Need more help in the IR suite?

If you feel like you need more ancillary support in the IR suite, but haven’t been able to convince your administrators, you’re in luck. The Society of Interventional Radiology (SIR) Standards Division Committee has just published the results of their survey on the status and physician opinion regarding ancillary staffing for the IR suite. After receiving responses from over 700 physicians, the workgroup found that staffing is not deficient based on American College of Radiology (ACR) guidelines. However, physicians remain dissatisfied. This may be due to the ACR guidelines lacking consideration of procedure complexity or the availability of scrubbed assistants. During weekends or off-hours, staffing and access to anesthesia support were felt to be inadequate by the respondents.

This important survey serves as the first step in creating evidence-based guidelines on IR suite staffing. Until additional investigations can be completed, this report can be used as an important tool for physicians negotiating for more staff.


Click here to see the full abstract




Numbers of procedure rooms in the operator’s primary setting.




Circumstances under which anesthesia service support is routinely used at the respondent’s institution.


Citation: Natcheva, H. N. et al. Survey of Current Status and Physician Opinion Regarding Ancillary Staffing for the IR Suite. Journal of Vascular and Interventional Radiology 25, 1777–1784 (2014).


Post author: Amish Patel, MD

Complications associated with strut penetration in Celect filter

Strut penetration associated with Celect filter placement is a known entity. Researchers from the University of Chicago retrospectively evaluated patients who had an abdominal CT performed following Celect filter placement. The present study demonstrated strut penetration rate of 28.5% that was positively associated with indwelling time longer than 100 days. Strut penetration was defined as a filter leg extending >3mm beyond the IVC wall. Despite strut penetration, researchers saw no evidence of associated breakthrough PE or retrieval failure.

Comments:

The analysis of the presence and effects of strut penetration is limited in this study as only a subset of filter recipients had an abdominal CT performed and the true clinical impact of strut penetration was not evaluated. However, the paper is noteworthy demonstrating no association between rate of strut penetration and breakthrough PE, local complication, or retrieval failure.


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Strut penetration in a 44-year-old female patient with back pain. (a) Image from a contrast-enhanced CT shows right hydronephrosis. (b) A more caudal image from the same CT examination demonstrates strut compression of the proximal right ureter (arrow). The filter was successfully removed, and a suprarenal filter was placed. 

Citation: Bos, A. et al. Strut Penetration: Local Complications, Breakthrough Pulmonary Embolism, and Retrieval Failure in Patients with Celect Vena Cava Filters. Journal of Vascular and Interventional Radiology (2014). doi:10.1016/j.jvir.2014.09.010


Post Author: Luke Wilkins, MD

Pedal Access for Revascularization of Infrainguinal Occlusive Disease

While treatment of endovascular revascularization in CLI is an effective method to achieve limb salvage, technical success and amputation-free survival vary widely. However, in a patient that fails antegrade recanalization in whom bypass options are nonextistent, a retrograde approach from a pedal access may be a viable option. Researchers from the University of Virginia presented their experience with pedal access in 99 limbs. Technical success was achieved in 89% of patients with a majority involving subinitimal recanalization. The limb salvage rate for technically successful cases was 74% at 6 months, 64% at 12 months, and 55% at 24 months.

Comments:

This study is one of the largest series of pedal access cases and shows a high technical success rate in a challenging patient population. While limb salvage rates are not ideal, the study was limited by premature amputations and revascularization to achieve tissue healing for a pre-planned amputation.


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(a) Digital subtraction angiography shows occlusion of the distal popliteal artery (black arrow) and reconstitution of the anterior tibial artery (white arrow). (b) Retrograde access is obtained using a micropuncture needle (arrow). (c) A through-and-through flossing guide wire is established by advancing the retrograde wire (white arrow) through the end hole of the antegrade catheter (black arrow) via a retrograde 3-F catheter (arrowheads) as a support catheter. (d) Completion angiogram after angioplasty shows in-line patency of and to the anterior tibial artery (arrows).


Citation: Sabri, S. S. et al. Retrograde Pedal Access Technique for Revascularization of Infrainguinal Arterial Occlusive Disease. Journal of Vascular and Interventional Radiology (2014). doi:doi: 10.1016/j.jvir.2014.10.008


Post Author: Luke Wilkins, MD

Covered verses uncovered stents for malignant common bile duct obstruction, which lasts longer?

