Bland Embolization as a Bridge to Transplantation

In the latest issue of JVIR, researchers from Duke evaluated the effectiveness of bland embolization as a bridge to transplantation in 117 patients with HCC that underwent treatment while within Milan criteria. Superselective embolization was performed in 128 of 181 procedures. PVA particles were the most common embolic used (132 of 181) with sizes ranging from 150-250 µm (n=111), 45-150 µm (n=16), and 250-355 µm (n=1). 40 µm embozene and 100-300 µm embospheres were also used in some procedures. Follow-up imaging was evaluated to determine if patients progressed beyond Milan criteria in an intent-to-transplant analysis. They found that post-embolization, 87% and 78% of patients still fell within Milan criteria at 6 and 12 months respectively. The median time to disease progression beyond Milan criteria was 22.6 months (95% confidence interval, 16.2-29 mo). 34 of 117 (29%) had eventual transplant at a median of 3.3 mo (range, 0.5 – 20.9 mo). The authors concluded that bland embolization has a comparable efficacy versus other embolotherapies as a bridging strategy to maintain HCC within Milan criteria.

Commentary:

A large portion of centers use TACE as the preferred noncurative locoregional treatment when surgical resection or locally ablative therapies are not feasible or as a bridge to transplantation. This manuscript is yet in another series of papers showing that there is a lack of evidence of superiority of chemoembolization versus bland embolization in prolonging survival. There is a significant increase in rate of adverse events when perform TACE versus TAE in addition to an increase in overall cost of the procedure. Given these factors, an article supporting bland embolization as a bridge to transplantation is noteworthy. While there are several limitations of the current study (multiple different embolic agents, no defined criteria for using TAE versus TACE, and a small number of patients going on to receive transplant)​ the results are an argument for bland embolization even if reserved for patients thought likely to receive a transplant if kept within Milan criteria.

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Hodavance MS, Vikingstad EM, Griffin AS, Pabon-Ramos WM, Berg CL, Suhocki PV, Kim CY. Effectiveness of transarterial embolization of hepatocellular carcinoma as a bridge to transplantation. J Vasc Interv Radiol 2016; 27:39-45.

Post Author:
Luke R. Wilkins

Cutting balloon angioplasty shows no benefit when compared to high pressure balloon inflation for de novo lesions

Recent research from the University of Ottawa calls into question the use of cutting balloon angioplasty in the treatment of de novo stenosis within autogenous fistulae for hemodialysis. 39 patients were included in this randomized controlled trial with vessel sizes ranging from 4-8 mm in diameter. The regions treated included juxtaanastomotic (38%), perianatomotic (38%), midcephalic (9%), and cephalic arch (14%). Stenoses greater than 50% were randomized to high-pressure balloon inflation versus cutting balloon. For the high-pressure balloon arm, a Blue Max balloon (Boston Scientific, Natick, Massachusetts) with a rated burst pressure (RBP) of 20 atm or a Conquest balloon (Bard Peripheral Vascular, Tempe, Arizona) with an RBP of 26–30 atm was inflated twice for 20-30 sec until the waist was effaced of the max RBP was achieved. For the cutting balloon arm, an appropriately sized 20 mm cutting balloon (Flextome; Boston Scientific) was inflated until the waist was effaced or the max RBP (10 atm) was reached. Technical success was achieved in all patients. Mean follow-up was 8.5 mo. At 3, 6, and 12 months, the postinterventional primary patency rates for the cutting balloon group were 61.1%, 27.7%, and 11.1%, respectively, compared with 70.0%, 42.1%, and 26.3%, respectively, for the high-pressure balloon group (P < 0.3 at each interval). At 48–72 hours after angioplasty, there was no difference in mean flow rate in the cutting balloon group versus the high-pressure balloon group. At the end of the study period, no patients with followup in either group exhibited unassisted patency. The only procedure-related complication was a contained vessel rupture in the cutting balloon group resulting in the formation of a 1.8-cm aneurysm that did not require any treatment and remained stable on follow-up. The authors concluded that there is no significant difference in postintervention primary patency rates when comparing high pressure and cutting balloon angioplasty.

Commentary:

This interesting manuscript calls into question the assumption that using a cutting balloon can provide better patency by reducing barotrauma injury to the vessel wall. While there have been prior RCTs comparing cutting balloon to high pressure balloon inflation, the present study includes more defined patient selection criteria and includes longer follow-up while adhering to SIR reporting guidelines. However, several limitations remain including sample size and highly selective inclusion criteria. Further, the current study evaluates the use of cutting balloon on de novo lesions that have not undergone treatment in the past. While this methodology most effectively studies the true patency of cutting balloon versus high pressure balloon and may discredit the theory that decreased barotrauma of cutting balloon allows improved patency, it may not accurately reflect the current most common use of this tool for the interventionalist. Often times, one may use the cutting balloon on lesions resistant to balloon inflation or with residual, hemodynamically significant narrowing despite adequate waist effacement. In this setting, recent studies have suggested superiority in primary and secondary target lesion patency when compared with high-pressure balloon inflation (2). Depending on your practice pattern and current approach to de novo lesions, this manuscript may affect your treatment algorithm for stenotic lesions in AVFs.

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1. Rasuli P, Chennur VS, Connolly MJ, et al. Randomized trial comparing the primary patency following cutting versus high-pressure balloon angioplasty for treatment of de novo venous stenoses in hemodialysis arteriovenous fistulae. J Vasc Interv Radiol 2015; 10.1016/j.jvir.2015.08.024

2. Aftab SA, Tay KH, Irani FG, et al. Randomized clinical trial of cutting balloon angioplasty versus high-pressure balloon angioplasty in hemodialysis arteriovenous fistula stenoses resistant to high-pressure balloon angioplasty. J Vasc Interv Radiol 2014; 25:190–198.

