Clinical outcomes of endovascular treatment of TASC-II C and D femoropopliteal lesions with the Viabahn endoprosthesis

Endovascular Treatment of TASC C and D Femoropopliteal Arterial Disease With Heparin-Bonded Covered Stents: The Impact of Distal Run-Off Vessels

INTRODUCTION

In the last 2 decades, several studies in the literature evaluated the possible role of covered stents in the treatment of TransAtlantic Inter-Society Consensus (TASC) C and D femoropopliteal lesions but, despite the encouraging results, the employment of these devices was never included in clinical guidelines. The aim of this study is to evaluate the role of the technical aspects in patients with TASC C or D lesions that were treated with the GORE VIABAHN endoprosthesis and to elaborate a computerized method to objectively estimate the post-stent run-off and predict stent-graft failure.

MATERIALS AND METHODS

In this monocentric retrospective study, we collected the patients who were treated in our department from December 2014 to May 2021. Inclusion criteria comprised: (1) patients who underwent endovascular treatment of a TASC C or D femoropopliteal lesions using one or more heparin-bonded covered stent(s) and (2) clinical follow-up >2 years. Exclusion criteria were clinical follow-up <2 years or missing. An in-house computerized analysis to estimate the post-stent run-off, CEVERO (Computerized Estimation of VEssel Run-Off), was elaborated.

RESULTS

Sixty-six patients were enrolled in the study. Eleven patients had a TASC type C lesion, and 55 patients presented a type D lesion. The median follow-up time was 2.6 years. Twenty-nine patients (43.9%) experienced a major adverse limb event. Primary patency after 6, 12 and 24 months was 74.2%, 60.6%, and 57.6%; primary-assisted patency was 78.8%, 65.2%, and 59.1%. The presence of <2 run-off vessels (p<0.001) was correlated with stent-graft failure. The CEVERO analysis demonstrated an accuracy of 90.0% in predicting stent-graft failure.

CONCLUSIONS

The treatment of TASC C and D femoropopliteal lesions remains technically challenging. Our study supported the hypothesis that run-off is the most critical factor in determining the outcome of the procedure and that concomitant angioplasty of the tibial vessels might improve the patency of the covered stent. The CEVERO analysis could permit a real-time, objective estimation of the distal run-off using conventional angiographic images, and it might be employed as a tool in the intraprocedural decision-making process, but its clinical applicability should be evaluated on external validation cohorts.

CLINICAL IMPACT

The endovascular treatment of TASC C and D femoropopliteal lesions is technically challenging and run-off seems to be the most critical factor in determining the outcome. Concurrent angioplasty of the tibial vessels can create adequate run-off to avoid stent failure. The CEVERO analysis is a computerized estimation of run-off that might be a useful tool in the decision-making process.

Indications for a "Surgery-First" Approach for the Treatment of Lower Extremity Arterial Disease

BACKGROUND

In recent years, there has been a tendency toward an "endovascular-first" approach for the treatment for femoropopliteal arterial disease. The purpose of this study is to determine if there are patients that are better served with an initial femoropopliteal bypass (FPB) rather than an endovascular attempt at revascularization.

METHODS

A retrospective analysis of all patients undergoing FPB between June 2006 - December 2014 was performed. Our primary endpoint was primary graft patency, defined as patent using ultrasound or angiography without secondary intervention. Patients with <1-year follow-up were excluded. Univariate analysis of factors significant for 5-year patency was performed using χ2 tests for binary variables. A binary logistic regression analysis incorporating all factors identified as significant by univariate analysis was used to identify independent risk factors for 5-year patency. Event-free graft survival was evaluated using Kaplan-Meier models.

