Comparison of pharmacological thrombolysis with mechanical thrombectomy in thrombosed arteriovenous fistulas and grafts: a systemic review and meta-analysis

AIM

To compare the effectiveness and safety of pharmacological thrombolysis and mechanical thrombectomy.

MATERIAL AND METHODS

This review was conducted in accordance with the PRISMA guidelines. Pooled proportions and subgroup analysis were calculated for primary and secondary patency rates, technical success, clinical success, major and minor complications rates.

RESULTS

This systematic review identified a total of 6,492 studies of which 17 studies were included for analysis. A total of 1,089 patients comprising 451 (41.4 %) and 638 (58.6 %) patients who underwent thrombolysis and mechanical thrombectomy procedures, respectively, were analysed. No significant differences were observed between thrombolysis and mechanical thrombectomy procedures in terms of technical success, clinical success, major and minor complications rates, primary and secondary patency rates; however, subgroup analysis of overall arteriovenous fistulas (AVFs) and arteriovenous grafts (AVGs) demonstrated a significantly higher rate of major complications within the AVF group (p=0.0248).

CONCLUSION

The present meta-analysis suggests that pharmacological thrombolysis and mechanical thrombectomy procedures are similarly effective and safe; however, AVFs are subject to higher major complications compared to AVGs.

Transcatheter closure of a coronary artery to pulmonary artery fistula with two sequential giant aneurysms

A 73-year-old female presented with exertional dyspnea and was found to have a coronary artery to pulmonary artery fistula with 2 sequential giant aneurysms. Her chest radiograph showed a mass above the cardiac silhouette.

Study protocol for a Prospective, Randomized controlled trial of stEnt graft and Drug-coated bAlloon Treatment for cephalic arch stenOsis in dysfunctional arteRio-venous fistulas (PREDATOR)

BACKGROUND

Treatment of cephalic arch stenosis (CAS) is associated with high risk of failure and complications. Although stent-graft (SG) placement has improved patency rates, stent edge restenosis has been raised as a potential limiting factor for SG usage in CAS. This study aims to evaluate the safety and efficacy of combining stent graft placement with paclitaxel-coated balloon (PCB) angioplasty versus PCB alone in the treatment of CAS.

METHODS

This is an investigator-initiated, prospective, international, multicenter, open-label, randomized control clinical trial that plans to recruit 80 patients, who require fistuloplasty from dysfunctional arteriovenous fistula (AVF) from CAS. Eligible participants are randomly assigned to receive treatment with SG and PCB or PCB alone in a 1:1 ratio post-angioplasty (n = 40 in each arm). Randomization is stratified by de novo or recurrent lesion, and the participants are followed up for 1 year. The primary endpoints of the study are target lesion primary patency (TLPP) and access circuit primary patency (ACPP) rates at 6-months. The secondary endpoints are TLPP and ACPP at 3- and 12-month; target lesion and access circuit assisted primary and secondary patency rates at 3, 6, and 12-months and the total number of interventions; complication rate; and cost-effectiveness.

DISCUSSION

This study will evaluate the clinical efficacy and safety of combination SG and PCB implantation compared to PCB alone in the treatment of CAS for hemodialysis patients.

Sirolimus-coated balloon angioplasty in maintaining the patency of thrombosed arteriovenous graft: 1-year results of a prospective study

BACKGROUND

A prospective, pilot study was designed to test the feasibility of using sirolimus-coated balloon (SCB) to treat graft vein junction of thrombosed arteriovenous graft (AVG) following successful pharmacomechanical thrombectomy. The present report provides the 1-year results of this study.

METHODS

This is a 1-year follow-up of a single, prospective, single-arm study that was conducted from 2018 to 2019 in 20 patients who presented to a tertiary institution with thrombosed AVG. The recruited patients received SCB angioplasty at the graft-vein junction following successful endovascular thrombectomy of a thrombosed AVG. One year after recruitment, there were three deaths, one AVG revision, and one AVG explantation among the participants recruited. The outcomes of 15 subjects at 1-year following the index procedure obtained from electronic medical records were re-examined.

RESULTS

The 1-year access circuit primary patency rate was 40%, while assisted primary and secondary patency rates were 46.7% and 73.3%, respectively. A total of 16 interventions (4 angioplasties, 12 thrombectomies) were performed in 9 patients over the 12 months. Four AVGs were abandoned. The median number of interventions per patient was 1 (0-3) per year. Using Kaplan-Meier analysis, the mean estimated post-intervention access circuit primary patency was 230 (95% CI: 162-300) days, while access circuit assisted primary patency was 253 (95% CI: 187-320) days, and access circuit secondary patency was 292 (95% CI: 230-356) days. Sub-group analysis did not show a significant difference in the mean estimated primary patency between AVG with de novo and recurrent stenosis (245 days, 95% CI: 151-339 vs 210 days, 95% CI: 113-307; p = 0.29).

CONCLUSIONS

SCB may help sustain the patency of thrombosed AVG following successful thrombectomy.

Efficacy and safety of low dose, weight-based subcutaneous enoxaparin protocol in recurrent arteriovenous access thrombosis

BACKGROUND

This study aims to evaluate the safety and efficacy of a short-term, low dose, weight-based subcutaneous enoxaparin protocol (SEP) in maintaining the patency of arteriovenous (AV) access with recurrent thrombosis.

METHODS

Prospective follow-up of 25 patients who presented to a tertiary institution with recurrent AV access thrombosis and treated with anticoagulation according to SEP following successful thrombectomy. Patency and safety outcomes of SEP were studied.

RESULTS

The participants were 66.4 ± 10.2 years old and predominantly male (60%) and of Chinese ethnicity (72%). The AV accesses had a median age of 1.4 (0.6, 5.6) years with 60% being non-autogenous arteriovenous access while 40% were autogenous arteriovenous access. Thrombolytic agents (urokinase (72%) or alteplase (28%)) were used in all procedures while adjunct thrombectomy device was used in only four procedures. The mean dose of enoxaparin was 36.0 ± 8.2 mg or 0.64 ± 0.1 mg/kg/day for a mean duration 30.0 days (Interquartile range: 27.5, 31.0). One patient developed minor bleeding episode. Kaplan-Meier analysis demonstrated that the mean thrombosis-free survival pre- versus post-SEP adoption was 27.3 (95% CI 17.9-36.7) versus 183.5 (95% CI 100.1-266.9) days (p < 0.001). After adjusting for the type of thrombolytic agent, use of adjunct thrombectomy device, cutting balloon, drug-coated balloon, and stent graft, SEP remained a significant factor associated with longer thrombosis-free patency (HR 0.166: 95% CI 0.070-0.392, p < 0.001).

DISCUSSION

SEP appears to be a feasible and safe thromboprophylaxis method to improve thrombosis-free patency for AV access with recurrent thrombosis.

The Role of Drug-Coated Balloon in Haemodialysis Arteriovenous Fistula Stenosis Management

Arteriovenous fistula (AVF) stenosis is a common problem leading to dialysis access dysfunction. The conventional balloon (CB) is the most commonly used device during angioplasty but suffers from poor durability of results due to neointimal hyperplasia-mediated recurrence. The drug-coated balloon (DCB) is an adjunct to balloon angioplasty that reduces neointimal hyperplasia, thereby improving post-angioplasty patency. Despite the heterogeneity of DCB clinical trials to date, the evidence suggests that DCBs of different brands are not necessarily equal, and that patient selection, adequate lesion preparation and proper DCB procedural technique are important to realize the benefit of DCB angioplasty.

