bilateral disease, or did not have complete response after their first ablation. This study is limited by its retrospective nature and single arm design. Future studies will prospectively compare partial nephrectomy and CA procedures over extended follow-up periods.


Post Author
Jared Edwards, MD
General Surgery Intern (PGY-1)
Department of General Surgery
Naval Medical Center San Diego, San Diego, CA

@JaredRayEdwards

Venous Biomechanics Poisson Effect

Venous Biomechanics of Angioplasty and Stent Placement: Implications of the Poisson Effect

Clinical question
Characterize the poisson effect following venous angioplasty and stents placement in veins.

Take-away point
There is a proportional longitudinal foreshortening and narrowing of adjacent venous segments with radial expansion of venous angioplasty and stents, which is more dramatic in veins than arteries.

Reference
Li N., Mendoza F., Rugonyi S., Farsad K., Kaufman J.A., Jahangiri Y., et al. Venous Biomechanics of Angioplasty and Stent Placement: Implications of the Poisson Effect. J Vasc Interv Radiol. 2020 Aug; 31 (8): 1348-1356.

Click here for abstract

Study design
Prospective in Vivo swine model Testing with Real-Time Venous Wall Motion Monitoring and finite-element computational vascular model analysis

Funding source
No reported funding

Setting
Academic setting. Oregon Health and Science University, Portland, Oregon, USA







Figure
A visual synopsis of the 2 study parts and summary of results.

Summary

Venous angioplasty and stent placement for treating venous outflow obstruction has demonstrated improved flow with clinical symptom relief. However, adjacent segment narrowing after stent placement, based on the poisson effect, may carry a negative impact on the quality of venous flow. Research on venous biomechanics for venous-specific stent designs is lacking. The author performed a prospective 3 adult swine in vivo testing with real-time venous wall motion monitoring and finite-element computational vascular model analysis to characterize the poisson effect during angioplasty and stent placement. Statistical analysis including Welch t test, analysis of variance, Pearson correlation, linear regression, and polynomial curve fit were performed using Prism software.

1- Real-Time Venous Wall Motion Monitoring:

Study veins were accessed and baseline venography was obtained followed by RF ablation induced stenosis and repeat venography. Balloon angioplasty, with diameter matching the naive vein(8mm), was performed on the in the stenotic regions of one side. Bare metal stents oversized by 50% (12mm) were deployed in the contralateral stenotic region. Iron particles were injected on the venous endothelium proximal to the intended vessel segment and categorized into near group (mid-point to balloon) and far group (peripheral to angioplasty area). Neodymium magnet was placed externally for iron attraction allowing real-time visualization of the vessel wall under fluoroscopy.

· During balloon angioplasty, the mean venous stenosis decreased by 43.7% ± 2.1. There was significant longitudinal displacement of the iron particles toward the balloon midpoint(1.5% ± 0.2 of the balloon length P <.001) affecting the far group more (2.2%) compared to near group (0.9%)(t test, P< .001). The adjacent luminal collapse correlated with diameter increase of the angioplasty-treated segment (relative collapse % . 0.772 * [relative dilatation %] . 0.255; R2 . 0.8920.

· During bare metal stent deployment the mean venous stenosis reduced to 20.8% ± 0.8, with further reduction to 1.6% ± 1.2 with balloon angioplasty of the stent. There was significant longitudinal displacement toward the midpoint of the balloon(2.0% ± 0.5 of the balloon length P< .01). The longitudinal displacement increased with distance to the midpoint of the balloon in a direct linear relationship (R2 . 0.87).

2- Finite-Element Computational Vascular Model (using ADINA software)

Several parameters were obtained from the literature to simulate a healthy common iliac vein and artery. During angioplasty simulation, the reduction of the adjacent-segment diameter had a significant correlation to the degree of dilation of the treated segment. Angioplasty simulation using arterial wall biomechanical properties showed significantly less adjacent segment narrowing compared with the model using venous properties. Variations of Young moduli in the longitudinal direction had a positive relationship with the amount of adjacent segment collapse, while with circumferential direction had the opposite effect and with the radial direction had no significant impact.

The findings explain the decrease of external iliac vein diameter after stent placement in the common iliac vein. Such phenomenon is due to the nonlinear elastic property of veins secondary to the nonaligned collagen fibers in the predominant adventitia. In contrast, arteries have coaligned collagen fibers in the dominant media layer. Previous and current study showed that veins are more extensible in the circumferential direction than in the longitudinal direction since they have a much higher longitudinal young modulus and a higher longitudinal vs circumferential Poisson ratio (opposite to arteries). With radial outward force applied to venous segments, there is a significant redistribution of forces and venous tissue, resulting in a pronounced Poisson effect.

