Feasibility Study of “Snuffbox” Radial Access for Visceral Interventions

Summary

This report represents a feasibility study of the use of “snuffbox” radial access in the visceral interventions. “Snuffbox” radial access refers to access of the dorsal radial branch located on the dorsum of the hand between the first and second digits. Its use has been recently reported in cardiology literature for patients with limited mobility, operator positioning convenience, and for use as an alternative access due to radial artery limitations.

The authors retrospectively report 50 snuffbox accesses in 31 patients, the majority of which were for hepatic oncologic interventions. The access was performed under ultrasound guidance with a micropuncture set. A size cutoff of 16 mm was utilized for slender 5-F sheaths (48 accesses) and 20 mm for slender 6-F sheaths (2 accesses). 3,000 IU heparin were given after access as well as 200 µg of nitroglycerin at the beginning and end of the case.

Technical success rate was 100%, defined as ability to use the intended access for the visceral intervention, and there was one access site complication that required no intervention (2-mm pseudoaneurysm, self-resolving). The average vessel size was 2.1 mm, and there was a mean of 1.6 accesses per patient.

Overall, the authors found this access point to be successful. Intra-procedurally, it allowed for subjectively more ergonomic patient positioning, but the added length to the access did necessitate most cases be done with 110-cm length catheters. Hemostasis required more diligence due to the mobility of this anatomic region.



Figure 1
Access needle inserted under US guidance with a guide wire inserted. (Inset) US of the access site in the distal radial artery in the anatomic snuffbox over the trapezium.

Commentary

This report represents an early evaluation of the use of the dorsal radial artery branch (“snuffbox”) for use in visceral interventions. Radial access has increased in popularity and frequency with visceral interventions, piggy-backing on the large coronary literature. Its safety and efficacy are well documented, especially in anticoagulated patients and those necessitating early ambulation. 

 
The use of the snuffbox for access is relatively new in both the coronary and visceral angiography literature. The authors demonstrate its high technical success rate in this report. The advantages of this access are at this point theoretical. The dominant finding thus far has been a subjective increase in patient and operator preference for positioning, as the hand is not supinated for this access. Additional theoretical advantages are preservation of the palmar radial artery branch to the hand and sparing of direct access of the radial artery proper (and associated risks). 

At this point, snuffbox access has been demonstrated to be technically feasible and can be viewed as an alternative or bail-out option in the appropriate patient. Further research in larger cohorts will be necessary to allow for evaluation of the safety and efficacy for visceral interventions, especially given the proven safety and efficacy of traditional radial and femoral artery access.

Click here for abstract

Pua U, Sim JZT, Quek LHH et al. Feasibility Study of “Snuffbox” Radial Access for Visceral Interventions. J Vasc Interv Radiol. 2018; 29(9): 1276-1280.

Post Author:
Daniel P. Sheeran, MD
Assistant Professor
Department of Radiology and Medical Imaging
Division of Vascular and Interventional Radiology
University of Virginia

Operator Dose Reduction during Transjugular Liver Biopsy Using a Radiation-Attenuating Drape: A Prospective, Randomized Study

Summary

Radiation protection is a critical consideration for routine as well as complex interventional radiology procedures. The authors in this study utilized disposable, heavy metal, lead-free, radiation-absorbing surgical drapes laid over the patient during transjugular liver biopsies (TJLB). The primary outcome was operator dose equivalent (ODE), measured in microSieverts (uSv). This was measured by personal dosimeters worn at the chest level outside of lead aprons. ODE was then compared between the protective drapes and standard non-protective drapes. The authors point out several similar studies comparing dose reduction with protective drapes during nephrostomy tube placements, femoral access procedures, and coronary artery interventions. This is the only known study comparing standard and protective drapes during TJLB. A total of 60 patients were included in the statistical analysis. There were no differences in mean kerma-area product (KAP), fluoroscopy time, or number of exposures between the two groups. Ultimately, mean radiation dose incident on the operator was decreased by 56% when using radiation absorbing drapes (37 uSv versus 84 uSv, p < 0.0001). Additionally, ODE corrected for KAP was reduced in the protective drape arm (p < 0.0001). The authors have shown that using radiation-absorbing drapes during TJLB reduces operator scatter radiation as measured by a chest-level personal dosimeter.



Figure 1. Drape positioning. A square split drape was positioned around the jugular access sheath. A rectangular drape was then applied to the patient’s shoulder and body wall, partially overlapping the square drape at the access site.