Post Author:
Luke R. Wilkins, MD

Thrombus Load May Predict Worse Outcome after EVAR

New research in the current issue of JVIR evaluated the impact of two- and three-dimensional preoperative morphologic assessment on CTA on midterm outcomes in patients with AAA treated with EVAR. Sirignano et al., retrospectively evaluated morphologic features of AAA including maximum aortic diameter, thrombus area, overall aneurysm volume, and intrasac thrombus volume (1). This was compared with all perioperative and midterm AAA-related re-intervention and all-cause mortality. Investigators reviewed 191 pre-op CTAs with mean maximum aortic diameter of 58 mm; thrombus area, 49.6%; aortic volume, 159.36 cm3; and thrombus volume, 58.6%. There were no reported cases of re-intervention or mortality in the perioperative period. Mean follow-up was 32 months +/- 16.8 months (range, 3-66 months) with a mortality rate of 9.4%. AAA-related death was 0 and re-intervention rate was a low 8.9%. Causes of re-intervention included type I endoleak (n=3 [1.6%]), type II endoleak (n=7 [3.7%]), type III endoleak (n=1 [0.5%]), endograft limb thrombosis (n=4 [2.1%]), and access vessel thrombosis (n=2; 1%). Predictors for re-intervention included greater thrombus area (>60%) and thrombus volume (>59%). While greater maximum aortic diameter (>59 mm) and aortic volume (>159 cm3) trended to higher reintervention rate, the results were not statistically significant (P=.62 and P =.12). Aortic volume was a predictor of any adverse event, re-intervention, and all-cause mortality after EVAR (P=.03). The authors concluded that thrombus area and volume are risk factors for higher rates of re-intervention and do not represent a protective factor.

Commentary:

The above article is noteworthy as it challenges a commonly held assumption regarding sac thrombus and re-intervention rates. While previous work (2, 3) has suggested that thrombus load is actually protective of future interventions (namely type II endoleak), the current manuscript has shown that this assumption may not be valid. However, the current study has a smaller sample size and a lower rate of re-intervention (8.9% vs 15.4%) when compared with prior work. Further, earlier research focused more on presence or absence of endoleak rather than growth or shrinkage of sac size. Additionally, given changes in device design, one may argue how comparable two sample cohorts from >10yrs apart are. Lastly, given the large number of variables present (neck angulation, neck length, presence or absence of patent vessels within the sac, etc.) it may be difficult to tease out meaningful conclusions from a small data set. Regardless, if nothing else, the questions raised in the manuscript point to the continued need for research in this challenging patient population.

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1. Sirignano, et al. Preoperative intrasac thrombus load predicts worse outcome after elective endovascular repair of abdominal aortic aneurysms. J Vasc Interv Radiol 2015; 26:1431-6. 

2. Rai D, Wisniowski B, Bradshaw B, et al. Abdominal aortic aneurysm calcification and thrombus volume are not associated with outcome following endovascular abdominal aortic aneurysm repair. Eur Radiol 2014; 24:1768–1776. 28. 

3. Sampaio SM, Panneton JM, Mozes GI, et al. Aneurysm sac thrombus load predicts type II endoleaks after endovascular aneurysm repair. Ann Vasc Surg 2005; 19:302–309.


Post Author:
Luke R. Wilkins, MD

Fixing Visceral Pseudoaneurysms with N-Butyl Cyanoacrylate Glue

Recent research from Madhusudhan, et al. has demonstrated that conventional wisdom may not always apply to every visceral aneurysm undergoing endovascular repair. In an upcoming article from JVIR, the group reports their retrospective review of 31 patients with visceral PSAs treated with NBCA. Common indications for using glue included preservation of a major feeding artery, difficult catheterization secondary to arterial tortuosity, failed coil embolization, and short landing zone for coils. The mean amount of glue used was a surprisingly petite 0.24 mL (range, 0.1-1.1 mL). Immediate technical success was seen in all patients with recurrence in 3 (9.7%) and overall clinical success in 90.3%. Major complications were seen in 3 patients (9.7%) and included nontarget embolizations to liver and spleen as well as catheter adhesion and fracture. The authors used a modified technique for glue injection with no more than 0.3 mL (3:7 ratio of NBCA to lipiodol) injected at one time. The aliquots of glue were flushed from the deadspace of the catheter with 50% dextrose until it opacified the PSA. The sequence was then repeated until embolization was complete. The authors concluded that NBCA is a safe and effective embolization agent for treatment of PSA.

Commentary:

The endovascular repair of visceral pseudoaneurysms encompasses a heterogenous set of technical challenges that have been well described using conventional techniques of coil embolization. In the majority of cases, classic coil embolization to exclude the PSA is both technically achievable and well tolerated. However, in a minority of cases, this approach may not be possible secondary to anatomic challenges. Alternative techniques to overcome these challenges include covered stent placement and stent-assisted coil embolization. With NBCA, the interventionalist has yet another tool to overcome these often challenging cases. The authors’ description and figures highlighting potential complications associated with use of NBCA for PSA repair highlight the need for the operator to be familiar and experienced in the use of this embolization agent prior to its use in these challenging circumstances.

Figure 2. Preservation of major feeding artery. A 40-year-old woman presented with acute gastrointestinal bleeding after cholecystectomy. (a) DSA image showing PSA (arrow) arising from the right posterior hepatic artery. (b) Image obtained after embolization showing NBCA cast in the PSA (arrow) with microcatheter in situ. (c) Image obtained after embolization showing preserved divisions of the right hepatic artery (white arrows) with nonopacification of the PSA (black arrow). Use of a microcoil in this case would have occluded the right posterior hepatic artery with risk of hepatic ischemia/infarct. Use of NBCA preserved the artery.