Intraprocedural, Intra-Arterial CT Foot Perfusion Examination for Assessment of Endovascular Therapy in Patients With Critical Limb Ischemia: A Prospective Pilot Study

BACKGROUND

Current techniques to evaluate computed tomography (CT) foot perfusion in patients with critical limb ischemia use high contrast doses and cannot be used during endovascular procedures. CT perfusion of the foot with intra-arterial contrast injection during endovascular treatment in a hybrid angiography CT suite might solve these problems.

PURPOSE

The main objective of this study was to evaluate whether intra-arterial CT foot perfusion using a hybrid CT angiosystem is feasible during endovascular treatment for critical limb ischemia.

MATERIAL AND METHODS

This prospective pilot study investigated intraprocedural, intra-arterial CT perfusion of the foot using a hybrid CT angiosystem in 12 patients before and after endovascular treatment for critical limb ischemia. Time to peak (TTP) and arterial blood flow were measured before and after treatment and compared using a paired t test.

RESULTS

All 24 CT perfusion maps could be calculated adequately. The contrast volume used for one perfusion CT scan was 4.8 ml. The mean TTP before treatment was 12.8 seconds (standard deviation [SD] 2.8) and the mean TTP posttreatment was 8.4 seconds (SD 1.7), this difference being statistically significant (p=.001). Tendency toward increased blood flow after treatment, 340 ml/min/100 ml (SD 174) vs 514 ml/min/100 ml (SD 366) was noticed (p=.104). The mean effective radiation dose was 0.145 mSv per scan.

CONCLUSION

Computed tomography perfusion of the foot with low contrast dose intra-arterial contrast injection during endovascular treatment in a hybrid angiography CT suite is a feasible technique.

CLINICAL IMPACT

Intra-arterial CT foot perfusion using a hybrid CT-angiography system is a feasible new technique during endovascular therapy for critical limb ischemia to assess the results of the treament. Future research is necessary in defining endpoints of endovascular treatment and establishing its role in limb salvage prognostication.

Common Designs of Custom-Made Fenestrated Arch Devices and Applicability of an Off-the-Shelf Design

OBJECTIVES

To analyze device designs, similarities and overlaps of custom-made fenestrated arch endografts intended for mid/distal arch thoracic endovascular aortic repair.

MATERIALS AND METHODS

A multicenter cross-sectional study analyzing custom-made anonymized graft plans was performed. Graft plans were included from a cohort of mid/distal aortic arch repairs using custom-made fenestrated aortic endografts treated at 8 centers. Grafts targeting >2 arteries were excluded. No patient/clinical data were analyzed. A descriptive analysis was performed followed by an analysis of overlap of the designs to reach a common design in which the greatest number of grafts would overlap.

RESULTS

One hundred thirty-one graft plans were included. All grafts were custom-made grafts from the COOK Medical Fenestrated arch platform. Ninety-four (71.8%) had a scallop-and-single-fenestration design, 33 (25.2%) had a single fenestration and 4 (4.3%) a single scallop. For analysis purposes, these latter 4 grafts were excluded. Two main graft plans (Plans 1 and 2) were proposed after analysis with similar configuration (1 scallop with 30 mm width, 20 mm height, 12:00 position; 1 preloaded fenestration with 8 mm diameter, 26 mm from the top of the graft and 12:00 position; tapered, with a 193 mm length and 32 mm distal diameter) but with 2 different proximal diameters of 38 mm (Plan 1) and 44 mm (Plan 2), reaching an overall feasibility of 85.8% (n=109), being 47.2% (n=60) and 38.6% (n=49) for each design, respectively.

CONCLUSION

The degree of overlap between the studied fenestrated and/or scalloped thoracic endovascular aneurysm repair (TEVAR) graft designs was high. Future studies analyzing these designs in a real-world cohort of patients are needed to further address off-the-shelf feasibility.

CLINICAL IMPACT

In a multicenter study analyzing 127 fenestrated aortic arch endograft plans from 9 aortic centers, we found that the degree of overlap between the studied fenestrated and/or scalloped arch graft designs was high and that 2 proposed graft designs would be theoretically applicable in 85.8% of cases. Future studies analyzing these designs in a real-world cohort of patients are needed to further address off-the-shelf feasibility.

An approach to genetic testing in patients with metastatic castration-resistant prostate cancer in Singapore

Introduction: There has been a rapid evolution in the treatment strategies for metastatic castration-resistant prostate cancer (mCRPC) following the identification of targetable mutations, making genetic testing essential for patient selection. Although several international guidelines recommend genetic testing for patients with mCRPC, there is a lack of locally endorsed clinical practice guidelines in Singapore. Method: A multidisciplinary specialist panel with representation from medical and radiation oncology, urology, pathology, interventional radiology, and medical genetics discussed the challenges associated with patient selection, genetic counselling and sample processing in mCRPC. Results: A clinical model for incorporating genetic testing into routine clinical practice in Singapore was formulated. Tumour testing with an assay that is able to detect both somatic and germline mutations should be utilised. The panel also recommended the “mainstreaming” approach for genetic counselling in which pre-test counselling is conducted by the managing clinician and post-test discussion with a genetic counsellor, to alleviate the bottlenecks at genetic counselling stage in Singapore. The need for training of clinicians to provide pre-test genetic counselling and educating the laboratory personnel for appropriate sample processing that facilitates downstream genetic testing was recognised. Molecular tumour boards and multidisciplinary discussions are recommended to guide therapeutic decisions in mCRPC. The panel also highlighted the issue of reimbursement for genetic testing to reduce patient-borne costs and increase the reach of genetic testing among this patient population. Conclusion: This article aims to provide strategic and implementable recommendations to overcome the challenges in genetic testing for patients with mCRPC in Singapore. Keywords: Clinical model, genetic counselling, genetic testing, homologous recombination repair genes, metastatic castration-resistant prostate cancer

Cost-Effectiveness of Drug-Coated Balloon Angioplasty Compared With Conventional Balloon Angioplasty for Arteriovenous Access Flow Dysfunction

OBJECTIVES

This study aimed to determine the cost-effectiveness of drug-coated balloon (DCB) angioplasty compared with conventional balloon angioplasty (cPTA) in patients with arteriovenous fistulas (AVFs) and arteriovenous grafts (AVGs) dysfunction from a Singapore healthcare perspective.

METHODS

Existing cost-effectiveness studies comparing DCB and cPTA have not incorporated AVF/AVG abandonment costs. This Markov model-based economic evaluation incorporated AVF/AVG creation and maturation costs on top of routine intervention costs to model a hypothetical cohort of 60-year-old AVF/AVG flow dysfunction patients. Effectiveness was measured in quality-adjusted life-years. Cost-effectiveness was assessed using incremental net monetary benefit (NMB) at a Singapore willingness-to-pay threshold of Singapore dollar (S$)87 000. Deterministic and probabilistic sensitivity analyses were performed to examine parameter uncertainty. To test hypotheses regarding cost-effectiveness, intervention counts per patient, cumulative incidence functions of AVF/AVG abandonment, and survival curves of death were compared between DCB and cPTA.