Figure 4. Operator exposure data per KAP. PD = protective drape; SD = standard drape.

Commentary

While continued investigation into methods of radiation dose reduction is absolutely warranted and valuable, an element of diminishing returns should not be overlooked. Most commonly in these types of studies the method of measurement is a dosimeter worn outside of conventional lead apron shielding. While this is appropriate for modeling and comparing across studies it would be difficult to extrapolate true dose reduction given that the dosimeter is outside of the lead apron. It is important to remember that typical 0.5 mm lead apron shielding provides a significant 90% reduction in equivalent dose. Therefore the actual reduction in dose to the operator in this study is presumably much lower than 56%. That said the authors report that the cost of protective drapes for each case was $60. This is a small price to pay for radiation protection and peace of mind. Additionally, over an entire career, consistent utilization of protective drapes would certainly provide a benefit. However, consistent use of protective drapes would come with consistent costs which can add up if used for a large percentage of procedures. Ultimately, this would necessitate a departmental discussion which will vary between institutions and practices based on ideology and finances.

Click here for abstract

Ryan Kohlbrenner, MD, Evan D. Lehrman, MD, Andrew G. Taylor, MD, PhD, Maureen P. Kohi, MD, Nicholas Fidelman, MD, Vishal Kumar, MD, Miles Conrad, MD, K. Pallav Kolli, MD. Operator Dose Reduction during Transjugular Liver Biopsy Using a Radiation-Attenuating Drape: A Prospective, Randomized Study. J Vasc Interv Radiol 2018; 29: 1248-1253.

Cane Hoffman, MD, PGY-5
Department of Radiology
Wake Forest Baptist Medical Center
@WakeForest_IR

Tumor Targeting and Three-Dimensional Voxel-Based Dosimetry to Predict Tumor Response, Toxicity, and Survival after Yttrium-90 Resin Microsphere Radioembolization in Hepatocellular Carcinoma

Summary

Treatment planning systems (TPSs) have been used in external-beam radiation therapy to characterize three-dimensional dosimetry at the voxel level and to calculate radiation distribution. TPSs can be used during radioembolization (RE) of hepatocellular carcinoma (HCC) to assess the heterogeneity of distribution of 90Y in the liver with the hopes of identifying predictive factors related to tumor control and toxicity. In the current study, 45 90Y resin microsphere REs were performed on patients with Barcelona Clinic Liver Cancer stage B /C HCC and area under the dose-volume histograms (AUDVH) were calculated from post-therapy PET/CT scans to determine the volume of liver tumor targeting. The volume of the total liver (Virradiated liver), tumor (Vtumor), and nontumoral liver (Vnontumoral irradiated) treated was extracted from the TPS. Tumor control was assessed through routine follow-up multiphasic CT scans and progression-free survival (PFS), overall survival (OS), and toxicity were recorded.

Of the 42 included treatments, complete targeting of the tumor was achieved in 60% (n=25) of patients and the 6-month tumor control rate was 40.5% (n=17). Both univariate and multivariate analysis showed that complete tumor targeting and AUDVHtumor were significantly associated with tumor control with a dose threshold to predict tumor control of 61 Gy. The OS and PFS was significantly shorter in patients with incomplete tumor targeting (median OS = 4.5 months, mean PFS = 2.7 months) when compared to patients with complete tumor targeting (median OS = 19.2 month, median PFS = 7.9 months) (P < 0.001 and P < 0.001 respectively). Radioembolization-induced liver disease (REILD) occurred in 5 patients (11.9% of treatments), in which a mean dose of 78.9 Gy was delivered to the nontumoral liver. AUDVHtumor and tumor targeting using 3D voxel-based tumor dose provides a representative reflection of the dose received by the tumor and appears to be correlated with tumor control and responsiveness.



Figure 1. Example of TPS post-processing to obtain 3D voxel-based dosimetry and corresponding DVHs. (a) Baseline CT scan with manual segmentation of tumor (red), portal vein invasion (purple), and liver (yellow). We subtracted necrosis owing to previous ablation (blue). (b) 90Y PET/CT imaging. (c) Screenshot of 3D voxel-based dosimetry with isodose curves on TPS (complete tumor targeting). (d) DVHs for tumor (red), portal vein invasion (purple), nontumoral irradiated liver (orange), and whole liver (yellow).