RESULTS

We identified 241 patients undergoing FPB on 272 limbs. FPB indication was disabling claudication in 95 limbs, chronic limb-threatening ischemia (CLTI) in 148, and popliteal aneurysm in 29. In total, 134 FPB were saphenous vein grafts (SVG), 126 were prosthetic grafts, 8 were arm vein grafts, and 4 were cadaveric/xenografts. There were 97 bypasses with primary patency at 5 or more years of follow-up. Grafts patent at 5 years by Kaplan-Meier analysis were more likely to have been performed for claudication or popliteal aneurysm (63% 5-year patency) as compared with CLTI (38%, P < 0.001). Statistically significant predictors (using log rank test) of patency over time were use of SVG (P = 0.015), surgical indication of claudication or popliteal aneurysm (P < 0.001), Caucasian race (P = 0.019) and no history of COPD (P = 0.026). Multivariable regression analysis confirmed these 4 factors as significant independent predictors of 5-year patency. Of note, there was no statistical correlation between FPB configuration (above or below knee anastomosis, in-situ versus reversed saphenous vein) and 5-year patency. There were 40 FPBs in Caucasian patients without a history of COPD receiving SVG for claudication or popliteal aneurysm that had a 92% estimated 5-year patency by Kaplan-Meier survival analysis.

CONCLUSIONS

Long-term primary patency that was substantial enough to consider open surgery as a first intervention was demonstrated in Caucasian patients without COPD, having good quality saphenous vein, and who underwent FPB for claudication or popliteal artery aneurysm.

Systematic Review and Meta-analysis of Clinical Outcomes After Endovascular Treatment in Patients With Femoropopliteal Lesions Greater Than 150 mm

OBJECTIVE

Indications for endovascular treatment of femoropopliteal (FP) lesions have steadily increased over the past decade. Accordingly, the number of devices has also increased but the choice of the best endovascular treatment remains to be defined. The aim of this meta-analysis was to summarize all studies investigating endovascular treatment of FP lesions greater than 150 mm from 2010 to 2021.

METHODS

Articles were searched using PubMed, Scopus, and Cochrane. Included studies were randomized controlled trials (RCTs), cohort studies, and case series (prospective and retrospective) that evaluated any endovascular procedure in patients with long FP lesions classified TASC (Trans-Atlantic Inter-Society Consensus document II on management of peripheral arterial disease) C and/or D, and a mean length >150 mm, primary outcome had to be the 1-year primary patency. Overall estimate of primary patency, secondary patency, and freedom from target lesion revascularization (TLR) at 1 year depending on the different devices were investigated. The meta-analysis was conducted following the requirements of the MOOSE (Meta-analysis of Observational Studies in Epidemiology) checklist.

RESULTS

Forty-four papers comprising 4847 patients and 5282 treated limbs were included. Mean lesions length ranged from 150.5 to 330 mm. The pooled 1-year primary and secondary patencies, and freedom from TLR rates were 0.71 (95% CI: 0.67-0.74), 0.87 (95% CI: 0.83-0.91), and 0.79 (95% CI: 0.74-0.84), respectively. Primary permeability at 1 year were 0.68 (95% CI: 0.62-0.73), 0.67 (95% CI: 0.60-0.74), 0.74 (95% CI: 0.64-0.84), and 0.83 (95% CI: 0.78-0.88) for bare metal stents, covered stents (CSs), drug-eluting stents, and drug-coated balloons (DCBs), respectively. Lesions treated with DCB had the highest 1-year primary patency rate.

CONCLUSIONS

At 1-year, endovascular procedures for FP lesions greater than 150 mm obtain satisfactory results. High primary patency rates were obtained with drug-coated devices, while CSs obtained less favorable results. Randomized studies comparing different devices in the treatment of long FP lesions remain necessary to determine the most optimal approach for the management of these patients.

CLINICAL IMPACT

This paper highlights on the one hand the satisfactory results of endovascular treatment on complex femoropopliteal lesions formerly reserved for conventional surgery. On the other hand, among the available devices, paclitaxel-eluting devices seem to show superior results which should make them recommended as first-line treatment.

Is the Mid-Term Patency Rate of Small-Diameter Viabahn Stent-Grafts in Peripheral Artery Disease Related to Their Length? A Systematic Review

OBJECTIVE

Small-diameter endografts can be used for the treatment of the peripheral vascular disease, but the patency rate during the follow-up is still under debate. With this review, we aimed at analyzing the mid-term patency of small-diameter Viabahn stent-grafts and investigating the relationship between patency and the length of the graft.