RESULTS

DCB was not cost-effective at 3-year horizon (NMB = -S$1424), but was cost-effective at 1- and 6-year horizons (NMB = S$356 and S$3738, respectively). At 3 years, there was a 34.5% probability of DCB being cost-effective, but at 1- and 6-year horizons there was, respectively, 58.6% and 59.9% probability of DCB being cost-effective. DCB had graphically less AVF/AVG-abandonments, but this was not statistically significant (P = .21). Differences in other parameters were neither graphically nor statistically significant.

CONCLUSIONS

With AVF/AVG abandonment considered, DCB may be weakly cost-effective compared with cPTA in treating AVF/AVG flow dysfunction. AV access creation and maturation costs could have important explanatory value in assessing DCB cost-effectiveness.

Deeper may not be better: relationship between catheter dysfunction and location of the catheter tip in right-sided tunnelled haemodialysis catheters

AIM

To examine the relationship between catheter tip location and catheter dysfunction in the context of tunnelled central venous catheters (CVCs) for haemodialysis.

MATERIALS AND METHODS

This was a retrospective study of 993 haemodialysis patients who underwent insertion of tunnelled CVCs of step-tip design via the right internal jugular vein (IJV). Based on intra-procedural radiographs, the catheter tip was characterised as being in the superior vena cava (SVC), cavo-atrial junction (CAJ), or deep right atrium (DRA). Patients were tracked for 90 days post-procedure for complications resulting in catheter replacement, and these were compared between cohorts. Statistical analysis was performed with Pearson's chi-square and Fisher's exact tests for categorical variables and two-sample t-test and one-way analysis of variance (ANOVA) for continuous variables.

RESULTS

Ninety-five patients (9.6%) experienced catheter dysfunction necessitating replacement within 90 days of insertion. Tip location in SVC was associated with lower occurrence of catheter dysfunction (1.9%) as compared with the CAJ (8%) and DRA (11%; p=0.049). Catheter replacement due to other complications (catheter-associated bacteraemia, cuff dislodgement, exit-site infection, external catheter damage) showed no statistically significant relation to location of the CVC tip.

CONCLUSION

When utilising tunnelled CVCs with a step-tip design inserted via the right IJV, location of the catheter tip in the SVC is associated with reduced occurrence of catheter dysfunction as compared to either the CAJ or DRA.

The Role of Catheter-Directed CT-Angiography in Radioembolisation

Radioembolisation is an established transarterial therapy for hepatocellular carcinoma and liver metastasis. Success of radioembolisation depends on meticulous angiography and accurate dosimetry. Intra-procedure catheter-directed CT-angiography is commonly performed to improve the efficacy and safety of radioembolisation. This review article will (1) introduce the differences between cone beam CT and hybrid angiography-CT, and (2) describe the benefits of catheter-directed CT-angiography in radioembolisation from both an interventional radiology and nuclear medicine perspective.

Cost-Effectiveness of Drug-Coated Balloon Angioplasty Versus Conventional Balloon Angioplasty for Treating Below-the-Knee Arteries in Chronic Limb-Threatening Ischemia: The SINGA-PACLI Trial

PURPOSE

Drug-coated balloon angioplasty (DCBA) has been studied as a potentially superior option compared to conventional percutaneous transluminal angioplasty (PTA) in treating below-the-knee (BTK) arteries in chronic limb-threatening ischemia (CLTI). The aim of this study is to examine the cost-effectiveness of DCBA versus PTA in BTK arteries based on a randomized controlled trial.

MATERIAL AND METHODS

A prospective economic study was embedded in a randomized controlled trial of 138 patients with CLTI. Resource use and health outcomes were assessed at baseline, and at 3, 6 and 12 months post-intervention. Costs were calculated from a societal perspective and health outcomes measured using quality-adjusted life years with probabilistic sensitivity analysis performed to account for subject heterogeneity.

RESULTS

Compared with participants randomized to receive PTA, participants randomized to DCBA gained an average baseline-adjusted quality-adjusted life years (QALYs) of .012 while average total costs were USD$1854 higher; this translates to an incremental cost-effectiveness ratio (ICER) of US$154,500 additional cost per QALY gained. However, the estimate of ICER had substantial variance with only 48% of bootstrap ICERs meeting a benchmark threshold of US$57,705 (the average gross domestic product (GDP) per capita of Singapore).

CONCLUSION

The use of DCBA in BTK arteries in CLTI patients was not cost-effective compared with PTA.

LEVEL OF EVIDENCE

2, Randomized trial.

Treatment of a Delayed Type IIIb Endoleak 20 Years Post EVAR With Inverted Contralateral Limb Custom-Made Device: A Case Report

PURPOSE

Type III endoleak can be difficult to distinguish from Type I endoleak. Depending on the stent graft anatomy, the use of standard bifurcated endografts may not be technically feasible, and patients may have to be subject to an aorto-uni-iliac repair with femoral-femoral bypass or open surgery.

CASE REPORT

We report a case of an 86-year-old male who had a Type IIIb endoleak 20 years post EVAR which was characterized on angiography to be from a hole close to the bifurcation limb origin. The initial Talent (Medtronic, Santa Rosa, California) device had a 50 mm main body common trunk, which was not amenable to treatment with standard devices. He was successfully treated with a custom-made device with an inverted contralateral limb.

CONCLUSIONS

Our case highlights the need for lifelong surveillance post EVAR as endoleak may present decades post initial EVAR. It also demonstrates that many Type III endoleak which were otherwise deemed unsuitable for treatment with standard devices may potentially be treatable with custom-made device (CMD). This solution preserves a percutaneous option in a now older person which avoids surgical bypass. Further studies are required to establish the durability of this treatment and survey for recurrence.

SIroliMus coated angioPlasty versus plain balloon angioplasty in the tREatment of dialySis acceSs dysfunctION (IMPRESSION): study protocol for a randomized controlled trial

Background

Percutaneous transluminal angioplasty is the current standard treatment for arteriovenous fistula (AVF) stenosis. The mid- and long-term patency with plain balloon angioplasty (PBA) is however far from satisfactory. While paclitaxel-coated balloon angioplasty has been shown to be superior to PBA, concern over its safety profile has recently arisen after a reported possible increased mortality risk with a meta-analysis of large lower limb studies. An angioplasty balloon with a new type of drug coating, the sirolimus-coated balloon (SCB), has been proven to improve patency in the coronary arteries. However, its effect on AV access has yet to be studied.

Methods/design

This is an investigator-initiated, prospective, multicenter, double-blinded, randomized controlled clinical trial to assess the effectiveness of SCB compared to PBA in improving the patency of AVF after angioplasty. A total of 170 patients with mature AVF that requires PTA due to AVF dysfunction will be randomly assigned to treatment with a SCB or PBA at a 1:1 ratio, stratified by location of AVF and followed up for up to 1 year. The inclusion criteria include [1] adult patient aged 21 to 85 years who requires balloon angioplasty for dysfunctional arteriovenous fistula [2]; matured AVF, defined as being in use for at least 1 month prior to the angioplasty; and [3] successful angioplasty of the underlying stenosis with PBA, defined as less than 30% residual stenosis on digital subtraction angiography (DSA) and restoration of thrill in the AVF on clinical examination. The exclusion criteria include thrombosed or partially thrombosed access circuit at the time of treatment, presence of symptomatic or angiographically significant central vein stenosis that requires treatment with more than 30% residual stenosis post angioplasty, and existing stent placement within the AVF circuit. The primary endpoint of the study is access circuit primary patency at 6 months. The secondary endpoints are target lesion primary patency; access circuit-assisted primary patency; access circuit secondary patency at 3, 6, and 12 months; target lesion restenosis rate at 6 months; total number of interventions; complication rate; and cost-effectiveness. The trial is supported by Concept Medical.