The often taught convention that covered biliary stents stay open longer than their bare relatives may not be true. Researchers from Seoul, South Korea are challenging this, finding that uncovered stents had significantly longer patency in their subjects. Although limited by a small sample size of 20 patients in each arm, this prospective randomized study found that the uncovered stents had a mean patency of 413 days, double that of the covered ones at 208 days.

Covered stents were always thought to have better patency because of their ability to avoid tumor ingrowth, a theory that was previously supported by several randomized studies. After finding the opposite, the authors of this study theorize that pores on the surface of the covered stent act to promote bacterial colonization and biofilm development, in turn leading to slower bile flow. Nevertheless, the authors found no survival benefit for either stent.


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Kaplan-Meier graph showing cumulative stent patency. Cumulative stent patency was significantly higher in the uncovered metallic stent versus the covered metallic stent group (P = .041, log-rank test).




Stent occlusion by sludge. (a) Percutaneous cholangiography performed after 10 mm × 80 mm Niti-S covered stent placement. The stent is not yet fully dilated. (b) Cholangiography performed 2 months after stent placement showed multiple filling defects (arrows), suggesting debris. Debris and food material were confirmed by saline irrigation.


Citation: Lee, S. J. et al. Comparison of the Efficacy of Covered versus Uncovered Metallic Stents in Treating Inoperable Malignant Common Bile Duct Obstruction: A Randomized Trial. Journal of Vascular and Interventional Radiology (2014). doi:doi: 10.1016/j.jvir.2014.05.021


Post author: Amish Patel, MD

Robot-assisted fibroid embolization

Researchers from London, UK have recently published their early experience with the Magellan robotic catheter for use during uterine artery embolization. The 9-French outer diameter system has a multidirectional bending 6-F leading catheter that is used to catheterize vessels while the operator is seated in the control room, away from ionizing radiation. Where I trained we had something like this, but we were called “fellows” and not “robots.”

The system was used in 5 women with heavy bleeding during menstruation, four of which had fibroids and one that had adenomyosis. All procedures were technically successful and without major or access site complications. Median procedure time in this study was no different than previously published times, but median fluoroscopy time compared favorably to that in the literature for the conventional technique. Based on this early experience, the authors conclude that the use of the Magellan system in uterine artery embolization is feasible and safe.

However, don’t rush to throw your apron into the trash. Although the system can accept a microcatheter in place of a 0.035” wire, the wire manipulator is not currently compatible with microcatheters. So, if you get this system in your angiosuite sometime soon, you’ll still have get up and steer the microcatheter the old-fashioned way . . . or get your fellow to do it.


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The Magellan workstation




(a, b) The SmartMask function was employed to facilitate cannulation of the right internal iliac artery. Fine movements of the leader tip were then used to direct the microcatheter into the uterine artery.

Citation: Rolls, A. E. et al. Robot-Assisted Uterine Artery Embolization: A First-in-Woman Safety Evaluation of the Magellan System. Journal of Vascular and Interventional Radiology (2014). doi:doi: 10.1016/j.jvir.2014.05.022


Post author: Amish Patel, MD

Meta-Analysis of Infrapopliteal Atherosclerotic Disease Treatment Shows Added Benefit with Drug-Eluting Stent Placement

There have been many advances in the treatment of critical limb ischemia, however, optimal management and factors affecting short and long-term procedural success have not been clearly elucidated. The authors performed a meta-analysis of 42 studies representing 3,660 unique patients. While the analysis focused primarily on short-term outcomes with a very heterogenous set of procedural and research methodologies, the manuscript found significant, device-dependent, differences. Technical success rates were higher with bare metal stents and drug-eluting stents than with atherectomy or percutaneous transluminal angioplasty. Further, DES use had higher primary patency rates than atherectomy, BMS, and PTA. In addition, the 30-day rate of TLR was significantly higher with PTA (8.1%) than with BMSs (2.2%; P < .05) and DESs (1.1%; P < .05).

Comments: 

While this study is limited due to a variety of factors, the analysis was surprising in the significant, device-dependent, differences that could be identified. While further research is necessary, the results support the use of DES in the setting of infrapopliteal disease to improve technical success, primary patency, and TLR rates.


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Artist rendition of a drug-eluting stent, reproduced via Vankatesh et al: http://www.slideshare.net/quizzito/bioabsorbable-drugeluting-cardiac-stent-analysis


Citation: Razavi MK, Mustapha JA, Miller LE. Contemporary Systematic Review and Meta-Analysis of Early Outcomes with Percutaneous Treatment for Infrapopliteal Atherosclerotic Disease. J Vasc Interv Radiol, 25 (2014) 1489-96.