METHODS

We performed a review of articles published until September 2020 and reporting use of ≤7-mm-diameter Viabahn stent-grafts in diseased peripheral arteries. Data on study type, demographic, lesion length, stent-graft diameter, length, and patency (1-year, 3-year, 5-year primary patency, primary-assisted patency, and secondary patency), follow-up, endoleak, and re-intervention rates were extracted and analyzed. A statistical test was applied to identify a correlation between stent-graft length and patency.

RESULTS

16 retrospective and 7 prospective studies reported the outcome of 1613 patients (mean age: 69.6±33.7 years). There was considerable heterogeneity in reporting standards among studies. The diameter of Viabahn stent-grafts ranged 5 to 7mm and the average length was 23.6±12.4cm. Heparin-bonded grafts were used in 46.4% of cases. Mean follow-up time was 26.4±17.6 months. The 1- and 5-year primary patency rate was 75.7% (95% CI, 73.6%-77.8%) and 46.8% (95% CI, 41.0%-52.6%), respectively. The 1- and 5-year primary-assisted patency rate was 80.9% (95% CI, 73.9%-87.8%) and 60.9% (95% CI, 46.4-75.5%), respectively. The 1- and 5-year second-assisted patency was 90.4% (95% CI, 87.4%-93.3%) and 73.7% (95% CI, 64.7%-82.8%), respectively. No correlation between the stent-graft length and patency was found.

CONCLUSIONS

Small-diameter Viabahn stent-graft implantation represents a safe treatment for patients with peripheral artery disease, and the mid-term patency rate seems not be affected by the length of the graft.

CLINICAL IMPACT

The use of small diameter stent-grafts for peripheral vascular disease is an established technique but the patency rate is still under debate. With this review we have investigated the relationship between the mid-term patency and the diameter of the stent-grafts. Afterv having analysed data from 23 published studies including 1613 patients we can conclude that the treatment of the peripheral artery disease with small diameter stent-grafts is safe and the mid-term patency rate seems not be affected by the lenght of the grafts.

Endovascular bypass as a strategy for long femoropopliteal lesions

INTRODUCTION

Endovascular treatment has become the predominant treatment modality for femoropopliteal lesions. In longer and more complex lesions advanced technology is often required to improve results, with the endovascular bypass being one of them.

EVIDENCE ACQUISITION

A systematic review of the literature was performed to determine the clinical and technical outcomes of the latest generation endoprosthesis, with heparin bioactive surface and contoured proximal edge.

EVIDENCE SYNTHESIS

13 articles were enrolled: 3 randomized controlled trials, 4 prospective multicenter trials and 6 retrospective studies. The VIASTAR trial showed that the endoprosthesis has a better two-year primary patency compared to bare metal stenting, especially in long lesions (62% vs. 27%, P=0.004). The SUPERB trial showed that the endoprosthesis had similar results compared to bypass surgery, albeit with less complications (31% vs. 55%, P=0.048). The RELINE study showed that treatment with an endoprosthesis had a better one-year primary patency compared to balloon angioplasty for in-stent restenosis (75% vs. 28%, P<0.001). In the cohort studies one-year patency rates ranged from 61% to 86% for primary patency, from 65% to 92% for primary assisted patency, and from 83% to 95% for secondary patency.

CONCLUSIONS

For long femoropopliteal lesions, the heparin-bonded endoprosthesis is related to better outcomes compared to bare nitinol stents, and comparable outcomes as with the femoropopliteal bypass, but with less complications. There is a wide range in primary patency rates, with consistent high secondary patency rates. The endovascular bypass can be considered an appropriate strategy in these patients.

A review on femoropopliteal arterial deformation during daily lives and nickel-titanium stent properties

The increasing number of studies on the behaviour of stent placement in recent decades provides a clear understanding of peripheral artery disease (PAD). The severe mechanical loads (axial tension and compression, bending, radial compression and torsion) deformation of the femoropopliteal artery (FPA) is responsible for the highest failure rate of permanent nickel-titanium (Nitinol) stents. Therefore, the purpose of this article is to review research papers that examined the deformation of the natural load environment of FPA, the properties of Nitinol and mechanical considerations. In conclusion, a better understanding of mechanical behaviour for FPA Nitinol stents contributes to increased mechanical performance and fatigue-life.