Discussion

This study will evaluate the clinical efficacy and safety of SCB compared to PBA in the treatment of AVF stenosis in hemodialysis patients.

Trial registration

ClinicalTrials.govNCT04409912. Registered on 1 June 2020

Drug Coated Balloons for Dysfunctional Haemodialysis Venous Access: A Patient Level Meta-Analysis of Randomised Controlled Trials

OBJECTIVE

To perform an individual patient data level meta-analysis of randomised controlled trials comparing drug coated balloon angioplasty (DCB) against conventional percutaneous transluminal angioplasty (PTA) in the treatment of dysfunctional haemodialysis venous access.

METHODS

A search was conducted from inception to 13 November 2020. Kaplan-Meier curves comparing DCB with PTA by target lesion primary patency (TLPP) and access circuit primary patency (ACPP) were graphically reconstructed to retrieve patient level data. One stage meta-analyses with Cox models with random effects shared frailties were conducted to determine hazard ratios (HRs). Dynamic restricted mean survival times (RMST) were conducted in view of violation of the proportional hazards assumption. Conventional two stage meta-analyses and network meta-analyses under random effects Frequentist models were conducted to determine overall and comparative outcomes of paclitaxel concentrations used. Where outliers were consistently detected through outlier and influence analyses, sensitivity analyses excluding those studies were conducted.

RESULTS

Among 10 RCTs (1 207 patients), HRs across all models favoured DCB (one stage shared frailty HR 0.62, 95% CI 0.53 - 0.73, p < .001; two stage random effects HR 0.60, 95% CI 0.42 - 0.86, p = .018, I² = 65%) for TLPP. Evidence of time varying effects (p = .005) was found. TLPP RMST was + 3.54 months (25.0%) longer in DCB treated patients compared with PTA (p = .001) at three years. TLPP at six months, one year, and two years was 75.3% vs. 58.1%, 51.1% vs. 37.1%, and 31.4% vs. 26.0% for DCB and PTA, respectively. The P-Scores within the Frequentist network meta-analysis suggest that higher concentrations of paclitaxel were associated with better TLPP and ACPP. Among six RCTs (854 patients), the one stage model favoured DCB (shared frailty HR 0.72, 95% CI 0.60 - 0.87, p < .001) for ACPP. Conversely, the two stage random effects model demonstrated no significant difference (HR 0.76, 95% CI 0.35 - 1.67, p = .41, I² = 81%). Sensitivity analysis excluding outliers significantly favoured DCB (HR 0.61, 95% CI 0.41 - 0.91, p = .027, I² = 62%).

CONCLUSION

Overall evidence suggests that DCB is favoured over PTA in TLPP and ACPP.

Randomized Controlled Trial Comparing Drug-coated Balloon Angioplasty versus Conventional Balloon Angioplasty for Treating Below-the-Knee Arteries in Critical Limb Ischemia: The SINGA-PACLI Trial

Background There is a paucity of randomized trials demonstrating superior efficacy of drug-coated balloon angioplasty (DCBA) compared with conventional percutaneous transluminal angioplasty (PTA) for below-the-knee arterial disease in patients with -critical limb ischemia. Purpose To compare DCBA versus PTA for below-the-knee lesions in participants with critical limb ischemia through 12 months. Materials and Methods In this prospective, randomized, two-center, double-blind superiority study, participants with critical limb ischemia with rest pain or tissue loss with atherosclerotic disease in the native below-the-knee arteries were randomly assigned (in a one-to-one ratio) to DCBA or PTA after stratification for diabetes and renal failure between November 2013 and October 2017. The primary efficacy end point was angiographic primary patency at 6 months analyzed on an intention-to-treat basis. Secondary end points through 12 months were composed of major adverse events including death and major amputations, wound healing, limb salvage, clinically driven target-lesion revascularization, and amputation-free survival. Primary and binary secondary end points, analyzed by using generalized-linear model and time-to-event analyses, were estimated with Kaplan-Meier survival curves and hazard ratios (Cox regression). Results Seventy participants (mean age, 61 years ± 10 [standard deviation]; 43 men) in the DCBA group and 68 (mean age, 64 years ± 10; 50 men) in the PTA group were evaluated. The percentage of patients with angiographic primary patency at 6 months was 43% (30 of 70) in the DCBA group and 38% (26 of 68) in the PTA group (P = .48). Through 12 months, the percentage of deaths was similar: 21% in the DCBA group and 16% in the PTA group (P = .43). Amputation-free survival rate assessed with Kaplan-Meier curves differed through 12 months: 59% (41 of 70) in the DCBA group compared with 78% (53 of 68) in the PTA group (P = .01). Conclusion In participants with critical limb ischemia, the drug-coated balloon angioplasty group and the conventional percutaneous transluminal angioplasty group had similar primary patency rates at 6 months after treatment of below-the-knee arteries. Amputation-free survival rates through 12 months were higher in the percutaneous transluminal angioplasty group. © RSNA, 2021 Online supplemental material is available for this article.

Distribution of Peripheral Arterial Disease in Patients Undergoing Endovascular Revascularization for Chronic Limb Threatening Ischaemia: Insights from the Vascular Quality Initiative in Singapore

This study aimed to examine the distribution of lower limb atherosclerotic lesions in a multi-ethnic Asian cohort with chronic limb threatening ischemia (CLTI) from Singapore. The Society for Vascular Surgery Vascular Quality Initiative registry database was used to identify 265 CLTI patients who underwent percutaneous angioplasty between June 2019 and December 2019, of whom 171 (64.5%) were male, and the mean age was 67.9±11.0 years. The majority were diabetic (84.5%) and 145 (54.7%) had chronic kidney disease (CKD). The majority of the lower limb atherosclerotic lesions were de novo lesions (598/797, 75.0%), predominantly TransAtlantic Inter-Society Consensus II C/D (451/797, 56.6%), and were moderately to severely calcified (76.3%). The anterior tibial artery and femoral-popliteal artery were the most commonly affected vessels. The mean length of the treated lesions was 14.5±13.7 cm. There was a tendency, albeit insignificant, of multi-level disease in those who were diabetic or had CKD.

Single-Center Prospective Pilot Study of Sirolimus Drug-Coated Balloon Angioplasty in Maintaining the Patency of Thrombosed Arteriovenous Graft

PURPOSE

To investigate the use of a sirolimus drug-coated balloon (DCB) in the management of a thrombosed arteriovenous graft (AVG).

MATERIALS AND METHODS

A single-center prospective pilot study was conducted between October 2018 and October 2019. Twenty patients (age = 67.0 years ± 10; male = 35%; mean time on dialysis = 31 months) with thrombosed upper limb AVG were enrolled. After successful pharmacomechanical thrombectomy and adequate treatment of the graft vein junction, sirolimus DCB angioplasty was performed at the graft vein junction. The patients were followed-up for 6 months, and all adverse events occurring during the study period were recorded.

RESULTS

The primary circuit patency rates at 3 and 6 months were 76% and 65%, respectively, while the assisted-primary circuit patency rates at 3 and 6 months were 82% and 65%, respectively. The 3- and 6-month secondary circuit patency rates were 88% and 76%, respectively. Using Kaplan-Meier analyses, the estimated mean primary, assisted-primary, and secondary patencies were 285 days (95% confidence interval (CI) = 194-376 days), 319 days (95% CI = 221-416 days), and 409 days (95% CI = 333-485 days). No adverse event directly related to sirolimus DCB use was observed.