Figure 6. Complications. (a) Reflux of NBCA into the branches of the right hepatic artery (arrows) during embolization of cystic artery PSA (arrowhead). (b) Reflux of NBCA into branches of the splenic artery (arrow) during embolization of splenic artery PSA (arrowhead). (c) Microcatheter fracture in the splenic artery (white arrows) with NBCA cast (black arrows).

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Madhusudhan KS, et al. Endovascular embolization of visceral artery pseudoaneurysms using a modified injection technique with N-Butyl cyanoacrylate glue. Journal of Vascular and Interventional Radiology 2015. DOI: 10.1016/j.jvir.2015.07.008

Post Author:
Luke R. Wilkins, MD

New Data Supports Use of Vascular Plug-Assisted Retrograde Transvenous Obliteration (PARTO) for the Treatment of Gastric Varices and Hepatic Encephalopathy

A new prospective, multicenter study from investigators in Korea supports the use of PARTO in the treatment of GVs and HE. 73 consecutive patients were included from two institutions. 57 of the 73 patients had GVs with 28 in danger of rupture, 23 with recent bleeding, and 6 with active bleeding. 16 of the 73 were done for HE recalcitrant to medical therapy. The study reported a 100% technical success rate with no procedure-related complications. A 1 week follow-up CT was obtained and showed complete thrombosis in 72 of 73 patients (98.6%). 60 patients had follow-up to at least 3 months and all 60 showed complete obliteration. Of this group of 60 patients, there was no development of rebleeding or HE at end of follow-up. The authors concluded that PARTO can be “rapidly performed with high technical success and durable clinical efficacy for the treatment of GVs and HE in the presence of a portosystemic shunt.”

Comment:

This is the first, prospective multicenter trial evaluating PARTO in the treatment of GVs and HE in patients with a portosystemic shunt. Previous work by Gwon et al. discussed the use of PARTO in a limited number of patients and in a retrospective fashion. While BRTO has been considered a first-line treatment in the appropriate patients, the present manuscript makes a strong argument to consider PARTO in more patients. Clear advantages include logistical issues related to prolonged balloon inflation as well as the relative safety of PARTO when compared with BRTO. However, there are anatomical and clinical considerations that should be made. There are instances when it is not anatomically feasible to get an appropriately sized sheath into the shunt deep enough to deploy the Amplatzer. Further, while the data of the present study indicate that the nidus of the varix was appropriately embolized, it would seem intuitive that the foam sclerosant of BRTO would more effectively and efficiently treat the varix when compared with a gelfoam slurry given its ability to travel into smaller vessels in a more effective manner. Lastly, the patient population presented in the current manuscript is likely different than the population treated in North America and Europe and this will likely impact results as well. Regardless, the results are compelling and warrant careful consideration and further research.




Images from a 55-year-old man with GVs. (a) Contrast-enhanced CT obtained before PARTO shows GVs (asterisk). Note the hypertrophied left gastric vein (arrowhead). (b) After placement of the vascular plug (white arrow) within the narrowest portion of the portosystemic shunt via the left adrenal vein, additional embolization of the gastrorenal shunt, GVs (asterisk), and left gastric vein (arrowhead) was performed by using gelatin sponge particles through the 4-F catheter (black arrow). (c) Contrast-enhanced CT scan obtained 3 months after PARTO shows complete obliteration of the GVs.

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Gwon, et al. Vascular Plug–Assisted Retrograde Transvenous Obliteration for the Treatment of Gastric Varices and Hepatic Encephalopathy: A Prospective Multicenter Study. Journal of Vascular and Interventional Radiology 2015. DOI: 10.1016/j.jvir.2015.07.011

Post Author:
Luke R. Wilkins, MD

New Research Explores the Tumor Microenvironment Post-Embolization

Recent research from investigators at the NIH (1) has attempted to quantify changes in the tumor microvascular (<1 mm) perfusion as compared to normal, standard angiographic endpoints. As per usual, this manuscript accurately portrays how little we know about what chemoembolization actually does on the microscopic level. Johnson et al. used a rabbit Vx2 liver tumor and embolized with 100-300-µm LC Bead particles to endpoints of substasis or complete stasis. A novel method of evaluation was used to define microvascular perfusion by delivering two different fluorophore-conjugated perfusion markers through the catheter before embolization and 5 min after reaching the desired angiographic endpoint. Tumor microvasculature was then labeled with an anti-CD31 antibody and analyzed with fluoroscene microscopy for perfusion marker overlap/mismatch. Embolization to substasis eliminated perfusion in 37% +/-9 of perfused microvessels while embolization to stasis eliminated perfusion in 56%+/- 8 of perfused microvessels. Further, embolization to substasis resulted in 8% newly perfused microvasculature. This amount is not statistically significant from control (12%) and likely reflects intermittent fluctuations in perfusion often found in solid tumors. Embolization to stasis resulted in <1% newly perfused microvasculature. The authors concluded that these findings suggest that angiography is not capable of detecting residual tumor microvascular perfusion. Further, while embolization to both substasis and stasis permitted persistent microvascular perfusion, embolization to stasis eliminated newly perfused microvasculature and this may significantly impact tumor microenvironment.

Comment:

While this research may not have immediate implications on your current practice, it is a valuable manuscript for identifying the fallacies of both the intervention we perform and the method we use to monitor that treatment. The research community has long attempted to explore and define the tumor microenvironment and the effect of embolization. Even from the work by Yumoto et al. (2) in 1985 on detecting HCC by iodized oil we have attempted to understand the therapy delivered and its effect on the microvasculature. However, our knowledge on this topic remains woefully incomplete. The current manuscript is noteworthy because it attempts to define what happens to the microvasculature with LC Bead embolization. More specifically, this manuscript demonstrated the dynamic changes that occur in tumor microvascular perfusion following embolization. While there are limitations in the present study, the authors developed a novel method for quantification that yielded interesting results and will hopefully spur additional research on the topic leading to better and more effective therapy.