Figure 4. Kaplan-Meier estimates. (a) PFS in patients with complete vs incomplete tumor targeting (P < .001). (b) OS in patients with complete vs incomplete tumor targeting (P ¼ .001). (c) PFS in patients depending on tumor targeting and a 61-Gy cutoff for AUDVH tumor (P < .001).

Commentary

Through the utilization of a 3D voxel-based TPS, the authors concluded that tumor targeting and dose delivered to the tumor are predictive of tumor control. This planning system accounts for the heterogenous deposition of 90Y microspheres within the liver, whereas the partition model used for activity calculations fails to account for varied compartmental uptake. While the proposed TPS adds to the body of literature that supports complete tumor targeting, there is still disagreement regarding the threshold dose required for tumor control. Individual patient characteristics will likely need to be incorporated into the prognostic tools used for predicting dose response. Further, while complete tumor targeting is an admirable goal, factors including difficult selective catheterization, extrahepatic blood supply, and the presence of contralateral lobar disease limit the ability to achieve complete tumor targeting. However, research regarding predictive factors related to HCC responsiveness to RE is critical to improve the PFS and OS of patients.

Click here for abstract

Allimant C, Kafrouni M, Delicque J, Ilonca D, Cassinotto C, Assenat E, et al. Tumor Targeting and Three-Dimensional Voxel-Based Dosimetry to Predict Tumor Response, Toxicity, and Survival after Yttrium-90 Resin Microsphere Radioembolization in Hepatocellular Carcinoma. J Vasc Interv Radiol. 2018 Sep 11;

Post Author:
Jacob Bundy, MD, MPH
PGY-1
Department of Surgery
University of Michigan Health System
@JBundyRad

Midterm Recanalization after Arterial Embolization Using Hydrogel-Coated Coils versus Fibered Coils in an Animal Model

Summary

The number of available coils on the market continues to increase with variations on the basic principle of creating a mechanical obstruction to cause occlusion. Both fibered and hydrogel-coated coils (HydroCoils) are available with the purpose of enhancing the effectiveness of the mechanical blockade. HydroCoils are well documented in neuro-interventional aneurysm coiling showing decreased recanalization rates. The purpose of this study was to evaluate the angiographic and pathologic effects of HydroCoils and fibered coils within the internal iliac arteries and renal arteries of a sheep model. Comparison time points included 1 week, 1 month, and 4 months.

0.018-inch detachable and 0.035-inch pushable HydroCoils (Azur; Terumo, Tokyo Japan) were compared with 0.018-inch detachable fibered coils (Interlock; Boston Scientific, Marlborough, Massachusetts) and 0.035-inch pushable fibered coils (Nester; William Cook Europe, Bjaeverskov, Denmark). In 12 sheep, the left internal iliac was coiled with 0.035-inch coils and the right renal artery with 0.018-inch coils. Selective angiograms were performed immediately following coil embolization, and subsequently at 7 days, 1 month, and 4 months. Pathologic evaluation was performed at 4 months. There was no statistical difference in recanalization rates at the 7 day interval. However, at one month, there was a 50% (6 of 12 arteries) occlusion rate with fibered coils compared to 100% (12 of 12) with HydroCoils. At 4-months, vessel occlusion was 25% (3 of 12) with fibered coils compared to 80% (8 of 10) with HydroCoils. In both groups, recanalization was higher in the renal arteries (occluded with 0.018-inch coils) compared to the internal iliac arteries (using 0.035-inch coils). On pathologic examination, the occlusion plug was 77% thrombus and 23% metal with fibered coils versus 36% thrombus, 15% metal, and 49% hydrogel.



Figure 3 and 4. 3) Photographs of tissue sections of 0.035-inch HydroCoils occluding an iliac artery at 4 months. Complete occlusion is visible. The coil (arrows) represented 22% of the lumen surface, the hydrogel (green asterisks) represented 51%, and thrombus (red asterisks) represented 27%. Artefactual detachments are seen around the coil loops. 4) Photographs of tissue sections of 0.035-inch fibered coils occluding an iliac artery at 4 months. Complete occlusion is visible. The coil (arrows) represented 21% of the lumen surface, and thrombus (asterisks) represented 79%. Dacron fibers are difficult to identify.