Patient and Institutional Costs of Failure of Angioplasty of the Superficial Femoral Artery

BACKGROUND

Debate surrounds the optimal management of superficial femoral artery (SFA) disease. Randomized trial data rarely reflect real world findings, specifically the consequences to the patient of angioplasty failure. We observed the effect of a failed SFA angioplasty on the need for repeated clinic visits, hospital readmissions, imaging requirements, and reinterventions.

METHODS

We reviewed a consecutive series of 148 patients (94 men, median age 72 years) undergoing solely SFA angioplasty over a 2-year period. Patient preangioplasty demographics and 2-year post-PTA follow-up data were collated, including hospital attendances (inpatient/outpatient), further imaging (including radiation exposure) and revascularization attempts. We defined "failed angioplasty" as presence of clinical symptoms with radiological evidence of significant restenosis after an initial successful primary SFA angioplasty.

RESULTS

Fifty-four patients represented with a failed angioplasty (median time of 4 months after index PTA). In this group, failure of index angioplasty resulted in a further 185 restenosis-related clinic visits and a total of 537 bed days of inpatient stay. This group underwent a further 149 imaging events and required a further 34 endovascular revascularization procedures and 12 infrainguinal bypass procedures. These interventions and investigations corresponded to overall effective radiation dose across all patients of 190.69 mSv. Of the cohort of 99 patients who did not have a "failed angioplasty," they required 100 clinic visits, 21 further scans (total radiation dose 6.42 mSv), and 36 bed days of inpatient admission.

CONCLUSIONS

Failed angioplasty results in significant additional consequences for patients and health-care systems. Further work should focus on refining decision-making, providing the right procedure to the right patient at the right time.

Heparin-Bonded Stent-Graft for the Treatment of TASC II C and D Femoropopliteal Lesions: 36-Month Results of the Viabahn 25 cm Trial

PURPOSE

To evaluate the 36-month technical and clinical outcome after implantation of the 25-cm Viabahn endoprosthesis with Propaten bioactive surface in TransAtlantic Inter-Society Consensus II C and D lesions of the superficial femoral and proximal popliteal arteries.

MATERIALS AND METHODS

This prospective, multicenter, single-arm trial (ClinicalTrials.gov; identifier NCT01263665) enrolled 71 patients (mean age 66.7±8.3 years; 50 men) with lifestyle-limiting claudication or rest pain (Rutherford category 2-4) and long (>20-cm) lesions of the superficial femoral and proximal popliteal arteries. Primary endpoint was primary patency at 36 months. Secondary endpoints included primary assisted patency; secondary patency; freedom from target lesion revascularization (TLR); freedom from a composite of death, target vessel revascularization (TVR), and amputation; clinical success; and freedom from device fracture.

RESULTS

Primary patency estimated by Kaplan-Meier analysis was 40.6% at 36 months. Primary assisted patency and secondary patency estimates were 53.0% and 96.9%, respectively. Within 36 months, 27 patients had to undergo a TLR. Twenty-five patients (35.2%) had a TVR. Freedom from the composite of death, TVR, and amputation endpoint was 44.5%. The estimate of the sustained clinical success with stable or improved Rutherford category was 58.5%. No stent fracture was detected during follow-up.

CONCLUSION

The primary patency rate without reintervention after treatment of long femoropopliteal lesions is low. However, secondary patency after implantation of a Viabahn endoprosthesis is high and seems to be superior to the use of other revascularization techniques, resulting in persistent clinical improvement.

Use of heparin coated vascular stents in femoropopliteal chronic total occlusions: Long term outcomes

PURPOSE

To evaluate the long-term clinical efficacy of the Tigris © stent (Gore ©) in femoropopliteal chronic total occlusions (CTOs).

MATERIAL AND METHODS

This single centre retrospective study included 29 patients treated with 47 Tigris© stents for CTOs. Lesion location, type, length, revascularisation method, smoking status and diabetes were reviewed. Clinical follow-up was performed. Primary safety points were complications and adverse events. Secondary efficacy points were symptom deterioration, freedom from target lesion revascularization (TLR) and amputation rate. Freedom from TLR was evaluated with Kaplan-Meier analysis; Cox multivariable logistic regression analysis of the factors associated with stent re-occlusion was also performed.