Microvascular perfusion analysis with embolization to angiographic stasis. Representative perfusion maps generated from MATLAB processed data (CD31+ microvessels and lectin perfusion markers;  from a Vx2 tumor illustrate localization of the microvasculature. The perfusion map legend indicates the color that represents the perfusion status of the microvasculature after substasis embolization. The box in the perfusion map of the entire tumor cross section indicates the region of magnification for the perfusion map zoom.

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1. Johnson GC, et al. Microvascular perfusion changes following transarterial hepatic tumor embolization. Journal of Vascular and Interventional Radiology 2015. DOI: 10.1016/j.jvir.2015.06.036

2. Yumoto, Y., et al. Hepatocellular carcinoma detected by iodized oil. Radiology 1985;154:19-24.

Post Author:
Luke R. Wilkins, MD

Coverage of left subclavian artery during TEVAR may require a more liberal strategy to prevent endoleaks

A recent study from researchers at the University of Virginia was done to report the outcomes of coverage of the LSCA during TEVAR. A retrospective review was performed and included 285 patients with 98 (34%) having coverage of the LSCA. Of the covered patients, the LSCA was revascularized at time of initial TEVAR in 44/98 (45%). Of the remaining 54 patients, 10 (19%) required subsequent revascularization for claudication. LSCA embolization was performed in 33/98 patients at time of LSCA coverage. However, 8 of remaining 65 patients required subsequent embolization for persistent endoleak. There was a statistically significant increased CVA rate with coverage of the LSCA when compared with uncovered (11% vs 3%). While the authors concluded that a selective LSCA revascularization and embolization strategy is well tolerated, a more liberal strategy may be required to decrease rates of delayed revascularization and embolization procedures.

Comment:

The study used a previously established selective revascularization strategy based on a set of indications identifying patients at higher risk of CVA and spinal cord ischemia. While this selective LSCA revascularization and embolization strategy is well tolerated with acceptable rates of CVA and spinal cord ischemia, the increased rates of delayed revascularization secondary to arm claudication symptoms and embolization for endoleak suggest that the criteria for and approach to LSCA coverage should be refined. Going forward, given the relatively small sample size of the current study and the heterogenous patient population, it is difficult to make more definitive treatment recommendations regarding revascularization and embolization strategy on the basis of the available data. However, given that many endoleaks were not angiographically evident at time of initial coverage, one may advocate for a more aggressive embolization strategy to prevent the need for future endoleak repair.


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Citation: Contrella BN, Sabri SS, Tracci MC, Stone JR, Kern JA, Upchurch GR, Matsumoto AH, Angle JF. Outcomes of coverage of the left subclavian artery during endovascular repair of the thoracic aorta. Journal of Vascular and Interventional Radiology (2015). DOI: 10.1016/j.jvir.2015.07.022

Post Author:
Luke R. Wilkins, MD

Meta-Analysis Offers Convincing Evidence for use of RFA in Treatment of Unresectable Intrahepatic Cholangiocarcinoma

While surgery with negative resection margins is known to be the only curative treatment option for intrahepatic cholangiocarcinom, most patients are not candidates for curative resection because of advanced stage at the time of initial presentation. Increasingly, radiofrequency ablation has been used in the treatment of hepatic tumors. However, a relatively small amount of research has been performed on this treatment method in this patient population.

The purpose of this study was to perform a meta-analysis and systematic review of the clinical efficacy and safety of radiofrequency ablation in the treatment of intrahepatic cholangiocarcinoma. Authors collected data from Ovid MEDLINE and EMBASE database. Seven out of 144 articles comprising 84 total patients were selected based on strict exclusion criteria. Technical success rate for radiofrequency ablation ranges from 66-100 % with different approaches like ultrasound guided with conscious sedation or intraoperative with general anesthesia. The pooled 1-year, 3-year, and 5-year survival rates were 82% (95% CI, 72%–90%), 47%(95% CI, 28%–65%), and 24% (95% CI, 11%–40%) respectively. While the overall median survival is superior when compared with other arterial-based locoregional therapies, comparison is difficult given a significantly decreased incidence of extrahepatic disease in the present analysis.

Comment:

The present study offers positive data that RFA may be offered in patients with intrahepatic cholangiocarcinoma. While to the interventionalist, it may seem self-evident that RFA would aid in local tumor control in this patient population, this article will aid in the multi-disciplinary setting to demonstrate efficacy and increased use in this difficult patient population. With additional research into ideal ablative technology and factors predictive of recurrence (location, size, grade, etc.) this procedure will become increasingly utilized in the future.


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Citation: Han, K. et al. Radiofrequency Ablation in the Treatment of Unresectable Intrahepatic Cholangiocarcinoma: Systematic Review and Meta-Analysis. Journal of Vascular and Interventional Radiology 26, 943–948 (2015).


Author: Ali Rahmat, MD. Yale University Radiology Resident.

Watershed hepatocellular carcinomas show lower rate of complete response to chemoembolization

"Watershed" hepatocellular carcinomas cross traditional Couinaud hepatic segment boundaries and can be challenging to treat with chemoembolization because they recruit arterial blood supply from multiple segments which can often be difficult to identify. The purpose of this single institution retrospective study was to evaluate complete response rates in watershed and nonwatershed HCCs following a single chemoembolization. One hundred fifty five treatment-naive patients with unresectable HCC that met Milan criteria (83 watershed lesions, 72 non watershed) were treated with superselective chemoembolization (conventional chemoembolization with doxorubicin/cisplatin or drug-eluting embolic agent with doxorubicin). DSA and cone-beam CT were used to identify arterial supply to the tumor prior to treatment. Eight to 12 weeks post embolization, patients were evaluated with cross-sectional imaging and treatment response was assessed using modified RECIST criteria. Complete response after single treatment with chemoembolization was seen in 55.4% of patients with watershed tumors and 72.2% patients with nonwatershed tumors. Watershed tumors with identifiable dual blood supply on cone beam CT showed a trend toward improved complete response rate (61% vs 53%). Disease free survival was longer in the nonwatershed group (336 days) compared to the watershed group (151 days).