Commentary

With increasing products available for permanent embolization, including coils and plugs, there is increasing competition for utilization in specific cases and for space on your shelves. Performance, sizing choices, versatility, and cost-effectiveness are all important factors in product choice. Bare metal and fibered coils are known to have recanalization over time, likely due to clot resorption. HydroCoils were created to combat this phenomenon with the outer hydrogel polymer expanding with exposure to blood and fill a larger portion of the lumen. This is again demonstrated in this study along with decreased recanalization rates at 1 and 4 months. This study is limited due to the small number of arteries embolized (6 in each category), the nature of an animal model, and short follow up (4 months). Long term degradation of the hydrogel or adjacent inflammatory reaction may effect durability past 4 months. Additionally, cost considerations with HydroCoil use and clinical consequences of recanalization was not addressed. With future research in vivo and with increased follow up duration, HydroCoils could be proven to have superiority compared to standard bare metal and fibered coils which could have significant effect on what you choose to stock and deploy next.

Click here for abstract

Fohlen A, Namur J, Ghegediban H, et al. Midterm Recanalization after Arterial Embolization Using Hydrogel-Coated Coils versus Fibered Coils in an Animal Model. J Vasc Interv Radiol. 2018.

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

A National Cancer Database Analysis of Radiofrequency Ablation versus Stereotactic Body Radiotherapy in Early-Stage Non–Small Cell Lung Cancer

Summary

Investigators from the University of California and Sinai Medical Center compared the overall survival (OS) and rate of 30-day readmission after radiofrequency (RF) ablation and stereotactic body radiotherapy (SBRT) in patients with early-stage non–small cell lung cancer (NSCLC). Study population was extracted from the National Cancer Database (NCBB), and patients with stage 1a and 1b NSCLC treated with primary RF ablation or SBRT from 2004 to 2014 were included. Patients treated at low-volume centers, defined as facilities below the 95th percentile in volume of cases performed, were excluded. The final cohort comprised 4,454 cases of SBRT and 335 cases of RF ablation. Estimated median survival and follow-up were 38.8 months and 42.0 months, respectively. Patients treated with RF ablation had significantly more comorbidities (P < .001) and higher risk for an unplanned readmission within 30 days (hazard ratio = 11.536; P < .001). No difference in OS for the unmatched groups was found on multivariate Cox regression analysis (P = .285). No difference was found in the matched groups with 1-, 3-, and 5-year OS of 85.5%, 54.3%, and 31.9% in the SBRT group vs 89.3%, 52.7%, and 27.1% in the RF ablation group (P = .835). The authors concluded that there was no significant difference in OS between patients with early-stage NSCLC treated with RF ablation and SBRT.



Figure: Log-rank analysis of the propensity score adjusted Kaplan-Meier survival curves comparing treatment types and stratified by propensity score. The number of patients at risk is listed below each time interval. P value for the log-rank test is included. RFA = RF ablation.

Commentary

The results of this study shows that RF ablation and SBRT have similar OS for stage 1 NSCLC, in accordance to recent systematic review and other prospective studies as mentioned by the authors. Nonetheless, the rate of unplanned 30-day readmission was significantly higher in patients submitted to RF ablation. This could be explained by the presence of significantly more comorbidities in the RF ablation group (P = 0.001), but it is also likely related to the more invasive nature of percutaneous ablation compared to SBRT. Major limitations of the study were the significant sample size discrepancy between two groups, limited accuracy of data from NCDB and lack of information regarding technical procedure specifications and rate of local tumor control. However, this study provides a good insight of “real world” practice and how thermal ablation has been incorporated in the management of inoperable stage 1 NSCLC. It also paves the way for newer thermal ablative technologies such as microwave, which has the potential to improve local control by direct energy propagation, associated with less complication rates given the lower device profile.

Click here for abstract

Post Author:
Ricardo Yamada, MD
Assistant Professor
Department of Radiology
Division of Vascular and Interventional Radiology
Medical University of South Carolina

Carotid Artery Stent Placement and Carotid Endarterectomy: A challenge for Urgent Treatment after Stroke-Early and 12-month outcomes in a Comprehensive Stroke Center 

Summary

The manuscript presents the results comparing the safety, efficacy and outcomes (short term and 12 month) of patients that presented to a single major stroke center with TIA or Stroke and underwent revascularization within 7 days either with carotid artery stenting (CAS) or carotid endarterectomy (CEA).

Patients were evaluated in the acute phase by a neurologist (not involved in the study) that presented the option of CAS or CEA to the patient or family member after the diagnostic work up had identified the extracranial ICA as the source of the stroke. Revascularization criteria included a carotid lesion on the relevant side with >70% stenosis or unstable plaque with 50-69% stenosis. 110 patients were included, 62 underwent CAS and 48 CEA.