RESULTS

All procedures were technically successful without any peri- or post-procedural complications and adverse events. Median follow-up was 48 months (range: 7-70). Lesions were located in the superficial femoral (19), popliteal (3) and femoropopliteal (7) arteries with mean lesion length 13.9 ± 7.6 cm. In 12 patients subintimal recanalization was performed. Freedom from TLR rates at 6, 12, 18, 24 and 36 months were 96.6 %, 85.7 %, 81.9 %, 78.2 % and 74.3 % respectively. No stent fracture was observed and no amputation was performed in any of the patients. Smoking status, the presence of diabetes, lesion localization and recanalization type were not associated with stent re-occlusion.

CONCLUSION

This study demonstrated that use of a heparin coated vascular stent for femoropopliteal CTOs appears to offer satisfactory long-term results.

Predictors of long-term outcomes after polytetrafluoroethylene-covered stent-graft repair of peripheral arterial aneurysms, pseudo-aneurysms, and arterio-venous fistulas

OBJECTIVES

To evaluate the primary patency rate at three years for the infra-aortic peripheral arterial pathologies treated with polytetrafluoroethylene-covered stent-grafts.

METHODS

Patients treated with self-expandable polytetrafluoroethylene-covered stent-grafts for infra-aortic peripheral arterial aneurysms, pseudo-aneurysms, and arterio-venous fistulas were evaluated retrospectively. A total of 48 patients (35 male, 13 female; mean age: 53.8 ± 13.5) were included with 29.0 ± 16.5 months (median 27, range 4-70) mean follow-up period. The primary objective was to determine the primary patency rate at three years. The secondary objectives were to compare type and localization of pathology, and length and diameter of the stent-grafts with primary patency rate. Kaplan-Meier test was used as the main statistical method.

RESULTS

Overall mean primary patency rate at three years was 77.10%. Polytetrafluoroethylene-covered stent-graft implantation in aneurysms had worse primary patency rate than pseudo-aneurysms and arterio-venous fistulas (66.6%, P = 0.03; 76.9%, P = 0.03; 88.2%, P = 0.01, respectively). Stent-graft location, length, and diameter are not associated with primary patency rate (P > 0.05) but stent diameter is associated with better primary assisted and secondary patency rates (P < 0.05).

CONCLUSIONS

Pathology of the lesion is associated with the long-term primary patency rate of polytetrafluoroethylene-covered stent-grafts but not the stent-graft location, length, or diameter. Stent diameter is associated with primary assisted and secondary patency rates.

Midterm Outcomes of Drug-Coated Balloon Angioplasty in Femoropopliteal Lesions in a Daily Practice Cohort

BACKGROUND

Most previous drug-coated balloon (DCB) angioplasty studies used strict inclusion and exclusion criteria and therefore might not be representative for daily practice. This study was performed to evaluate the midterm outcomes of DCB angioplasty in femoropopliteal artery disease and to identify risk factors for restenosis.

MATERIALS AND METHODS

All patients treated with DCB angioplasty between January 2015 and September 2016 were included. Provisional stents were placed if indicated. Data were retrospectively collected from digital patient records. No exclusion criteria were applied. The primary end point was primary patency. Secondary end points were primary assisted patency, secondary patency, clinically driven target lesion revascularization (CD-TLR) and major adverse events. All end points were calculated with the Kaplan-Meier analysis. The univariable and multivariable Cox regression analyses were performed to identify risk factors for restenosis.

RESULTS

A total of 109 patients (113 legs) were included (45% male; mean age, 72 ± 10). The rate of critical limb ischemia was 52% and total occlusions were treated in 38%. The mean follow-up was 24 ± 13 months. Primary patency rates were 87%, 79%, and 61% at 1, 2, and 3 years, respectively. Primary assisted patency rates were 95%; 89%, and 79%; secondary patency rates were 99%, 97%, and 91%; and CD-TLR rates were 6.9%, 14.3%, and 20.6% at 1, 2, and 3 years, respectively. Overall mortality and major target limb amputation rates were 18% and 5% at 3 years. Multivariable analysis demonstrated that only Trans-Atlantic Inter-Society Consensus (TASC) D lesions were associated with restenosis (P = 0.008).