CONCLUSIONS

The results of this pilot study suggest that the application of sirolimus DCB at the graft vein junction after the successful thrombectomy of AVG may be a feasible option to improve patency outcomes.

"Angioplasty-First" Approach for Limb Salvage in Asian Patients with Critical Limb Ischemia: Outcomes from 3,303 Angioplasties on 2,402 Limbs in a Single Tertiary Hospital

PURPOSE

To review outcomes of patients with critical limb ischemia (CLI) who underwent conventional percutaneous transluminal angioplasty (PTA) as first-line treatment for revascularization.

MATERIALS AND METHODS

Retrospective review of 3,303 angioplasty procedures on 2,402 limbs in 1,968 patients with CLI was conducted. Mean patient age was 68 years ± 11, and 1,057 patients (54%) were male. Diabetes mellitus (DM) was present in 1,736 patients (88%), and end-stage renal disease (ESRD) in 579 (29%). A majority of patients (90%) had tissue loss. Limb salvage rates were generated by Kaplan-Meier plot. Univariate and multivariate Cox regression analysis was conducted to investigate associations between clinical predictors and time-to-event outcome.

RESULTS

Limb salvage rates at 1, 3, 5, and 10 years were 75%, 73%, 72%, and 62%, respectively, and overall survival rates were 79%, 64%, 56%, and 34%, respectively. In multivariable Cox regression analysis with the outcome of major amputation, significant predictors included age < 69 years (P = .032), Malay race (P = .029), DM (P < .001), history of cerebral vascular disease (P = .003), ESRD (P < .001), Rutherford classification (P = .042), repeat intervention (P = .034), and number of straight-line flows (P < .001) and plantar arch integrity (P < .001) on completion angiography. Significant associations with mortality were age < 69 years (P < .001), male sex (P = .030), Malay race (P = .027), history of ischemic heart disease (P < .001), ESRD (P < .001), and repeat intervention (P < .001).

CONCLUSIONS

PTA as first-line revascularization for patients with CLI is safe and effective. Further studies are suggested to validate the outcome predictive model.

Does reducing radiation levels for procedures affect image quality and radiation to proceduralists? A double-blinded randomised study of two protocols

AIM

To evaluate the ultra-lose dose imaging protocol (ULDP), compared to the standard low-dose imaging protocol (LDP), which are used for haemodialysis access, in terms of radiation exposure and image quality.

MATERIAL AND METHODS

This was a single-centre, institutional review board-approved, prospective, double-blinded randomised controlled study to compare radiation exposure and image quality of the ULDP and LDP. Ten proceduralists, two radiographers, and 11 nurses were enrolled. Radiation exposure during 80 procedures (40 angioplasties and 40 thrombolysis) was recorded (direct radiation to patients from protocol report and scattered radiation to participants from the RaySafe i2 real-time dosimetry system). Baseline characteristics of procedure were recorded. Image quality was assessed subjectively using questionnaires based on the five-point Likert scale after each procedure.

RESULTS

Compared with LDP, the use of ULDP was associated with a significantly lower rate of radiation exposure to proceduralists, patients, and scrub nurses (0.506±0.430 versus 0.847±0.965 μSv/s, p=0.044; 0.571±1.284 versus 1.284±1.007 mGy/s, p<0.001; and 0.052±0.071 versus 0.141±0.185 μSv/s, p=0.005, respectively). No significant difference in image quality or duration of procedure was observed (all p values >0.05).

CONCLUSION

Compared with LDP, the use of ULDP was associated with a significantly lower rate of radiation exposure to proceduralists, patients, and scrub nurses without compromising the image quality or duration of procedure.

Reconfiguring the radiology leadership team for crisis management during the COVID-19 pandemic in a large tertiary hospital in Singapore

Abstract

The coronavirus 2019 (COVID-19) outbreak poses a serious public health risk. To date, the disease has affected almost all countries in the world. The enormous scale of the outbreak and the relative lack of knowledge and information regarding a new virus, as well as the unpredictability of events, make it challenging for leadership teams to respond. This paper shares how we have reconfigured our radiology leadership team into a smaller disease outbreak task force (DOTF) to respond and coordinate all related efforts during this ongoing COVID-19 pandemic. The DOTF format is modelled after the military with domain groups looking at manpower, intelligence, operations, and logistics matters on a daily basis so that timely decisions can be made and action plans executed promptly. In managing the DOTF, discipline, flexibility, and teamwork are key principles, and these are built upon a strong foundation of focus on infection prevention and control, and patient and staff safety as well as staff well-being. The DOTF has positioned us well to confront the many challenges to date. We believe it will also help us navigate the complex issues that will arise with future surges in cases and in formulating strategies to manage exit from the present and future lockdowns.

Key Points

• In a pandemic, regular and directed meetings by a smaller leadership core group are required, for prompt decision making and execution of action plans.

• The military format, with domain groups to look at manpower, intelligence, operations, and logistics matters, is useful in managing a pandemic.

• Discipline, flexibility, and teamwork with strong focus on infection prevention and control, and patient and staff safety as well as staff well-being are key principles for leadership teams managing a pandemic.

A practical and adaptive approach to lung cancer screening: a review of international evidence and position on CT lung cancer screening in the Singaporean population by the College of Radiologists Singapore

Lung cancer is the leading cause of cancer-related death around the world, being the top cause of cancer-related deaths among men and the second most common cause of cancer-related deaths among women in Singapore. Currently, no screening programme for lung cancer exists in Singapore. Since there is mounting evidence indicating a different epidemiology of lung cancer in Asian countries, including Singapore, compared to the rest of the world, a unique and adaptive approach must be taken for a screening programme to be successful at reducing mortality while maintaining cost-effectiveness and a favourable risk-benefit ratio. This review article promotes the use of low-dose computed tomography of the chest and explores the radiological challenges and future directions.

Repurposing the power injectable peripherally inserted central catheter as a tunnelled, non-cuffed, centrally inserted central venous catheter in oncological patients for short- to mid-term vascular access: A pilot study

OBJECTIVES

Usual short- to mid-term vascular accesses for oncologic patients include the peripherally inserted central catheter and non-tunnelled centrally inserted central catheters, inserted in the supraclavicular or infraclavicular area. Peripherally inserted central catheters can be restrictive in active patients; supraclavicular non-tunnelled centrally inserted central catheters are not ideal in terms of exit site location and cosmesis, while infraclavicular non-tunnelled centrally inserted central catheters may be associated with puncture-related complications. In this pilot study, we have evaluated the off-label use of peripherally inserted central catheters as a tunnelled supraclavicular centrally inserted central catheter.

METHODS

Ten patients were recruited for this prospective study. A non-cuffed, power injectable peripherally inserted central catheter was inserted via a short subcutaneous tunnel into the internal jugular vein using the peel-away sheath and introducer as a tunneller. Puncture wounds were closed with tissue glue. Patients were followed up for comfort scores, dwell time and complications.

RESULTS

The median dwell time was 94 days (mean of 113 days). One catheter was removed due to systemic fungemia, resulting in an acceptable complication rate of 0.97 per 1000 catheter days.Mean patient-reported comfort scores was 16 (out of 20). Pressurised injections for computer tomography imaging were performed in five patients without complications.