Clinical outcomes evaluated included: type of event, stroke severity, disability (evaluated at 6 time points), periprocedural and postprocedural complications. Outcome measures evaluated new onset of stroke or vascular death, neurologic worsening, brain or systemic hemorrhagic complications, functional outcome, lesion restenosis, cardiac events, cognitive symptoms, and nerve lesions.

The authors found that CAS patients had more instances of CAD and intracranial stenosis, higher ESR, had a higher number of major stroke and were treated later when compared to the CEA group.

Incidences of all complications were similar between both groups. The severity of the event showed significant treatment effect that was related to the lower severity in CEA patients. Functional improvement, survival, stroke and vascular death at 12 months were all similar between both groups.

The need for early revascularization has been documented by the decreased risk of stroke or death (6% in treated patients vs. 18.8% in non-treated patients). The authors highlight that the patients included here are representative of the population that is being evaluated in emergency departments (high proportion of stroke vs TIA). The authors point out that even though stroke severity was higher at admission and at 1 month in the CAS group, functional changes were similar to CEA patients. While the 12 month survival was similar, worse outcomes were observed in the CAS group, which could be the result of confounding factors and not the CAS procedure.

The study has some limitations: small sample size, retrospective nature and the lack of standardization of the CEA procedure. In addition, newer techniques such as Transcarotid artery revascularization with flow reversal, might influence the safety of CAS particularly in patients with plaque in the aorta and aortic arch.

The authors mention that confounding factors might have been minimized since the patients were all evaluated at a single stroke center with experienced surgeons and interventionalists.

The authors conclude that CAS proved to be equivalent to CEA in the early revascularization of patients with TIA or acute ischemic stroke (including severe stroke).



Figure- NIHSS scores across time in both CEA and CAS patients. Significant treatment effect was driven by the lower severity in CEA patients. Both groups showed improvement over time.

Commentary

This retrospective study makes a compelling argument that CAS should be considered at least equivalent to CEA in the early revascularization of patients that have suffered a TIA or stroke. While historically CEA has been considered superior, newer techniques and more technical experience have made CAS safer and more effective than the results of previous studies. This study included patients with more severe stroke (when compared to prior published studies), and found that CAS and CEA had similar survival, functional outcome, secondary stroke prevention and complication results, despite the CAS group presenting with higher severity scores and more comorbidities. This study evaluated a consecutive group of patients that closely resemble patients that present at stroke centers, and found that in the hands of experienced surgeons and IRs, the complication rates and clinical outcomes are similar. Modern techniques and more extensive experience might prove to make CAS equivalent in this patient population, and further studies are needed to validate the promising results presented in this manuscript.

Click here for abstract

Rocco A, Sallustio F, Toschi N, Rizzato B, Legramante J, Ippoliti A, Marchetti AA, Pampana E, Gandini R, Diomedi M. Carotid Artery Stent Placement and Carotid Endarterectomy: A Challenge for Urgent Treatment after Stroke-Early and 12-Month Outcomes in a Comprehensive Stroke Center. J Vasc Interv Radiol. 2018 Sep;29(9):1254-1261.e2. doi: 10.1016/j.jvir.2018.03.025. Epub 2018 Jun 21. PubMed PMID: 29935838.

Post Author: 
Carlos J. Guevara, MD
Assistant Professor
Department of Radiology, Interventional Radiology Division
University of Texas Health Sciences, Houston
@UTHouston_IR
@CarlosGuevaraIR

First-in-Man Experience with a Novel Catheter-Based Renal Denervation System of Ultrasonic Ablation in Patients with Resistant Hypertension

Summary

Hypertension that is resistant to medical management (including at least three antihypertensive medications, including an anti-diuretic) is termed resistant hypertension. Sympathetic control of blood pressure is noted to have significant effect on blood pressure, and since the attempts of sympathectomy many decades ago, it has been posited that denervating this system may be an effective treatment for the severe hypertension these patients suffer with. There was considerable promise for percutaneous renal artery denervation with radiofrequency (RF) energy in initial non-US trials approximately 10 years ago, however the final US randomized trial failed to show benefit of the procedure compared to sham interventions (Simplicity HTN-3). Since that time, there has been a reappearance of efforts to evaluate renal nerve denervation (RDN) with new modalities.