CONCLUSIONS

DCB angioplasty is an effective and safe treatment option for femoropopliteal lesions in daily practice with excellent 1- and 2-year results. The 3-year results were slightly less favorable, which may be caused by the ongoing vascular disease or a late "catch-up" phenomenon. Only TASC D lesions were associated with loss of primary patency after adjustment for confounders.

Comparison of Bypass and Endovascular Intervention for Popliteal Occlusion with the Involvement of Trifurcation for Critical Limb Ischemia

BACKGROUND

The aim of this study is to analyze the technical aspects and outcomes of the treatment of occlusion of the popliteal artery with the involvement of the trifurcation treated with a bypass (open) and endovascular (endo) approach.

METHODS

Overall, 108 consecutive procedures were enrolled retrospectively. Patients were evaluated in 2 groups: the endo group (65 patients) and the open group (43 patients). Primary outcome were MALE (major adverse limb events), amputation-free survival, and early mortality (until 30 days). Secondary outcome was overall survival in 3 years. Inclusion criteria were Rutherford 4 and 5 and occlusion of the popliteal artery with the involvement of trifurcation and, at least, 1 infrapopliteal artery of runoff.

RESULTS

Technical success was achieved in 100% of patients in the open and 96.9% of patients in the endo group. Freedom from MALE was 73.5% and 68.5% for 1 and 3 years respectively for the endo group, and 84.3% and 77.2% respectively for the open group (P = 0.413). Considering the total number of major reinterventions executed until 3 years, the reinterventions was statistically more performed in the endo compared to the open group (P = 0.0459). Amputation-free survival for the endo group in 30 days, 1 year, and 3 years was 93.7%, 79.3%, and 66.0%, respectively, and the amputation-free survival for the open group was 88.4%, 77.4%, and 64.3% (P = 0.726). Early mortality was 9.3% for the open group and 1.5% for the endo group (P = 0.060). In 3 years, the overall survival was 75.1% in the open group and 84.3% in the endo group.

CONCLUSIONS

In 3 years, follow-up endovascular treatment of occlusion of the popliteal artery with the involvement of the trifurcation has similar time freedom from MALE compared to open approach. Overall and amputation-free survival was not different between the groups besides more reinterventions in patients who underwent endovascular approach.

Long-term results of the heparin-bonded Viabahn stent graft in femoropopliteal TASC C and D lesions with a covered stent length of minimum 25 cm

Background

Heparin-bonded covered stent grafts (Viabahn) are used to treat femoropopliteal long-segment arteriosclerotic lesions. The aim of this study was to evaluate the long-term outcome of Viabahn grafts with a covered stent length of minimum 25 cm.

Methods

We conducted a retrospective analysis of patients receiving a heparin-bonded stent graft in our clinic who met the length criteria between July 2010 and March 2018. Primary endpoints were patency rates, limb salvage and survival after five years. Secondary endpoint was the 30-day outcome including early complications.

Results

A total of 62 patients (45 male, median age 70.5 years) were included. The median arteriosclerotic lesion length was 25 cm (22.0–41.3 cm), the minimum covered stent length was 25 cm (25–46 cm). All lesions were TASC C and D lesions. The 30-day mortality was 0%, an early stent graft occlusion occurred in 8.1%. A major amputation was performed in 1.6%. Primary patency, primary assisted patency, secondary patency, limb salvage and survival were 38.5%, 45.7%, 52.4%, 92.8% and 68.9% after five years. Distal stent graft end below the femoral condyles and critical limb ischemia was associated with a significant decreased survival. The diameter of the stent had no influence on the outcome.

Conclusion

The Viabahn stent graft for long segment arteriosclerotic lesions is a feasible treatment with adequate long-term results.