Comment: 

Similar to prior studies, watershed tumors in this series were at higher risk of incomplete response following chemoembolization compared to HCCs within a single hepatic segment. In addition, this study suggests the use of cone-beam CT can be helpful to assess dual blood supply of watershed tumors. The interesting data presented suggest that patients with watershed patients should be monitored and treated more aggressively in order to bridge these patients to transplant.


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Images from a 63-year-old man with cirrhosis secondary to hepatitis C and a 2.2-cm HCC in segment IVa/VIII. (a, b) Contrast- enhanced cone-beam CT images demonstrate tumoral supply from segment IV (thick arrow, a), segment VIII (thin arrow, a), and segment III (arrowhead, b) arteries. (c, d) Selective catheterization and delivery of the chemoembolic emulsion was performed via segment IV (c, arrow), segment VIII (d, arrow), and segment III (not shown). Circumferential uptake of the chemoembolic emulsion was confirmed on digital imaging during selective catheterization and by an unenhanced cone-beam CT acquisition at completion (e). (f) Contrast-enhanced, multiphasic MR image obtained at 6 weeks following chemoembolization demonstrates enhancement of the previously treated tumor.


Citation: Kothary, N. et al. Watershed Hepatocellular Carcinomas: The Risk of Incomplete Response following Transhepatic Arterial Chemoembolization. Journal of Vascular and Interventional Radiology 26, 1122–1129 (2015).


Post author: Menaka Nadar, MD. VIR Pathway Resident at University of Virginia

TIPS shows Improved Oxygenation in patients with Hepatopulmonary Syndrome

Hepatopulmonary Syndrome (HPS) results in the deterioration of arterial oxygenation in the setting of liver disease, which is associated with the formation of intrapulmonary vascular dilations (IPVD). The exact cause of such IPVDs is not known but may be related to an increase in vasodilators such as nitric oxide. IPVDs subsequently result in increased ventilation-perfusion mismatch, increased alveolar-arterial gradient (PA-aO2), and decreased partial arterial O2 pressure (PaO2). The only current recognized treatment for HPS is liver transplantation (LT). The authors conducted a MEDLINE literature search which detected patients 18 years or older with HPS undergoing transjugular intrahepatic portosystemic shunt (TIPS) formation for any indication from January 1990 to April 2015. The study identified 12 patients, 10 of which had either very severe or severe HPS, and all of which underwent successful TIPS placement and were followed for an average of 9.3 months. Of the 12 patients, 9 patients had improvements in oxygenation while the remaining 3 did not significantly change. After 4 months, 2 of the 9 patients with initial improvements reverted back to levels before TIPS, and 1 of the 3 patients without a change in oxygenation eventually worsened. Five of the 12 patients identified in the literature review underwent MAA shunt fraction evaluation, and 4 of which demonstrated improvements with decreased shunt fractions following TIPS. The authors conclude that the results of this literature search warrant further evaluation of TIPS in the management of HPS.

Comment: 

Although the authors do acknowledge the limitations of this literature search, namely the small sample size and short follow up duration, the positive initial improvements in arterial oxygenation after TIPS in 9 of the 12 HPS patients identified certainly is encouraging. Additionally the authors underline the lack of complications reported in the series of patients, which is notable given that most of the patients had very severe HPS, which disputes the conceivable conclusion that these patients would be more susceptible to intra-procedural complications. After more investigation, TIPS may play a much larger role in the management of HPS.


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Citation: Tsauo, J. et al. Role of Transjugular Intrahepatic Portosystemic Shunts in the Management of Hepatopulmonary Syndrome: A Systemic Literature Review. Journal of Vascular and Interventional Radiology (2015). doi:10.1016/j.jvir.2015.04.017


Post Author: Brian Gardner, MD VIR Pathway Resident at University of Virginia

No significant increase in hematoma rates for small and large caliber arterial access closure, using the 8-F Angio-Seal Device

Many arterial endovascular interventions now require greater than 8-F access, but the options for approved endovascular closure are limited to suture-mediated devices. This retrospective study was performed to evaluate access complications when using the 8-F Angio-Seal device in closing ≤ 8-F arteriotomies compared to 9-F to 12-F arteriotomies.

137 consecutive patients were identified retrospectively, all who received the 8-F Angio-Seal Device. 76 patients had < 8-F accesses closed (mean sheath size 7.2-F), and 61 patients had 9-F to 12-F accesses closed (mean sheath size 9.7-F). Complication rate for all closures was 8%, with no statistically increased risk with closure of the larger accesses. Note is made, that of the 6 access complications seen with 9-F to 12-F access, none required intervention beyond manual compression (45 minutes ± 15), a Type 1 complication. Two of the five complications for 8-F or less group required intervention (Type 2 complication).

Comment: 

This study was well-designed and demonstrates the safety of use of the 8-F Angio-Seal device for 9-F to 12-F arteriotomies when compared to < 8-F arteriotomies. However, this study was limited by its somewhat small sample size and retrospective nature and this remains an off-label use of the device. While, there are other proven safe endovascular closure devices for accesses larger than 8-F, consideration should be given to the use of this device in access sites >8-F.