CONCLUSION

Despite limited numbers, this method appears to be safe and well accepted with low complication rates. This modified vascular access is low profile, easily concealed, readily removable and compatible with pressure injector and uses a commonly found catheter in a modified fashion. Larger prospective trials will be needed to ascertain if it can be a standard of care for oncological patients.

Two-year clinical outcomes following lower limb endovascular revascularisation for chronic limb threatening ischaemia at a tertiary Asian vascular centre in Singapore

INTRODUCTION

Percutaneous transluminal angioplasty (PTA) is commonly used to treat patients with chronic limb-threatening ischaemia (CLTI). This study aimed to examine mortality and functional outcomes in a multi-ethnic Asian population from Singapore of CLTI patients who predominantly had diabetes mellitus.

METHODS

CLTI patients who underwent PTA between January 2015 and March 2017 at the Vascular Unit at Singapore General Hospital, Singapore, were studied. Primary outcome measures were 30-day unplanned readmission, two-year major lower extremity amputation (LEA), mortality rates, and ambulation status at one, six and 12 months.

RESULTS

221 procedures were performed on 207 patients, of whom 184 (88.9%) were diabetics. One-, six- and 12-month mortality was 7.7%, 16.4% and 21.7%, respectively. The two-year LEA rate was 30.0%. At six and 12 months, only 96 (46.4%) and 93 (44.9%) patients were ambulant, respectively. Multivariate analysis revealed that preoperative ambulatory status; haemoglobin; Wound Ischaemia and foot Infection (WIfI) score; and end-stage renal failure (ESRF) were independent predictors for one-year ambulatory status. Predictors of mortality at one, six and 12 months were ESRF, preoperative albumin level, impaired functional status and employment status.

CONCLUSION

PTA for CLTI was associated with low one-year mortality and two-year LEA rates but did not significantly improve ambulation status. ESRF and hypoalbuminemia were independent predictors of mortality. ESRF/CKD and WIfI score were independent predictors of loss of ambulation at six months and one year. We need to better risk stratify CLTI patients to decide between initial revascularisation and an immediate LEA policy.

Adapting Lessons From SARS for the COVID-19 Pandemic-Perspectives From Radiology Nursing in Singapore

When severe acute respiratory syndrome (SARS) hit Singapore in 2003, we began to formulate rigorous protocols and reconfigure our facilities to prevent in-hospital transmission. This became the foundation of our practices in COVID-19. However, some adaptations were made to suit the current needs of the department, and technology has been used for communication. This article describes the preparation and response of nursing in the radiology department in Singapore in SARS and coronavirus 2019 (COVID-19) outbreak. Protocols and measures taken during SARS and COVID-19 outbreak are described. Stringent infection control and prevention measures, detailed standard operating protocols for handling SARS and COVID-19 patients coming for radiological examinations and interventions, team segregation, safe distancing, efficient communication, and rigorous staff surveillance are paramount to ensure patient and staff safety. Our SARS experience has shaped our preparations and response toward the COVID-19 pandemic. To date, there have been zero health care worker transmissions in the department. The crisis has also enhanced the cohesiveness among staff because of the camaraderie and shared experience. The response and measures taken by the radiology department in a large acute care teaching hospital could be practiced in other similar health care settings.

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Regular infection control audits should be part of routine nursing care.

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In a pandemic, more stringent infection control protocols and audits are required.

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Team segregation help to prevent shutdown of services if a staff gets infected.

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Online platforms allow rapid communication, and reduce face-to-face discussions.

Preparing IR for COVID-19: The Singapore Experience

This paper describes country-wide special measures undertaken for interventional radiology staff during the current coronavirus disease 2019 (COVID-19) pandemic. Although each interventional radiology service around the world faces unique challenges, the principles outlined in this article will be useful when designing or strengthening individual practices and integrating them within wider hospital and national measures. Moving beyond the current outbreak, these measures will be useful for any future infectious diseases which are likely to arise.

Type 2 Endoleaks: Common and Hard to Eradicate yet Benign?

PURPOSE

The exact significance of type 2 endoleaks (T2ELs) and the indication and efficacy of treatment are widely debated. We report our experience with managing T2ELs in a tertiary Asian centre.

MATERIALS AND METHODS

This was a retrospective study of patients who underwent endovascular abdominal aortic aneurysm repair (EVAR) between February 2006 and December 2016. Patients with T2ELs were identified, and their data were analysed.

RESULTS

A total of 156 patients underwent EVAR, of which 67 (42.9%) developed T2ELs. Seven were lost to follow-up. The remaining 60 patients had a mean follow-up period of 50.3 ± 33.9 months-34 (56.7%) experienced T2ELs early and the rest (43.3%) had late T2ELs. Forty-one patients had isolated T2EL, whilst 19 had concomitant T1EL and/or T3EL. Spontaneous resolution occurred in 25 patients (41.7%). All T2ELs with stable sac size were on continued surveillance. Amongst those with persistent T2ELs associated with sac growth (n = 17), 14 underwent intervention, of which 7 (50%) received > 1 embolisation procedure. A total of 16 transarterial embolisation and 8 translumbar embolisation procedures were performed. Technical success rate was 75%. In the intervention group, 5 (35.7%) had complete and sustained resolution, 7 had persistent/recurrent T2ELs but stable sac size, and 2 had progressive sac expansion. Overall mortality due to sac rupture occurred in 2 patients with concomitant T2EL and T1EL/T3EL.

CONCLUSION

T2ELs are common, albeit mostly benign if occurring in isolation and not in association with sac growth. Achieving complete T2EL resolution with embolisation is difficult even with reinterventions.

LEVEL OF EVIDENCE

Level 2B, retrospective study.

Interventional Radiology Procedures for COVID-19 Patients: How we Do it

With astonishing speed, COVID-19 has become a global pandemic. As it is uncertain when the pandemic will be controlled, it is crucial for procedurists of all stripes to be familiar and confident in performing procedures for COVID-19 patients to prevent intra-hospital infection. In this article, we will detail our approach on how to perform interventional procedures for COVID-19 patients at the bedside in the isolation room and with the patient transferred to the interventional radiology centre. These workflows have been developed in conjunction with multiple other stakeholders within our hospital, drawing from valuable lessons we have learnt from the SARS outbreak of 2003.

Single-centre retrospective review of risk factors for local tumour progression and complications in radiofrequency ablation of 555 hepatic lesions

INTRODUCTION

This study aimed to assess safety, local tumour progression (LTP) and risk factors for LTP after radiofrequency ablation (RFA) of liver tumours in a single centre.

METHODS

All consecutive patients treated with RFA for liver tumours between January 2009 and October 2012 were included. Previously treated lesions that progressed were excluded. Using electronic medical records, the following data was captured: patient demographics, pre-procedural laboratory results, Child-Pugh status, tumour characteristics, development of tumoral seeding, RFA complications and LTP. Possible risk factors for LTP were identified using Cox regression.

RESULTS

In total, 555 liver tumours were treated in 337 patients. 483 (87.0%) hepatocellular carcinomas, 52 (9.4%) colorectal metastases and 20 (3.6%) other tumour types were treated. Mean tumour size was 2.1 ± 1.1 (range 0.4-6.8) cm. Mean follow-up duration was 387 days. 416 (75.0%) lesions had no LTP at the last imaging. 70 (12.6%) patients had minor complications requiring observation, while 7 (1.3%) patients had significant complications requiring prolonged hospitalisation or further interventions. Only one case of tumour seeding was detected. Using multivariate Cox regression, the following factors were statistically significant in predicting LTP: hilar location (relative ratio [RR] 3.988), colorectal metastases (RR 2.075), size (RR 1.290) and younger age (RR 0.982).