Post author: Luke Wilkins, MD

New Study Examines the Effectiveness of Collateral Vein Embolization for Non-Maturing Fistulas

Failure of a new arteriovenous fistula (AVF) may be defined as an unsuitable access site 3 months after creation. While most commonly this may be treated by balloon angioplasty, collateral vein embolization (CVE) is touted to promote maturation of a non-maturing AVF. Researchers from the University of Chicago evaluated 56 embolizations in 42 patients. The majority of patients treated by collateral vein embolization (76%) progressed to fistula maturity. In 79% of patients, this was done without angioplasty, contradicting the argument that collateral veins reflect venous outflow obstruction and do not, by themselves, indicate a true 'accessory' venous pathway. In addition, the study showed a trend toward higher rates of fistula failure in patients treated with radiocephalic fistulas undergoing CVE and PTA; however, the results were not statistically significant. Of note, fistula age, vessel, size, and number of collaterals did not correlate with the rate of fistula failure or success.

Comments: 

While this study is limited by lack of objective criteria for CVE and patient sample size, the results are compelling. Unlike prior studies investigating CVE, the number of CVE procedures performed in the absence of PTA in the present study makes for a strong argument that collateral veins may represent true accessory drainage pathways that return blood to the right atrium and prevent arterialization of the target outflow vein. While more research is warranted, one may consider incorporating more aggressive treatment strategies in the setting of a non-maturing fistula.


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(a) Digital subtraction angiogram in a 67-year-old man with new brachiocephalic fistula referred for fistula immaturity. Angiogram of the fistula demonstrates a large collateral vein arising from the primary venous outflow (arrow) without other diagnostic abnormality. This vessel was subsequently selected, and embolization was performed with four 0.035-inch, 8-mm pushable coils. (b) Postembolization image after CVE no longer demonstrates opacification of the collateral vessel.


Citation: Ahmed O, Patel M, Ginsburg M, Jilani D, Funaki B. Effectiveness of Collateral Vein Embolization for Salvage of Immature Native Arteriovenous Fistulas. J Vasc Interv Radiol 2014.


Post author: Luke Wilkins, MD

Laboratory investigation: Resorbable microsphere for transient uterine artery occlusion

Researchers from France have recently developed a new kind of embolic, one that aims to ensure full and constant recanalization of the embolized artery. The most widely used embolics at this time degrade over several months, inciting chronic changes in the embolized vessel and organ. Previous animal models have shown that even after partial recanalization of the uterine artery, both fertility and birthweight are lowered. Remodeling of vessel walls can inhibit important dilatation of the uterine artery that occurs during pregnancy. A resorbable microsphere would occlude the vessel for a short time and achieve ischemia of a fibroid, but would subsequently be completely eliminated before the onset of a chronic response.

To show this, the authors embolized the uterine arteries of sheep using either their newly designed resorbable microspheres comprised of trisacryl-gelatin or traditional nonresorbable microspheres. At 7 days after embolization, an angiogram was performed to evaluate vascularity and the sheep were sacrificed to allow histologic evaluation of their arteries and uteri.

The study found that the resorbable microspheres disappeared and the arteries recanalized within 7 days in all of the sheep, something that was observed in only half of uterine arteries embolized with nonresorbable microspheres. Changes to the uterine tissue were observed to be similar. This exciting technology is yet to be tested in a large cohort, in a fibroid uterus, or in a human.


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Example of full UA recanalization and complete parenchyma opacification after embolization with REM. (a) Angiogram obtained before embolization. UA (arrow) and parenchyma (star) are opacified. (b) Angiogram obtained 10 minutes after embolization. Flow is interrupted at the level of the descending UA (arrow). (c) Angiogram obtained 7 days after embolization. Opacification of UA and its branches (arrow) at arterial phase. (d) Angiogram obtained 7 days after embolization. Opacification of parenchyma (star).


Citation:  Verret, V. et al. A Novel Resorbable Embolization Microsphere for Transient Uterine Artery Occlusion: A Comparative Study with Trisacryl-Gelatin Microspheres in the Sheep Model. Journal of Vascular and Interventional Radiology (2014)


Post author: Amish Patel, MD

Radiofrequency ablation of renal cell carcinomas: outcomes and predictors of efficacy

With the incidence of RCC on the rise, ablative techniques have become more commonplace. However, the existing body of literature is limited by studies that are small in size, have varied ablative techniques, or lack pathology of the lesion (benign vs. malignant). By retrospectively evaluating 100 path-proven RCCs treated with percutaneous RFA only, researchers at UCLA have aimed to better understand predictors of successful treatment and outcomes of RF ablation of RCCs.