The authors of manuscript describe their experience with RDN using use a 6-French TIVUS (Cardiosonic Ltd, Tel Aviv, Israel) catheter, which is an ultrasound-based catheter that can be placed in the renal artery without use of balloon occlusion. This first in man technique study is a prospective, multicenter, non-randomized, open-label clinical study consisting of three cohorts: Severe Resistant Hypertension (>160mmHg systolic in non-diabetic, >150mmHg in diabetic), Moderate Resistant Hypertension (>140mmHg systolic in non-diabetic, >130 in diabetic), and Failed RF Therapy (>150mmHg systolic in diabetic, >140mmHg in diabetic). Selection of patients was based on Office based blood pressures at 2 visits and 2-week home pressure monitoring, followed by 24-hour ambulatory blood pressure monitoring. If these were consistent with resistant hypertension, patients underwent screening renal angiography to ensure anatomical suitability, and then ultimately had RDN with either Unidirectional or Multidirectional catheters. Patients were followed for 6 months in clinic, which was the endpoint based on the commercial sponsor limitations. A total of 39 patients were enrolled, 20 of which had isolated systolic hypertension, and the remainder with combined systolic and diastolic hypertension. Two patients had prior RF denervation, now with recurrence of resistant hypertension. The authors found a mean reduction (-30mmHg systolic and -14mmHg diastolic) in blood pressure over the course of 6-month follow-up. The subsets of patients with the highest BP reduction included diabetics, those with combined systolic and diastolic hypertension and the patients who underwent multidirectional catheter denervation. There were no major adverse events and 6-month ultrasounds were normal in all patients.

Commentary

Options for patients with primary resistant hypertension are limited, and although prior denervation-based treatments were derailed by the anticipated 2009 Simplicity-HTN3 trial’s failure to show benefit, the resurgence of multi-modality denervation studies are promising. This study demonstrated significant improvement in cohorts of patients, which can help future studies in patient selection. The limitation of only 6 months of study related follow-up was discussed by the authors, which needs more prolonged follow-up to ensure durability of the results. Additionally, although treatment benefit was shown in patients with recurrent disease despite prior denervation may be considered a source of bias, the finding that they responded could be considered a potential benefit that should be explored. Lack of this being a randomized, blinded study blinded is a limitation however this study alludes to safety and efficacy of this reiteration of RDN, providing a positive outlook for future trial development.

Click here for abstract

Chernin G, Szwarcfiter I, Scheinert D, Blessing E, Diehm N, Dens J, Walton A, Verheye S, Shetty S, Jonas M. First-in-Man Experience with a Novel Catheter-Based Renal Denervation System of Ultrasonic Ablation in Patients with Resistant Hypertension. J Vasc Interv Radiol 2018; 29:1158-1166.

Post Author:
Kumar Madassery, MD
Assistant Professor, Vascular & Interventional Radiology
Director, Advanced Vascular & Interventional Radiology Fellowship
Rush University Medical Center, Chicago IL
Rush Oak Park Hospital, Oak Park IL
Twitter: @kmadass, @vir_rush

Comparison of Stable and Unstable Ethiodized Oil Emulsions for Transarterial Chemoembolization of Hepatocellular Carcinoma: Results of a Single-Center Double-Blind Prospective Randomized Controlled Trial

Summary

This is a prospective single-center double-blind randomized control trial evaluating the safety and efficacy of two embolic mixtures for conventional TACE, one with a stable water-in-oil mixture, and one with an unstable mixture. The study authors enrolled 812 patients over a 5-year period and were blinded to the type of chemoembolic administered in the setting of locoregional therapy for patients with hepatocellular carcinoma.

The embolic technique and type was the premise of this study. Thus, it should be noted that the stable water-in-oil mixture was 50 mg epirubicin / 50 mg lobapatin / 6 mg mitomycin C mixed with 4 mL of solvent (5:1 Iopamidol 300 contrast : Distilled water) and 12 mL ethiodized oil; the unstable water-in-oil mixture was identical except for having 4 mL of distilled water as the solvent (no contrast dilution). This mixture was emulsified for 10 minutes on a test-tube shaker at 1,000 rpm prior to administration.

Once enrolled, patients stayed within that treatment arm but were allowed to undergo additional treatments to include if needed repeat chemoembolization (type not specified by the authors). The study follow-up ended 12-months after enrollment of the last patient. The primary endpoint was overall survival, and the authors saw no significant difference between treatment arms. In addition no difference was observed in tumor response, time to progression, or adverse events. They did note a significant increase in myelosuppression in those patients who received the unstable water-in-oil chemoembolic.