CONCLUSION

RFA of liver tumours is safe and effective, with a low significant complication rate of 1.3%. Hilar lesions are most prone to LTP, followed by lesions that were larger in size and colorectal metastases. 75.0% of patients showed no LTP at the last follow-up.

Outcome and Distal Access Patency in Subintimal Arterial Flossing with Antegrade-Retrograde Intervention for Chronic Total Occlusions in Lower Extremity Critical Limb Ischemia

PURPOSE

To report the outcome and distal access patency of the Subintimal Arterial Flossing with Antegrade-Retrograde Intervention (SAFARI) technique for chronic total occlusion (CTO) in critical limb ischemia (CLI).

MATERIALS AND METHODS

From January 2009 to June 2015, 220 SAFARI procedures were performed for 200 limbs in 191 patients (108 males [56.5%]; median age, 70 years old; range, 36 to 97 years old) with CLI (9.4% were Fontaine classification 3; and 90.6% were Fontaine classification 4). Distal access was obtained from the distal superficial femoral artery (n = 6), popliteal artery (n = 49), anterior tibial artery (n = 56), dorsalis pedis (n = 51), peroneal artery (n = 12), posterior tibial artery (n = 45), and lateral plantar artery (n = 1). Distal access hemostasis was obtained with internal balloon tamponade in 71.4% (n = 157). Outcome measurements were technical success, freedom from major amputation and complications. Preprocedural angiograms of clinically driven repeat interventions were reviewed in 73 cases for distal access patency.

RESULTS

Technical success was achieved in 80.5% (n = 177). Reasons for technical failure include inability to obtain distal access (n = 3), cross the occlusion retrogradely (n = 16), re-enter the true lumen (n = 9), and achieve antegrade blood flow after the procedure (n = 15). Freedom from major amputation for technically successful procedures was 84.7%, 82.9%, and 81.9% at 6, 12, and 24 months, respectively. There were 3 cases of distal access bleeding with 1case that required coil embolization. The distal access remained patent in 80.8% of observable cases with repeated endovascular intervention.

CONCLUSIONS

Distal retrograde arterial access (SAFARI) technique is safe and effective in the treatment of CTOs in the context of CLI, after failure of antegrade revascularization.

Spontaneous spinal epidural haematoma following intra-arterial catheter-directed thrombolysis: A case report

A 79-year-old Chinese gentleman presented with unilateral acute lower limb ischaemia and received intra-arterial catheter-directed thrombolysis, initially with good result and reversal of the ischaemia. However, he developed an extensive spontaneous spinal epidural haematoma within hours of the procedure and was left with permanent paraplegia after being deemed unsuitable for decompressive spinal surgery. This report serves as a reminder of the risk of severe complications of catheter-directed thrombolysis by describing this rare but devastating side-effect that occurred even despite early detection from onset of symptoms.

Homemade Candy Plug Using a Zenith Alpha Thoracic Stent-Graft for False Lumen Distal Occlusion in Acute-on-Chronic Type B Aortic Dissection

Purpose: To report a candy-plug technique using a Zenith Alpha stent-graft to occlude the distal false lumen in a patient with a complicated chronic type B aortic dissection. Case Report: A 50-year-old male smoker presented with chest pain due to rapidly growing complicated chronic type B aortic dissection. Computed tomography angiography (CTA) showed the dissection extending from distal to the origin of the left subclavian artery (LSA) down to the left femoral artery. There was fusiform aneurysmal dilatation of the proximal descending aorta measuring up to 5.8 cm in diameter. He underwent left carotid-subclavian artery bypass, thoracic endovascular aortic repair with a Zenith Alpha stent-graft, a left common carotid artery chimney, and embolization of the proximal LSA. Serial CTA showed persistent false lumen flow. A decision was made to occlude the distal large false lumen using the candy-plug technique. A 44×125-mm Zenith Alpha stent-graft was used to prepare the candy plug. A gutter leak and a type Ia endoleak were embolized via a left brachial artery approach. At 2.5 years, imaging showed the candy plug in position, no endoleak, and the thrombosed false lumen in the thoracic aorta reduced in size. Conclusion: The candy-plug technique is useful in facilitating complete occlusion of the false lumen in chronic aortic dissection, which avoids an open procedure and the risk of higher morbidity.

Catheter-directed thrombolysis versus percutaneous mechanical thrombectomy in the management of acute limb ischemia: a single center review

Background

Acute limb ischemia is associated with significant mortality and amputation rate. Early restoration of flow can be obtained by various treatment methods that include catheter-directed thrombolysis (CDT) and percutaneous mechanical thrombectomy (PMT). These treatments have been shown to be effective but associated with various complications. There is lack of data comparing these two treatments. We aim to review our experience in the treatment of acute limb ischemia (ALI) and compare CDT with PMT.

Results

A total of 94 patients [mean age 65 years, 67% male (n = 63)] presented with ALI between 2006 and 2015 and were treated with either CDT or PMT. Outcomes were retrospectively reviewed. Primary outcomes were technical and clinical success; secondary outcomes were amputation rate at 30 days, duration of hospitalization and 30-day mortality. A total of 117 procedures were performed in 94 patients: 27 surgical bypass grafts, 31 previously stented arteries and 59 native vessels. Twenty eight procedures (24%) were performed with PMT, and 89 (76%) procedures were performed with CDT. Higher technical success was achieved in the PMT group (68%, 19/28) compared to the CDT group (47%, 42/89), p = 0.056. Clinical success was similar in both groups (75%, 21/28 in the PMT group and 73%, 65/89) in the CDT group (p = 0.837). There was no statistically significant difference in 30-day mortality between the PMT vs CDT groups (4% vs 8%, p = 0.425). The length of post-procedural hospital stay was shorter in patients with PMT (6.0 vs 12.6 days, p = 0.001). The absence of end-stage renal failure appears to be a predictor for clinical succes (HR 3.3, 95% CI 0.809–13.592).

Conclusion

PMT is associated with higher technical success and significantly shorter length of stay compared to CDT; however, clinical success is similar across both treatment entities. The safety profile is comparable.

SIRveNIB: Selective Internal Radiation Therapy Versus Sorafenib in Asia-Pacific Patients With Hepatocellular Carcinoma

Purpose Selective internal radiation therapy or radioembolization (RE) shows efficacy in unresectable hepatocellular carcinoma (HCC) limited to the liver. This study compared the safety and efficacy of RE and sorafenib in patients with locally advanced HCC. Patients and Methods SIRveNIB (selective internal radiation therapy v sorafenib), an open-label, investigator-initiated, phase III trial, compared yttrium-90 (⁹⁰Y) resin microspheres RE with sorafenib 800 mg/d in patients with locally advanced HCC in a two-tailed study designed for superiority/detriment. Patients were randomly assigned 1:1 and stratified by center and presence of portal vein thrombosis. Primary end point was overall survival (OS). Efficacy analyses were performed in the intention-to-treat population and safety analyses in the treated population. Results A total of 360 patients were randomly assigned (RE, 182; sorafenib, 178) from 11 countries in the Asia-Pacific region. In the RE and sorafenib groups, 28.6% and 9.0%, respectively, failed to receive assigned therapy without significant cross-over to either group. Median OS was 8.8 and 10.0 months with RE and sorafenib, respectively (hazard ratio, 1.1; 95% CI, 0.9 to 1.4; P = .36). A total of 1,468 treatment-emergent adverse events (AEs) were reported (RE, 437; sorafenib, 1,031). Significantly fewer patients in the RE than sorafenib group had grade ≥ 3 AEs (36 of 130 [27.7%]) v 82 of 162 [50.6%]; P < .001). The most common grade ≥ 3 AEs were ascites (five of 130 [3.8%] v four of 162 [2.5%] patients), abdominal pain (three [2.3%] v two [1.2%] patients), anemia (zero v four [2.5%] patients), and radiation hepatitis (two [1.5%] v zero [0%] patients). Fewer patients in the RE group (27 of 130 [20.8%]) than in the sorafenib group (57 of 162 [35.2%]) had serious AEs. Conclusion In patients with locally advanced HCC, OS did not differ significantly between RE and sorafenib. The improved toxicity profile of RE may inform treatment choice in selected patients.