By using the RENAL nephrometry score, a tool for standardizing the description of renal masses, the authors sought to determine which tumor characteristics were most predictive of treatment success. This tool is comprised of five components, Radius, Exophytic/Endophytic, Nearness of tumor to collecting system or sinus, Anterior/Posterior, and Location relative to polar lines. The authors found that the overall RENAL score predicted the ability to achieve complete tumor ablation after one session with no evidence of local tumor progression on follow-up imaging. Of the RENAL score components, Radius (size) and Location correlated with successful outcome.

At a follow-up of 2.1 years, the authors found an overall 95% success rate in treating these tumors, although 9% of tumors required a second ablation to obtain a complete response. 98.7% of patients remained free of metastasis and no patient died as result of their RCC, figures which are consistent with existing data. Although other ablative techniques are gaining popularity, RF remains the most proven modality for the treatment of renal cell carcinoma.


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USEFUL LINK: RENAL Nephrometry Score Calculator (http://www.nephrometry.com)


Citation: McClure, T. D. et al. Intermediate Outcomes and Predictors of Efficacy in the Radiofrequency Ablation of 100 Pathologically Proven Renal Cell Carcinomas. Journal of Vascular and Interventional Radiology (2014).


Post author: Amish Patel, MD

Researchers investigate new methods for dose quantification following Y-90 using PET/CT

Hepatocellular carcinoma is often managed using a lobar arterial injection of Yttrium-90 radioembolization therapy. This study describes the use of PET-CT to localize and quantify the dose after glass microsphere Y-90 therapy. This retrospective single institution study looked at 64 post-radioembolization “dose maps” created from reconstructed PET-CT images. Contouring of the liver parenchyma and tumors (using pre-procedure imaging if needed) was performed and aligned with these dose maps. A total of 113 tumors were evaluated with an average size of 4.8 cm ±4. The average tumor dose was 173 Gy ±109 and the average non-tumor liver parenchyma dose was 93.4 Gy ±32.6. The calculated average tumor-to-parenchyma dose ratio was 2.2, which suggested a preferential Y-90 uptake within the tumors.

Comments:

The authors were able to characterize the dose deposition of Y-90 in a large cohort of HCC patients being treated using the recommended dose administration algorithms. The study quantifies the well-known, extremely heterogeneous microsphere deposition and highlights the error of applying broad dosing guidelines to all patients. This imaging technique is a valuable tool for any study looking to optimize dosing and clinical response and should be considered for future research studies evaluating the wide discrepancies between dosing and deposition.


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Citation:  Lea WB, Tapp KN, Tann M, et al. Microsphere Localization and Dose Quantification Using Positron Emission Tomography/CT following Hepatic Intraarterial Radioembolization with Yttrium-90 in Patients with Advanced Hepatocellular Carcinoma. J Vasc Interv Radiol (2014)


Post author: Nicholas Hendricks, MD

Minimally invasive therapy for prostate enlargement provides alternative to surgical or endoscopic treatment

Benign prostatic hyperplasia (BPH) affects as many as 90% of all men aged 70-89 years and leads to over 4 million annual doctor visits resulting in over 1 billion dollars in direct healthcare costs annually. Patients with moderate to severe symptoms related to BPH and in whom medical therapies fail are typically treated with transurethral resection of the prostate (TURP) or prostatectomy.

In 2010, Prostate Artery Embolization (PAE) was first described to diminish blood supply to the prostate and reduce its size. The clinical trials and the science backing PAE are explored in the September edition of the Journal of Vascular and Interventional Radiology. A number of studies reviewed in this JVIR consensus paper validate the efficacy of PAE in reducing urinary symptoms from BPH. When compared in a head-to-head study with TURP, both methods showed similar efficacy, with PAE providing the advantage of less bleeding and lower rates of urinary catheterization. PAE also does not require general anesthesia, imparts little pain, and is associated with minimal blood loss. While the authors note that PAE can be technically challenging to perform, quality of life scores following PAE show that patients are quite satisfied with the symptomatic relief that PAE provides when performed successfully. The authors conclude that current data regarding PAE shows promise.

Comments: 

The present article provides the foundation that PAE appears safe and efficacious based on short-term follow-up and is best performed by an Interventional Radiologist. Further, the SIR supports the performance of high-quality clinical research to expand the numbers of patients studied, to extend the duration of follow-up, and to compare the PAE procedure against existing surgical therapies.


To see the article in its entirety free of charge, click here.