Commentary

The authors in this study captured an important consequence of venous angioplasty and stent placement. They characterized its dramatic Poisson effect in veins and showed the resulting longitudinal foreshortening and adjacent segment collapse. Although the study has limitations including the small sample size, the possible collagen contraction after RF ablation and the lack of survival period to examine chronic changes. The study can still provide innovative solutions on vein-specific flow optimization. Current stent designs place heavy emphases on maximizing radial resistive force and chronic outward force, which may be counterproductive in venous interventions. Therefore applying and examining this study phenomenon on novel innovative venous stents, with emphasis on overcoming force and tissue redistribution related to the Poisson effect, might maximize venous flow leading to better patient outcomes.

Post Author
Tarig Elhakim, MD
PGY-2 Internal Medicine Residency,
Kendall Regional Medical Center

@TarigElhakim

Ablation Therapy for Advanced Stage NSCLC

Ablation Therapy for Advanced Stage Non-Small Cell Lung Cancer: A National Cancer Database Study

Clinical question: 

In patients with clinical stage IIIB or stage IV non-small cell lung cancer (NSCLC), is overall survival (OS) prolonged in patients who undergo ablation therapy (AT) compared to patients who do not receive AT?

Take away point: 

In patients with advanced stage NSCLC, AT as the sole therapy other than chemotherapy may be associated with prolonged overall survival.

Reference: 

Halsey, Kasey et al. (2020). “Ablation Therapy for Advanced Stage Non-Small Cell Lung Cancer: A National Cancer Database Study.” Journal of Vascular and Interventional Radiology 31 (8): 1210-1215.

Click here for abstract

Study design: 

Retrospective review

Funding source: 

National Natural Science Foundation of China grant

Setting: 

Multi-center, at cancer-accredited medical centers, utilizing the National Cancer Database (NCDB).

Summary:

Ablative Therapy (AT) is progressively utilized in the treatment of inoperable and early-stage NSCLC due to well-demonstrated prolonged survival rates, however little data exists on the efficacy AT in the treatment of late-stage NSCLC. Here, the authors retrospectively reviewed overall survival among patients with stage IIIB or stage IV NSCLC who were treated with AT as the only treatment aside from chemotherapy compared to patients who did not undergo AT.

Patients who underwent any other treatment modality for NSCLC were excluded. This resulted in a total of 140,819 patients (mean age of 69 years, 54.7% male) that were included in the study, of which 249 received AT. OS between these two cohorts was then calculated from the time of diagnosis to the time of death.

The median OS for all included patients was 5.0 months. Using a multivariate cox regression the cohort receiving AT had longer OS, however this was not a statistically significant difference. Propensity matching based on demographic and clinicopathologic characteristics was performed which resulted in a statistically significant OS of 5.9 months in the AT group compared to 4.7 months in the control group.

Additional propensity matching for tumors less than or equal to 3 cm resulting in statistically significant OS of 14.0 months in the AT group compared to 4.7 months in the control group.

Commentary:

Results of this retrospective review with propensity matched groups suggests that AT prolongs OS in patients with stage IIIB or IV NSCLC compared to AT, especially when pre-treatment tumor size is 3 cm or less.

As the efficacy of AT in early stage NSCLC is well-established (2-year survival rates exceeding 90%), this important data also suggests that AT is efficacious in more advanced stages of NSCLC. Importantly, AT can offer a treatment option for patients with late stage NSCLC especially in those who are poor surgical candidate or for those whom palliative care is indicated. The increase in OS in patients who underwent AT with tumor sizes of 3 cm or less is consistent with existing literature supporting excellent outcomes in smaller NSCL tumor sizes.

Limitations in the data presented here include relatively small AT cohort size compared to total included patient size, lack of details of cause-specific mortality, possibility for selection bias in that those who received AT in the setting of advanced stage NSCLC may be patients more clinically favorable for the procedure, and lack of detail regarding the specific ablation techniques performed.


Post Author:
Demetrios Geanon
MD Candidate, Class of 2021
Rush University Medical Center

David M. Tabriz, MD
Assistant Professor
Rush University Medical Center

@DrDaveTabriz

Feasibility and Procedural Safety of alfapump System Implantation

Feasibility and Procedural Safety of alfapump System Implantation by IR: Experience from the MOSAIC Study, a Multicenter, Open-Label Prospective Study in Cirrhotic Patients with Refractory Ascites

Clinical question
Is alfapump implantation by IR technically feasible and procedurally safe?