Edge Stenosis After Covered Stenting for Long Superficial Femoral Artery Occlusive Disease: Risk Factor Analysis and Prevention With Drug-Coated Balloon Angioplasty

Purpose: To report a retrospective analysis of risk factors for edge restenosis after Viabahn stent-graft treatment of superficial femoral artery (SFA) occlusive disease and determine any protective effect of drug-coated balloons (DCBs) used at the time of stent-graft implantation. Methods: Between October 2011 and July 2016, 110 patients (mean age 73.3±7.6 years; 78 men) were treated with the Viabahn stent-graft for long SFA occlusions. Thirty-eight (34.5%) patients had DCB reinforcement at the distal edge of the stent-graft. For analysis, the population was divided into groups of no edge stenosis patients (n=88; mean lesion length 22.4±4.2 cm) and edge stenosis patients (n=22; mean lesion length 23.5±5.7 cm). The clinical outcomes, ankle-brachial indices, computed tomography angiography findings, and patency were compared at a minimum of 12 months. Logistic regression analysis was employed to determine risk factors for edge stenosis; the results are presented as the odds ratio (OR) and 95% confidence interval. Results: No differences in clinical or procedural characteristics were identified except the higher incidence of diabetes (p=0.008) and greater need for retrograde access (p=0.033) in the edge stenosis group. DCB reinforcement reduced the incidence of edge stenosis (p=0.021) and target lesion revascularization (TLR; p=0.010) and resulted in a significantly higher 1-year primary patency rate (92.1% vs 76.4%, p=0.042). However, multivariate analysis revealed only poor distal runoff (OR 0.31, 95% CI 0.11 to 0.83, p=0.020) as a predictor of edge stenosis. Conclusion: The risk of edge stenosis after Viabahn implantation was higher in patients with poor distal runoff. DCB reinforcement over the distal edge reduced edge stenosis, decreased 1-year TLR, and improved 1-year primary patency.

Endovascular Treatment of Severely Calcified Femoropopliteal Lesions Using the “Pave-and-Crack” Technique: Technical Description and 12-Month Results

Purpose: To report midterm results of the “pave-and-crack” technique to facilitate safe and effective scaffolding of heavily calcified femoropopliteal lesions in preparation for delivery of a Supera interwoven stent. Methods: Data were collected retrospectively on 67 consecutive patients (mean age 71±8 years; 54 men) treated with this technique between November 2011 and February 2017 at a single center. A third (22/64, 34%) of the patients had critical limb ischemia (CLI). Most lesions were TASC D (52/67, 78%), and the majority were occlusions (61/66, 92%). The mean lesion length was 26.9±11.2 cm. Nearly two-thirds (40/64, 62%) had grade 4 calcification (Peripheral Arterial Calcium Scoring System). To prepare for Supera stenting, the most heavily calcified segments of the lesion were predilated aggressively to obliterate recoil. A Viabahn stent-graft was then implanted to “pave” the lesion and protect from vessel rupture as aggressive predilation continued until the calcified plaque was “cracked” before lining the entire lesion with a Supera stent. Patency and target lesion revascularization (TLR) rates were estimated using the Kaplan-Meier method. Results: Procedural success was achieved in 100% and technical success (residual stenosis <30%) in 98% (66/67). The mean cumulative stent lengths were 16±9 cm for the Viabahn and 23±12 cm for the Supera. Only 2 complications occurred (distal embolization and access-site pseudoaneurysm). Two CLI patients died within 30 days, and 3 patients (all claudicants) underwent a TLR. Patients were followed for a mean 19±18 months, during which another 2 CLI patients died and 1 patient had a major amputation. One-year primary and secondary patency estimates were 79% and 91%, respectively; freedom from TLR was 85%. Conclusion: Despite severe lesion calcification, patients experienced high technical success and a safe and durable therapy at midterm follow-up with the femoropopliteal “pave-and-crack” technique.