Extrinsic Compression of the Ovation Stent-Graft Following Glue Embolization for Type II Endoleak: An Unusual Complication

PURPOSE

To describe a case of extrinsic compression of the Ovation stent-graft following glue embolization for type II endoleak.

CASE REPORT

A 75-year-old man with a past history of ischemic heart disease and endovascular aneurysm repair with an Ovation stent-graft was admitted for treatment of type II endoleaks from the right L2 and left L4 lumbar arteries with egress via the inferior mesenteric and right L4 lumbar arteries, respectively. Successful embolization was performed via a translumbar sac puncture with a combination of coils and histoacryl glue. On final angiography severe lumen narrowing of the unsupported portion of the Ovation stent-graft was seen owing to extrinsic compression by the glue. This was successfully salvaged with percutaneous transarterial kissing balloon angioplasty.

CONCLUSION

Aortic lumen narrowing caused by extrinsic compression of an Ovation stent-graft following glue embolization of type II endoleak is an unusual and potentially problematic complication.

Diagnosis and Management of Complications from Percutaneous Biliary Tract Interventions

Complications related to percutaneous biliary tract interventions (PBTIs) can range from access site discomfort to life-threatening vascular complications. These complications are relatively uncommon, and most of them are self-limiting. However, major complications for which an increased level of patient care and/or a prolonged hospital stay are required and that may lead to death-albeit rarely-can occur. Some of the most common complications related to PBTI include pain, infection, bile leakage, and catheter blockage. These conditions can be easily recognized by using the patient's clinical history and laboratory examination results. However, the more uncommon complications, such as life-threatening hemobilia, acute pancreatitis, and catheter and stent fractures, may have nonspecific clinical manifestations, and the underlying pathologic condition may be found only when it is being sought specifically. It is important that diagnostic and interventional radiologists be aware of the wide spectrum of PBTI-related complications, as early recognition and treatment may prevent catastrophic situations. In addition, knowledge of the different treatment options is essential for guidance in interventional radiology procedures such as transarterial control of hemobilia, imaging-guided direct percutaneous embolization of pseudoaneurysms, and percutaneous treatment of catheter- and stent-related complications such as fractures. The authors review a wide spectrum of complications associated with PBTI and the percutaneous management of these conditions. They also highlight valuable lessons learned from morbidity and mortality rounds at a high-volume tertiary care center. ^©RSNA, 2017.

Water-Responsive Shape Recovery Induced Buckling in Biodegradable Photo-Cross-Linked Poly(ethylene glycol) (PEG) Hydrogel

The phenomenon of recovering the permanent shape from a severely deformed temporary shape, but only in the presence of the right stimulus, is known as the shape memory effect (SME). Materials with such an interesting effect are known as shape memory materials (SMMs). Typical stimuli to trigger shape recovery include temperature (heating or cooling), chemical (including water/moisture and pH value), and light. As a SMM is able not only to maintain the temporary shape but also to respond to the right stimulus when it is applied, via shape-shifting, a seamless integration of sensing and actuation functions is achieved within one single piece of material. Hydrogels are defined by their ability to absorb a large amount of water (from 10-20% up to thousands of times their dry weight), which results in significant swelling. On the other hand, dry hydrogels indeed belong to polymers, so they exhibit heat- and chemoresponsive SMEs as most polymers do. While heat-responsive SMEs have been spotted in a handful of wet hydrogels, so far, most dry hydrogels evince the heat and water (moisture)-responsive SMEs. Since water is one of the major components in living biological systems, water-responsive SMMs hold great potential for various implantable applications, including wound healing, intravascular devices, soft tissue reconstruction, and controlled drug delivery. This provides motivation to combine water-activated SMEs and swelling in hydrogels together to enhance the performance. In many applications, such as vascular occlusion via minimally invasive surgery for liver cancer treatment, the operation time (for both start and finish) is required to be well controlled. Due to the gradual and slow manner of water absorption for water-activated SMEs and swelling in hydrogels, even a combination of both effects encounters many difficulties to meet the timerequirements in real procedures of vascular occlusion. Recently, we have reported a bioabsorbable radiopaque water-responsive shape memory embolization plug for temporary vascular occlusion. The plug consists of a composite with a poly(dl-lactide-co-glycolide) (PLGA) core (loaded with radiopaque filler) and cross-linked poly(ethylene glycol) (PEG) hydrogel outer layer. The device can be activated by body fluid (or water) after about 2 min of immersion in water. The whole occlusion process is completed within a few dozens of seconds. The underlying mechanism is water-responsive shape recovery induced buckling, which occurs in an expeditious manner within a short time period and does not require complete hydration of the whole hydrogel. In this paper, we experimentally and analytically investigate the water-activated shape recovery induced buckling in this biodegradable PEG hydrogel to understand the fundamentals in precisely controlling the buckling time. The molecular mechanism responsible for the water-induced SME in PEG hydrogel is also elucidated. The original diameter and amount of prestretching are identified as two influential parameters to tailor the buckling time between 1 and 4 min as confirmed by both experiments and simulation. The phenomenon reported here, chemically induced buckling via a combination of the SME and swelling, is generic, and the study reported here should be applicable to other water- and non-water-responsive gels.

Treatment of an Aortic Arch Aneurysm with Scalloped and Fenestrated Thoracic Stent Graft and Left Carotid to Subclavian Artery Bypass

We report a successful treatment of thoracic arch aneurysm using a combination of hybrid approach and a customized stent graft in a frail patient with challenging anatomy and concomitant large retrosternal goiter. The patient is an 82-year-old lady with multiple comorbidities who presented to her general practitioner for anorexia and significant weight loss. She was incidentally found to have a 6.6-cm saccular distal aortic arch aneurysm, a 5.5-cm infrarenal abdominal aortic aneurysm, and a large goiter adjacent to the left common carotid artery (CCA) with retrosternal extension. The arch aneurysm was successfully managed with an open left common carotid to left subclavian bypass followed by thoracic endovascular aneurysm repair (EVAR) with a Cook stent graft customized to the patient's anatomy incorporating a proximal scallop for the brachiocephalic artery and a fenestration for the left CCA, and Amplatzer plug for occlusion of the ostium of the left subclavian artery. There was no endoleak and she was discharged uneventfully. She is planned for staged EVAR of her abdominal aortic aneurysm at a later date. In the presence of difficult arch aneurysm anatomies, the hybrid approach with bespoke stent grafts is a feasible alternative to open aortic arch replacement.