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Citation: Baumann, F. et al. Single-Center Experience Comparing the Application of Small-Caliber versus Large-Caliber Arterial Access Closure in a Consecutive Series of Patients. Journal of Vascular and Interventional Radiology (2015). doi:10.1016/j.jvir.2015.04.024


Post Author: Daniel Sheeran, MD. VIR Pathway Resident at University of Virginia

Stent-Graft placement after angioplasty demonstrates improved patency rates compared to angioplasty alone in cephalic arch stenosis

Cephalic arch stenosis is a common cause of fistula dysfunction that has poor patency rates with traditional angioplasty. Stenting has been suggested to improve patency rates; however, to date this is the first prospective study examining the outcomes of stent graft placement for cephalic arch stenosis. This was a randomized, prospective, single blinded study of 14 patients over a four year period, five of whom had PTA alone, and 9 of whom had PTA with placement of a Viabahn stent. The lesions studied showed greater than 50% stenosis, were treated with angioplasty to achieve less than 30% stenosis, and then if randomized to the stent arm, a Viabahn stent was placed and post dilated. Anatomic success (residual stenosis of less than 30%) and clinical success (at least one normal dialysis session post treatment) were achieved in all patients. The mean patency of angioplasty alone was 100 days (range 56-154 days) versus 300 days (range 201-504) in the angioplasty plus stent group. Circuit patency rates (time from intervention to next access thrombosis or intervention) were 0% at 6 months for PTA alone versus 67% at 6 months with PTA and stent (p<0.01).

Comment:

As compared to angioplasty alone, angioplasty plus stent shows improved patency rates in the setting of cephalic arch stenosis greater than 50%. While this study was limited by a small sample size, with enrollment failing to meet the calculated sample size, the results are compelling. Repeat studies are warranted to confirm the authors’ findings.


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(a) Initial fistulogram demonstrates focal stenosis 4 50% near the junction of the cephalic vein with the axillary vein in a 65- year-old woman with right brachiocephalic fistula who presented with decreased access blood flow. (b) After placement of an 8-mm 60-mm stent graft in this patient, a fistulogram demonstrates preservation of flow in the axillary vein. Arrows mark the end point of the stent graft. (c) In another patient, fistulography 8 months after stent-graft placement demonstrates focal stenosis adjacent to the edge (arrow) of the stent graft.


Citation: Rajan, D. K. & Falk, A. A Randomized Prospective Study Comparing Outcomes of Angioplasty versus VIABAHN Stent-Graft Placement for Cephalic Arch Stenosis in Dysfunctional Hemodialysis Accesses. Journal of Vascular and Interventional Radiology (2015). doi:10.1016/j.jvir.2015.05.001


Post Author: Tim Huber, MD. VIR Pathway Resident at University of Virginia

MRI May Predict Midterm Symptom Recurrence after Uterine Artery Embolization for Adenomyosis

Uterine artery embolization (UAE) for adenomyosis has been shown to result in short term symptom relief but may recur after longer follow-up periods. The purpose of this study was to evaluate the relationship between the post-UAE percentage of necrosis and symptom recurrence at midterm follow-up.

This retrospective study analyzed the percentage of necrosis of uterine adenomyosis on contrast-enhanced MR imaging in 50 women who underwent the procedure for symptomatic adenomyosis. Three dimensional reconstruction software was used to measure the volumes of adenomyosis on the baseline scan and the necrotic volume at the 3 month follow up scan, as defined by non-enhancement on T1-weighted post contrast images. Adenomyosis-related symptoms were assessed using an oral questionnaire at baseline and up to 48 months post-procedure.

During the follow up period, symptom recurrence occurred in 24% (12 of 50) of women. Women with < 34.3% necrosis after UAE had a sevenfold higher risk of symptom recurrence compared with patients with > 34.3% necrosis. Initial uterine volume and the type of adenomyosis (focal or diffuse) did not show significant relationships with recurrence. The study was limited by a small number of patients at a single institution. The distribution of the percentage of necrosis found in the patients was heavily skewed in that 38 out of 50 women had > 34% necrosis.

Comment:

The findings suggest that midterm symptom prognosis after UAE for adenomyosis can be predicted by MR imaging at 3 months post-procedure based on percentage of necrosis. This may have implications for early patient management, aggressive imaging, and appropriate counseling. However, the number of limitations in the study warrant further investigation with larger patient populations and additional MRI analysis of necrotic volumes at later intermediate follow up periods.


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A 40-year-old woman who underwent UAE for symptomatic adenomyosis. (a) Sagittal T2-weighted MR image obtained before UAE shows focal junctional zone thickening of the uterus. (b) Sagittal T2-weighted MR image obtained 3 months after UAE shows decreased size of adenomyosis and the uterus. The volume of adenomyosis was calculated semiautomatically to be 142.580 cm3. (c) Sagittal contrast-enhanced T1-weighted MR image obtained 3 months after UAE shows partial necrotic area without enhancement. The volume of necrosis was calculated semiautomatically to be 65.477 cm3. The percentage of necrosis was 45.9%


Citation: Bae, S. H. et al. Uterine Artery Embolization for Adenomyosis: Percentage of Necrosis Predicts Midterm Clinical Recurrence. Journal of Vascular and Interventional Radiology (2015). doi:10.1016/j.jvir.2015.04.026


Author: Laura Traube, MD, MPH, Fellow in Interventional Radiology, UCLA Medical Center

Occlusion of the Internal Iliac Artery is Associated with Smaller Prostate and Decreased Urinary Tract Symptoms

Embolization of the prostatic arteries is emerging as a viable minimally invasive treatment option for patients with lower urinary tract symptoms (LUTS) due to benign prostatic hyperplasia (BPH). This study aimed to examine the relationship between proximal occlusion or iatrogenic embolization of the internal iliac artery (IIA) with the presence of LUTS and prostate size. The study consisted of two parts, with part one including 99 men in whom 39 had occlusion of the IIA (17 unilateral and 22 bilateral), and 60 with no IIA occlusion. Of the 61 occlusions, 33 were due to atherosclerosis, with the remaining occlusions secondary to coil embolization, stenting, or bypass grafting. Part 2 consisted of a cohort of 18 men who underwent endovascular aneurysm repair (EVAR) in whom coil embolization of the IIA was performed unilaterally. Presence of LUTS, BPH, and treatment with alpha blockers, impotence, and buttock claudication were recorded. Patients with LUTS due to other causes were excluded. Part 1 results showed smaller prostate sizes in men with IIA occlusion (20.7cc versus 27.3cc, p=0.001), with no difference in size between unilateral versus bilateral occlusion. Men without IIA occlusion were more likely to have LUTS (p=0.04, OR = 3.7). The 18 men in part 2 had average prostate volume of 30.4cc with a decrease to 21.5cc after EVAR (p=0.00001). In 9 of these patients, LUTS were present before EVAR, with 5 having LUTS after EVAR, as well as an improvement in LUTS in 4 of the 5. BMI and age were not independent predictors of LUTS due to BPH.