Take away point
Alfapump placement by an interventional radiology approach is technically feasible.

Reference
Bendel, E. C., K. Sniderman, C. Shaw, R. T. Frederick, F. Wong, A. Sanyal, S. K. Asrani, P. S. Kamath, J. Capel and Z. J. Haskal (2020). "Feasibility and Procedural Safety of alfapump System Implantation by IR: Experience from the MOSAIC Study, a Multicenter, Open-Label Prospective Study in Cirrhotic Patients with Refractory Ascites." Journal of Vascular and Interventional Radiology 31(8): 1256-1262.e1253.

Click here for abstract

Study design
Multicenter prospective

Funding source
Sequana Medical 

Setting
Department of Radiology Mayo Clinic; Toronto General Hospital; Baylor University Medical Center; California Pacific Medical Center; Virginia Commonwealth University; Division of Interventional Radiology University of Virginia School of Medicine





Figure 1. The alfapump System implanted on the right side. (a) Schematic illustration. (b) X-ray image

Summary

The Sequana Medical alfapump is an implanted subcutaneous device that treats ascites by pumping peritonea l fluid into the bladder where it is excreted by voiding. The device consists of a pump component, a peritoneal catheter, and a bladder catheter. Current clinical data describes the device implantation procedure via a surgical approach. However, similar devices have been implanted by interventional radiologists. One aim of the MOSAIC trial (A Multicenter, Prospective, Open Label, Uncontrolled Feasibility Study to Assess the Safety and Effectiveness of an Automatic Low Flow Ascites Pump In Patients with Cirrhosis and Refractory or Recurrent Ascites) was to evaluate the technical feasibility and safety of alfapump implantation by interventional radiologists.

The authors evaluated 29 patients with cirrhotic refractory ascites from 6 different medical centers for procedural, periprocedural, and safety characteristics of IR alfapump implantation procedures. Technical success was 100%, defined as “the patient leaving the operating room with an implanted alfapump system that was actively pumping or pumping when activated or programed to do so”. 63% of the procedures were performed under general anesthesia and 37% were performed under local anesthesia. All patients received antibiotic prophylaxis.

83.3% of cases were performed according to the device instructions for use. The physician diverged from the instructions in five cases. The peritoneal catheter was implanted first in two instances to perform paracentesis during the procedure. Three cases presented procedural difficulty, of which two called for an additional incision for tunneling and one required a bladder catheter extension. One patient had a malfunctioning pump which was replaced during the procedure. One patient had post-op bleeding, which resolved after transfusion. The median hospital stay was 4 days.

27 patients were followed up at 3 months. One patient died secondary to cirrhosis and two patients had device explant because of cellulitis and wound dehiscence. 40 serious adverse events (SAE’s) were reported in 18 patients. Two SAE’s were classified as procedure related due to post-op bleeding and implant site abdominal pain and leakage. One patient developed bacterial peritonitis 26 days post-op, which was possibly procedure related. There were four re-interventions including one pump exchange the day of the procedure and three peritoneal catheter replacements for leaking, kinking, or dislodgment.

Overall, there was a 100% technical success rate, three procedure related SAE’s, four surgical revisions, and two explanations. The total adverse event rate was 31%. The study showed that alfapump implantation by IR is technically feasible. 

Commentary

The authors prospectively examined 29 cases of alfapump device implantation by interventional radiologists. The 100% technical success rate demonstrates that an IR approach is technically feasible. The overall adverse event rate was 31%. However, the authors described potential procedural changes such as increasing the initial pump volume and earlier pump initiation that may help to decrease adverse events related to pump pocket fluid accumulation. Nevertheless, the adverse event rate was comparable to or lower than reported in prior studies. As the authors mention, the study is limited by the small sample size, short follow up, and lack of control group. As the alfa pump device becomes more prevalent, subsequent larger studies will help further characterize the safety of an IR implantation and the risks and benefits compared to a surgical technique. Overall, alfa pump placement by interventional radiology is technically feasible and the alfa pump is a promising device for the treatment of recurrent ascites.

Post Author

Maxwell Cretcher, D.O.
Integrated Interventional Radiology Resident, PGY-4
Department of Interventional Radiology
Dotter Interventional Institute, Oregon Health and Science University
@MCretcher