Long-term Patency and Clinical Outcome of the Viabahn Stent-Graft for Femoropopliteal Artery Obstructions

Superficial femoral artery-anterior tibial artery bypass with great saphenous vein grafting via the lateral femoropopliteal route for infection after Viabahn placement

We report a case involving an elderly man who successfully underwent superficial femoral artery-anterior tibial artery bypass via the lateral femoropopliteal route following development of a stent infection after placement of a small-diameter covered stent for a ruptured superficial femoral artery pseudoaneurysm. This report suggests that appropriate treatment strategies for device infection subsequent to device removal are paramount for the prevention of reinfection and preservation of the affected extremity.

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.

Results After Open and Endovascular Repair of Popliteal Aneurysm: A Matched Comparison Within a Population Based Cohort

OBJECTIVE

To identify factors affecting the outcome after open surgical (OSR) and endovascular (ER) repair of popliteal artery aneurysm (PA) in comparable cohorts.

METHODS

A matched comparison in a national, population based cohort of 592 legs treated for PA (2008 - 2012), with long term follow up. Registry data from 899 PA patients treated in 2014 - 2018 were analysed for time trends. The 77 legs treated by ER were matched, by indication, with 154 legs treated with OSR. Medical records and imaging were collected. Analysed risk factors were anatomy, comorbidities, and medication. Elongation and angulations were examined in a core lab. The main outcome was occlusion.

RESULTS

Patients in the ER group were older (73 vs. 68 years, p = .001), had more lung disease (p = .012), and were treated with dual antiplatelet therapy or anticoagulants more often (p < .001). The hazard ratio (HR with 95% confidence intervals) for occlusion was 2.69 (1.60 - 4.55, p < .001) for ER, but 3.03 (1.26 - 7.27, p = .013) for poor outflow. For permanent occlusion, the HR after ER was 2.47 (1.35 - 4.50, p = .003), but 4.68 (1.89 - 11.62, p < .001) for poor outflow. In the ER subgroup, occlusion was more common after acute ischaemia (HR 2.94 [1.45 - 5.97], p = .003; and poor outflow HR 14.39 [3.46 - 59.92], p < .001). Larger stent graft diameter reduced the risk (HR 0.71 [0.54 - 0.93], p = .014). In Cox regression analysis adjusted for indication and stent graft diameter, elongation increased the risk (HR 1.020 per degree [1.002 - 1.033], p = .030). PAs treated for acute ischaemia had a median stent graft diameter of 6.5 mm, with those for elective procedures being 8 mm (p < .001). Indications and outcomes were similar during both time periods (2008 - 2012 and 2014 - 2018).

CONCLUSION

In comparable groups, ER had a 2.7 fold increased risk of any occlusion, and 2.4 fold increased risk of permanent occlusion, despite more aggressive medical therapy. Risk factors associated with occlusion in ER were poor outflow, smaller stent graft diameter, acute ischaemia, and angulation/elongation. An association between indication, acute ischaemia, and small stent graft diameter was identified.

Effectiveness of combined superficial femoral artery endovascular therapy with popliteal-to-distal bypass: A paradigm shift in surgical open bypass for chronic limb-threatening ischemia

OBJECTIVES

The purpose of this study was to evaluate the results of combining superficial femoral artery endovascular therapy with distal bypass originating from the popliteal artery as a method of lower extremity revascularization in patients with chronic limb-threatening ischemia.

METHODS

The records of patients undergoing combined superficial femoral artery endovascular therapy with popliteal-to-distal bypass for chronic limb-threatening ischemia from January 2014 to April 2020 at a single institution were retrospectively reviewed. The patients' background, operative details, and long-term outcomes were analyzed.

RESULTS

Fifty-two popliteal-to-distal bypasses with superficial femoral artery endovascular therapy were performed in 49 patients (33 men; mean age, 76 ± 9 years; diabetes mellitus, 80%; end-stage renal disease with hemodialysis, 47%). The Trans-Atlantic Inter-Society Consensus II classification of superficial femoral artery-popliteal lesion was "A" in 8 (15%) patients, "B" in 14 (27%) patients, "C" in 24 (46%) patients, and "D" in 6 (12%) patients. The intervention for superficial femoral artery lesions was plain old balloon angioplasty in 4 patients, self-expandable nitinol stent in 15 patients, drug-coated balloon in 18 patients, drug-eluting stent in 4 patients, stent graft in 10 patients, and interwoven nitinol stent in 1 patient. Distal bypass originated from the above-knee popliteal artery in 9 (17%) limbs and the below-knee popliteal artery in 43 (83%) limbs. The most common outflow artery was the posterior tibial artery (44%). The mean follow-up period was 17 ± 17 months. The primary and secondary patency of the graft was 44% and 72%, respectively, at 1 year and 39% and 72%, respectively, at 3 years. Primary patency and freedom from clinical-driven target lesion revascularization of superficial femoral artery endovascular therapy lesions were 85% and 90%, respectively, at 1 year and 63% and 75%, respectively, at 3 years. Limb salvage was 97% at 1 year and 92% at 3 years. Wound healing was 67% at 6 months and 83% at 12 months.