Nitinol Stents in the Femoropopliteal Artery: A Mechanical Perspective on Material, Design, and Performance

Endovascular stenting has matured into a commonly used treatment for peripheral arterial disease (PAD) due to its minimally invasive nature and associated reductions in short-term morbidity and mortality. The mechanical properties of the superelastic Nitinol alloy have played a major role in the explosion of peripheral artery stenting, with modern stents demonstrating reasonable resilience and durability. Yet in the superficial femoral and popliteal arteries, even the newest generation Nitinol stents continue to demonstrate clinical outcomes that leave significant room for improvement. Restenosis and progression of native arterial disease often lead to recurrence of symptoms and reinterventions that increase morbidity and health care expenditures. One of the main factors thought to be associated with stent failure in the femoropopliteal artery (FPA) is the unique and highly dynamic mechanical environment of the lower limb. Clinical and experimental data demonstrate that the FPA undergoes significant deformations with limb flexion. It is hypothesized that the inability of many existing stent designs to conform to these deformations likely plays a role in reconstruction failure, as repetitive movements of the leg and thigh combine with mechanical mismatch between the artery and the stent and result in mechanical damage to both the artery and the stent. In this review we will identify challenges and provide a mechanical perspective of FPA stenting, and then discuss current research directions with promise to provide a better understanding of Nitinol, specific features of stent design, and improved characterization of the biomechanical environment of the FPA to facilitate development of better stents for patients with PAD.

Use of the Gore Tigris Vascular Stent in Advanced Femoropopliteal Peripheral Arterial Disease

PURPOSE

To prospectively evaluate the safety and efficacy of using the Tigris vascular stent (Gore, Flagstaff, Arizona) alone or in combination with the Viabahn stent (Gore) for revascularizing femoropopliteal Trans-Atlantic Intersociety Consensus (TASC) type B-D lesions with varying degrees of calcification.

MATERIALS AND METHODS

Patients with Rutherford stage ≥ 3 and TASC type ≥ B were included in the study. From January 2015 to April 2017, 31 segments in 31 patients (21 men, ovarall mean age 73.3 ± 9.2 years) were treated. The breakdown by TASC type and Rutherford stage were TASC B (n = 12), C (n = 6), and D (n = 13), and Rutherford 3 (n = 28) and 4 (n = 3). The lesions were located in the common femoral artery (n = 1), superficial femoral artery (SFA; n = 20), distal SFA to P1 (n = 3), popliteal P1 (n = 1), popliteal P1-3 (n = 3), popliteal P2-3 (n = 2), and 1 femoropopliteal bypass. There were 18 occlusions (58.1%) and 13 stenoses (41.9%). The mean diseased segment length was 15.5 ± 9.9 cm with 80.6% of moderate/severe calcification. The follow-up consisted of color Doppler ultrasound and clinical assessment at 1, 3, 6, 9, 12, and 15 months.

RESULTS

Technical success was 100%. There were no periprocedural or postprocedural complications. The mean stented lesion length was 17.2 ± 10.5 cm with a mean follow-up of 13.1 ± 6.9 months. Primary patency rates at 6, 9, 12, and 15 months were, respectively, 100% (24/31 patients), 90.5% (21/31 patients), 88.9% (20/31 patients), and 80% (15/31 patients). The median postprocedural Rutherford stage was 1. Three occlusions occurred at 7, 9, and 14 months, leading to a target lesion revascularization of 9.7% and a secondary patency of 100% at 15 months. Logistic analysis results demonstrated that lesion length (P = .003) was associated with reocclusion. Amputation-free survival at 15 months was 100%. Intrastent restenosis was observed in four cases (12.9%) but none were associated with worsening of symptoms. No stent fractures were observed.

CONCLUSIONS

The Tigris stent used alone or in combination with a Viabahn stent for femoropopliteal TASC B-D lesions demonstrated acceptable 12-month primary patency with a low reintervention rate.

Advanced Stent Graft Treatment of Venous Stenosis Affecting Hemodialysis Vascular Access: Case Illustrations

Surgically placed dialysis access is an important component of dialysis replacement therapy. The vast majority of patients undergoing dialysis will have surgically placed accesses at some point in the course of their disease, and for many patients these accesses may represent their definitive renal replacement option. Most, if not all, arteriovenous fistulae and grafts will require interventions at some point in time. Percutaneous angioplasty is the typical first treatment performed for venous stenoses, with stents and stent grafts being reserved for patients in whom angioplasty and surgical options are exhausted. In some salvage situations, stent graft placement may be the only or best option for patients. This article describes, using case illustrations, placement of stent grafts in such patients; a focus will also be made on the techniques utilized in such salvage situations.