Comment:

The study had a sizable patient cohort and the statistical analysis was rigorously assessed, with a separate assessment of a cohort within the studied population. While the study demonstrated a positive relationship between prostate size and presence of LUTS in a population of men with IIA occlusions, several caveats should be observed. First, the study did not assess objective measure of clinical outcomes in the population studied, including urodynamic studies, the International Prostate Symptom Score (IPSS), and the International Index of Erectile Function (IIEF). These parameters are useful in evaluating any study that evaluates therapies for LUTS due to BPH. Furthermore, the mean prostate size in the population was small, with an average volume of 27.3cc. The generally accepted size criteria for prostatic enlargement is 30cc. Also, only a single medical therapy for LUTS due to BPH was assessed, and multiple other medical therapies are available, which were not captured in the study.


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Three representative case examples. (Top) In the first patient, pelvic arteriography (a) and CT angiography (b) demonstrate patent IIAs. The prostate is enlarged (c). (Middle) In the second patient, only one IIA is patent on arteriography (d); there is unilateral IIA occlusion secondary to calcified plaque (e) seen on CT angiography. The prostate is smaller on CT (f). (Bottom) The final patient has bilateral IIA occlusions on arteriography (g) and CT angiography (h). The prostate is small on CT (i). Black arrows (a, d) and white arrows (b, e, h) demonstrate the internal iliac arteries. White arrows (c, f, i) show the prostate.


Although a positive relationship was demonstrated, the authors do not mean to imply that proximal embolization of the IIA is a viable alternative for prostatic artery embolization. The study serves to demonstrate that prostate size and symptoms due to BPH have a relationship with pelvic blood flow, and helps lay the groundwork on which further trials of prostatic artery embolization will be based.


Citation: Deipolyi, A. R., Al-Ansari, S., Khademhosseini, A. & Oklu, R. Occlusion of the Internal Iliac Artery Is Associated with Smaller Prostate and Decreased Urinary Tract Symptoms. Journal of Vascular and Interventional Radiology (2015). doi:10.1016/j.jvir.2015.04.019


Post author: Andre Uflacker MD, Fellow in Vascular and Interventional Radiology, University of Virginia

Endovascular Laser Ablation (EVLA) for the Treatment of Chronic Venous Insufficiency

Endovascular laser ablation (EVLA) for the treatment of chronic venous insufficiency of the lower extremities can be applied to the perforating veins which connect the superficial and deep venous systems. This retrospective study evaluated outcomes of EVLA using a bare-tip fiber with a 1470 nm laser (with or without additional sclerotherapy or microphlebectomy) of 171 perforating veins in 87 patients with 3 month follow up. Of the 171 perforating veins, 49 had previous GSV disruption on the same extremity, 25 had previous SSV disruption on the same extremity, 88 had previous GSV and SSV disruption on the same extremity, and 9 had patent saphenous veins. On follow up, 94% of perforating veins were occluded at 1 month and 98% were occluded at 3 months. Complete chronic venous insufficiency symptom resolution was found to be 82% and 96% at 1 month and 3 month follow up, respectively. Perforator patency after ablation correlated with higher CEAP scores and the presence of prior GSV/SSV interruption.

Comment:

This study demonstrates impressive success rates following bare tip EVLA of perforating veins, both in terms of perforating vein occlusion and improvement in clinical symptoms. The study results are likely more pertinent to patients with pre-existing saphenous interruption given the small subset of patients within the study without pre-existing saphenous interruption. While the clinical utility of treating perforating veins is uncertain and current recommendations from the American Venous Forum and the Society of Vascular Surgery argue for ablation only in close proximity to venous stasis ulcers or advanced disease, this study makes a case for revisiting these recommendations. Future studies with follow up extended past 3 months would be notable to determine long term efficacy of perforator ablation.


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Color US images demonstrate a dilated perforating vein in the region of the right medial calf with spontaneous bidirectional flow.


Citation: Chehab, M. et al. Endovenous Laser Ablation of Perforating Veins: Feasibility, Safety, and Occlusion Rate Using a 1,470-nm Laser and Bare-Tip Fiber. Journal of Vascular and Interventional Radiology 26, 871–877 (2015).


Post author: Brian Gardner, MD, Resident in the VIR Pathway, University of Virginia

Proximal splenic artery embolization appears to be a safe alternative to distal splenic embolization in the setting of chemotherapy induced thrombocytopenia

Chemotherapy induced thrombocytopenia results in suboptimal cancer treatment due to interruption of chemotherapy and reduced dosing, as well as complications secondary to bleeding and transfusion. Distal splenic artery embolization is an alternative to medical therapy for CIT; however, there is a high rate of post-embolization syndrome associated with the procedure. In this retrospective study, 13 patients underwent proximal splenic artery embolization for CIT. Embolization of the splenic artery was performed distal to the origin of the dorsal pancreatic and pancreatica manga arteries with platinum coils oversized by 2-3 mm. The mean post procedure peak platelet count was 209x109 /L, increased from an average of 45x109 /L (p<0.01.) All patients were deemed eligible to resume chemotherapy by their oncologists. The splenic infarction rate at follow up was 29.5%. One patient developed symptoms consistent with post-embolization syndrome, and was treated with tramadol and Medrol dose pack. As an alternative to distal splenic embolization, the authors show that PSAE is safe, and allowed the patients studied to resume chemotherapy on average by 22 days post-procedure. Additionally, the splenic infarction rate appears lower than has been reported for DSE, resulting in a lower rate of post-embolization syndrome.