The authors also evaluated the peripheral plasma concentration of epirubicin following TACE in a small subset of patients, finding the peak concentration to be higher in the unstable mixture but with a similar AUC. They also conducted in vitro analyses of solution stability for both epirubicin with solvent (5:1 contrast:water felt most stable and matched specific gravity of ethiodized oil) and epirubicin solution with ethiodized oil (1:3 most stable and uniform).

Commentary

This study is useful given its prospective nature and large size in comparing different techniques for use in conventional TACE. The authors found no significant difference in treatment effects between the two arms. However, they did note differences in myelosuppression and peak epirubicin plasma concentrations with the unstable solvent, suggesting that a more stable chemoembolization solution may help with keeping the drug local in the liver. The in vitro analyses they performed also suggest similar results. Limitations with this study are that it may be hard to duplicate the administered embolic in clinical practice given available medications and contrast agents at one’s institution. Also, the practicality of using a test-tube shaker to achieve a uniform solution may be difficult depending on the clinical scenario. At the very least, this study serves as a baseline for the putative ideal conventional TACE chemoembolic solution, with regard to stability and uniformity of embolics.

Click here for abstract

He, M., Zou, R., Wei, W., et al. Comparison of Stable and Unstable Ethiodized Oil Emulsions for Transarterial Chemoembolization of Hepatocellular Carcinoma: Results of a Single-Center Double-Blind Prospective Randomized Controlled Trial. J Vasc Interv Radiol. 2018; 29(8): 1068-1077.

Post Author:
Daniel P. Sheeran, MD
Assistant Professor
Department of Radiology and Medical Imaging
Division of Vascular and Interventional Radiology
University of Virginia

Percutaneous Cryoablation of Solitary, Sporadic Renal Cell Carcinoma: Outcome Analysis Based on Clear-Cell versus Papillary Subtypes

Summary

With the increasing drive towards individualized cancer care it has become imperative that we understand variation in treatment response patterns to loco-regional therapies, based on the different tumor biology and subtypes.

Percutaneous renal ablation has proven to be a robust locoregional therapy for management of T1a renal tumors however very little is known about variation in oncologic response/benefits based on tumor subtypes. Researchers from Mayo clinic Rochester, Minnesota recently published a retrospective review/analysis of their outcomes of percutaneous renal cryoablation of T1a tumors based on clear cell vs papillary subtypes.

They reviewed 173 treated patients from a single center renal cancer registry with T1a tumors over a 13-year period. Three quarters of the patients had clear RCC and the rest papillary RCC – biopsies were performed prior to or during the cryoablation.

Recurrence rate was higher with cRCC (4 %) vs pRCC (0 %). The 5 yr progression free survival was higher with pRCC (100 %) vs cRCC (88 %). Clear cell RCC had a higher bleeding complication rate (5.2%) vs (0)%. Although none of these findings had statistically significant p values, the trend from these data is interesting.

Commentary

The paper asks a very pertinent question about variation of renal tumor response to minimally invasive percutaneous cryoablation. This is important in the era of personalized cancer care. By better understanding the variations in tumor response outcomes for T1a renal tumor we could potentially move towards personalizing the post cryoablation surveillance /follow up protocol based on the tumor type. Although this is promising and exciting, there remains a paucity of studies to address this issue, therefore further robust Level 1 studies are required before we can carve out clear evidence driven guidelines for personalizing the post treatment surveillance/follow up imaging.

The paper reaffirms that biopsy is the lynch pin of this new paradigm, therefore it is imperative to perform a biopsy of the renal masses especially as multiple studies including this current study now show a relatively low complication rate for renal mass biopsy. Whether it should be performed before treatment to guide therapy or during the ablation remains controversial. The authors provide their opinion on this matter in the paper.

There are several weakness’ in the paper which are acknowledged by the authors. The main weakness to highlight is that although they were interesting trends suggested by the data, none of the measure variables reached statistical significance. This is likely due the study being inadequately powered to demonstrate the statistical significance. Further pooled data and larger studies are required to address this.

Post Author:
Rodrick C Zvavanjanja MD, MSc, FRCR, DABR(VIR/DR)
Assistant Professor
Department of Diagnostic and Interventional Radiology
University of Texas at Houston McGovern Medical School
@RodZvavanjanja