To listen to a JVIR podcastinterview regarding this work, click here or visit JVIR on iTtunes.

(a) Coronal T2-weighted MR image of the prostate demonstrates heterogeneous nodular enlargement of the central gland, with impingement on the bladder neck secondary to median lobe hypertrophy (black arrow). (b) Selective angiography of the left prostatic artery (white arrow) shows an enlarged prostate gland with increased vascularity in the central gland. (c) Coronal reformatted image from cone-beam CT after left prostatic artery injection depicts near-homogenous perfusion of the left hemiprostate (black asterisk), without evidence of potential nontarget embolization. (d) Angiogram after embolization to a target endpoint of near-stasis shows a lack of significant parenchymal perfusion.


Citation:  McWilliams, J. P. et al. Society of Interventional Radiology Position Statement: Prostate Artery Embolization for Treatment of Benign Disease of the Prostate. Journal of Vascular and Interventional Radiology 25, 1349–1351 (2014).


Images: Bagla, S. et al. Early Results from a United States Trial of Prostatic Artery Embolization in the Treatment of Benign Prostatic Hyperplasia. Journal of Vascular and Interventional Radiology 25, 47–52 (2014).


Post author: Austin Bourgeois, MD

New study evaluates factors predicting restenosis in arteriovenous fistulas undergoing intervention

Maintaining long-term hemodialysis access continues to be a challenge in patients with end stage renal disease. Stenosis of native AVFs secondary to neointimal hyperplasia is the most common cause of poorly functioning AVFs and angioplasty is the preferred treatment. This retrospective study aimed to determine predictors of primary and secondary patency after balloon angioplasty of native AVFs. Patient demographics, vasoactive medications, AVF/lesion characteristics, and biochemical data from 207 patients undergoing their first angioplasty of a native AVF were analyzed to determine predictors of AVF patency. An average of 2.2 interventions was performed per patient. Upper arm AVFs, AVFs less than 6 months old, multiple stenoses, and degree of pre procedural stenosis were significantly associated with a shorter time to fistula restenosis or thrombosis. A history of a previously abandoned fistula was the only identified risk factor for post intervention secondary patency loss. Systemic factors such as patient comorbidities, metabolic and inflammatory markers, and vasoactive medication usage did not affect primary patency.

Comments:

This is one of the largest studies to date looking at factors predicting shorter interval restenosis of AVFs postangioplasty. Multiple stenoses was identified as a risk factor for the first time. Unlike prior, smaller studies, pre procedural degree of stenosis was associated with an increased risk of post intervention primary latency loss (HR 1.3 per 10% increase). With these findings, one may consider incorporating more intensive monitoring of fistula function into their treatment algorithm when encountering a lesion with a high degree of stenosis.


Click here to see to the full abstract


Citation:  Neuen, Brendon L., et al. Factors Associated with Patency Following Angioplasty of Hemodialysis Fistulae. J Vasc Interv Radiol 2014: 25:1419-1426.


Post Author: Menaka Nadar, MD

Endovascular therapy to reduce gastric “hunger hormone”

Collaborative researchers from Johns Hopkins and Duke University Medical Centers performed a new therapy known as “bariatric embolization” on 6 swine in a recent study published in the January edition of JVIR. The authors cited the growing obesity epidemic in the United States and relatively high morbidity associated with bariatric weight loss surgery as the stimulus for their investigation.

Their study found a 30% reduction in the ghrelin-immunoreactive cell density in the gastric fundus of pigs that underwent bariatric embolization via the gastric artery with 4-6 mL of diluted 40-µm calibrated microspheres compared to 6 control swine treated with normal saline. A trend toward increased stomach fibrosis (P = .07) was also found in the treated swine, as well as stomach ulcers in half the treatment subset.

This study sheds light upon the impact of bariatric embolization on stomach hormone production and supports the scientific basis for bariatric embolization as a minimally invasive weight loss therapy. The authors are currently planning to begin the first US clinical trial of bariatric embolization on humans this summer at Johns Hopkins Hospital.


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Immunohistochemical staining of the gastric fundi (×100) and duodena confirms a significant reduction in the ghrelin-immunoreactive cell density in the gastric fundus after embolization. There is no compensatory upregulation of ghrelin-expressing cells in the duodena of treated animals.


Citation:  Paxton, B. E. et al. Histopathologic and Immunohistochemical Sequelae of Bariatric Embolization in a Porcine Model. Journal of Vascular and Interventional Radiology 25, 455–461 (2014).


Post author: Austin Bourgeois, MD