Comment:

Within the limitations of a small sample size, the current study demonstrates that PSAE is a safe alternative to DSE. The mean platelet count increased significantly after treatment, and all of the patients were deemed eligible to resume chemotherapy by their treating oncologists. Further investigation is warranted to compare PSAE and DSE in terms of efficacy and complication rate.


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Images from a 69-year-old man with a history of cholangiocarcinoma who developed CIT while he was being treated with gemcitabine and cisplatin. The platelet count decreased to 32 109/L; chemotherapy was discontinued and the patient was referred for PSAE. Pre-PSAE MR imaging (a) and splenic artery angiography (b) show an enlarged spleen consistent with hypersplenism. (c) DSA demonstrates coil embolization of the main splenic artery. (d) MR imaging at 1-year follow-up shows significant reduction in size of the spleen and a large area of infarct replacing approximately 50% of splenic parenchyma.


Citation: Bhatia, S. S. et al. Proximal Splenic Artery Embolization in Chemotherapy-Induced Thrombocytopenia: A Retrospective Analysis of 13 Patients. Journal of Vascular and Interventional Radiology (2015). doi:10.1016/j.jvir.2015.04.003


Post author: Timothy Huber MD, VIR Pathway Resident, University of Virginia

“Eyeballing” It May Not Be As Reliable As We Tell Ourselves

Thousands of peripheral vascular interventional procedures are performed annually to characterize, prevent, and treat consequences of atherosclerosis leading to arterial stenosis. A simple visual estimation (SVE) of the degree of stenosis is often used to determine if treatment is necessary. This study was performed to evaluate the reliability, accuracy and agreement of SVE compared to manual caliper measurements with regard to stenosis severity. This is a retrospective review of images of iliofemoral and carotid arterial lesions, with caliper measurements of stenotic images obtained prior to SVE evaluation. SVE was performed by 23 interventionists of different subspecialties and varying years of experience and compared to the caliper measurement. Correlation among estimates (reliability) was high for both intrareader and interreader image evaluation. Accuracy of visual estimate within 5% of the caliper measurement was 28.3 % overall, however highest for severe stenosis at 52.8%. Agreement as determined by whether SVE and caliper measurement of an image placed it in the same category of stenosis was 64% overall, and highest for severe stenosis at 92.6%. The findings of this study demonstrate SVE is a reliable but inaccurate method for determining degree of stenosis.

Comment:

The study points out the inaccuracy of SVE, which could lead to misclassification of a lesion resulting in inappropriate course of treatment. However, SVE allows for a reliable assessment of significant stenosis (>50%), highlighting its use as a potential screening tool.


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Note–Entries are counts (n) and percentages (%) of visual estimates within 5% of caliper measurement.


Citation: Rajebi, M. R. et al. Reliability and Accuracy of Simple Visual Estimation in Assessment of Peripheral Arterial Stenosis. Journal of Vascular and Interventional Radiology 26, 890–896 (2015).


Post author: Jamie Doster MD, Radiology Resident, University of Virginia

Covered Stents in Use of Kissing Iliac Lesions

Atherosclerotic occlusive disease involving the aortic bifurcation has historically been treated with surgical bypass; however endovascular treatment with the “kissing” stent technique is now considered a durable alternative treatment option. The aim of this retrospective review was to describe the performance of kissing covered balloon expandable stents (CBES) for aortoiliac occlusive disease at the level of the aortic bifurcation after a follow-up of up to 4 years. During the study time period, 73 kissing CBES procedures were performed, 42 primary procedures and 31 secondary procedures after prior endovascular interventions (excluding 4 patients previously treated with CBES). Primary outcomes were primary patency and freedom from target lesion reintervention (TLR), with loss of primary patency defined as a CBES that occluded, a CBES with restenosis or that required reintervention. Secondary outcomes were secondary patency, clinical improvement, and mortality. 22 TASC A, 21 TASC B, three TASC C and 23 TASC D lesions were treated with the kissing stent technique. Duplex ultrasound follow up examination was available for 51 patients at 1 year, 41 patients at 2 years, and 25 patients at 4 years. Primary patency was 88.1% at 1 year, 78.8% at 2 years and 71.5 % at 4 years, with loss of primary patency primarily occurring due to occlusion in 78% of the cases. Secondary patency rates were 88.1% at 1 year, 82.8% at 2 years and estimated secondary patency was 75.3% at 4 years. Freedom from TLR was 92.4% at 1 year and 76.5% at 4 years. While both primary and secondary patency rates were improved in the primary stent placement group compared to the reintervention group, this was not found to be significant at univariate analysis.

Comment: 

Although retrospective in design and with a limited number of patients available for follow up out to the 4 year time period, the results are comparable to other similar cohort studies and show satisfactory patency rates within 4 years of intervention. Also noteworthy is the improved primary and secondary patency rates demonstrated for primary stent placement compared to secondary stent placement.


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Kaplan-Meier survival curves showing patency rates and target lesion revascularization.


Citation: Grimme, F. A. B., Spithoven, J. H., Zeebregts, C. J., Scharn, D. M. & Reijnen, M. M. P. J. Endovascular Treatment of Occlusive Lesions in the Aortic Bifurcation with Kissing Polytetrafluoroethylene Covered Stents. Journal of Vascular and Interventional Radiology (2015). doi:10.1016/j.jvir.2015.04.007


Post author: Jamie Doster MD, Radiology Resident, University of Virginia