CONCLUSIONS

Combined superficial femoral artery endovascular therapy with popliteal-to-distal bypass may be a promising approach for patients with chronic limb-threatening ischemia because of durable patency, acceptable wound healing, and good limb salvage.

Outcomes after Endovascular Stent Placement for Long-Segment Superficial Femoral Artery Lesions

BACKGROUND

Endovascular intervention is commonly pursued as first-line management of symptomatic, long-segment superficial femoral artery (SFA) disease. The relative effectiveness and comparative long-term outcomes among bare metal stents (BMS), covered stents (CS), and drug-eluting stents (DES) for long-segment SFA lesions remain uncertain.

METHODS

A retrospective cohort study identified patients with symptomatic SFA lesions measuring at least 15 cm in length who successfully received an endovascular stent (BMS, CS, or DES). The outcomes were patency, patient presentation upon stent occlusion, amputation-free survival (AFS), and all-cause mortality. Proportional hazards regressions and a multinomial logistic regression model were used to control for significant confounders.

RESULTS

A total of 226 procedures were analyzed (BMS: 95 [42%]; CS: 74 [33%]; DES: 57 [25%]). There were no significant differences among the 3 stent types with respect to age, prevalence of either diabetes or end-stage renal disease, or smoking history. The median length of the SFA lesion varied across the cohorts (BMS: 28 cm [interquartile range, IQR 20-30]; CS: 26 cm [IQR 20-30]; DES: 20 cm [IQR 16-25]; P = 0.002). The unadjusted primary patency of BMS at 12, 24, and 48 month following index stent placement was 57%, 47%, and 44%, respectively. This is compared to 62%, 49%, and 42% for CS, and 81%, 66%, and 53% for DES, respectively (log-rank P = 0.044). In adjusted models, however, there were no significant differences in primary patency among the stent types. Compared to CS however, DES was associated with improved primary-assisted patency (hazard ratio [HR] for patency loss: 0.35, P = 0.008) and secondary patency (HR: 0.32, P = 0.011). Across the entire follow-up period, stent occlusions occurred in 38 (40%) BMS cases, 42 (57%) CS, and 11 (19%) DES (P < 0.001). Of these, acute limb ischemia (ALI) occurred in 2 (5%) BMS cases, 14 (33%) CS, and 1 (9%) DES (P = 0.010). After adjustment, the relative risk of presenting with ALI as opposed to claudication was 27 times greater among patients re-presenting with occluded CS compared to BMS (P = 0.020). There were no significant differences in AFS or all-cause mortality across the 3 cohorts.

CONCLUSIONS

For long-segment SFA lesions, DES is associated with improved primary-assisted and secondary patency over long-term follow-up. In the event of stent occlusion, CS is associated with an increased risk of ALI.

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.

Drug-coated balloon versus plain old balloon angioplasty in femoropopliteal disease: An updated meta-analysis of randomized controlled trials

BACKGROUND

Drug-coated balloon (DCB) angioplasty has emerged as a mainstay of therapy for the treatment of peripheral arterial disease (PAD) involving the superficial femoral and popliteal arteries. We performed a meta-analysis including all available randomized controlled trials (RCTs) to date which compare DCB to plain balloon angioplasty (POBA) in femoropopliteal disease (FPD).

METHODS

Five databases were analyzed including EMBASE, PubMed, Cochrane, Scopus, and Web-of-Science from January 2000 to September 2018 for RCTs comparing DCB to POBA in patients with FPD. Heterogeneity was determined using Cochrane's Q-statistics. Random effects model was used.

RESULTS

Twenty-two RCTs, including five trials of in-stent restenosis (ISR) intervention, with 3,217 patients were included in the analysis. Mean follow-up was approximately 21.6 ± 14.4 months. Overall, DCB use was associated with a 51% reduction in target vessel revascularization (TLR) when compared to POBA at follow-up (relative risk [RR]: 0.49, 95% confidence interval [CI]: 0.40-0.61, P < 0.0001). Rates of TLR were 45% lower in the DCB group when compared to POBA in patients with ISR (RR: 0.55, 95% CI: 0.37-0.81, P = 0.002). DCB was associated with lower rates of binary stenosis, late lumen loss and higher primary safety endpoints. Major amputation and mortality were not different between DCB and POBA.

CONCLUSIONS

Use of DCBs is associated with improved vessel patency and a lower risk of TLR when compared to POBA in patients with FPD, especially in the setting of ISR. There was no difference in mortality between DCB and POBA in our meta-analysis. Extended follow-up of the available RCT data will be essential to analyze long-term device-related mortality.

Hybrid Viabahn-Assisted Bypass for Long Femoro-Popliteal Occlusive Disease - Midterm Results

BACKGROUND

Endovascular therapy has become the first-line treatment for most peripheral artery diseases, but re-entry into the true lumen is not always possible, particularly in some cases of chronic total occlusion (CTO). We previously reported a novel hybrid Viabahn-assisted bypass (VAB) technique to facilitate revascularization of the femoro-popliteal CTO. This study assessed the midterm results of VAB technique.Methods and Results:Between January 2013 and April 2017, 440 patients received femoro-popliteal intervention and 17 of them (mean age, 76.2 years; 11 male patients) were treated using the VAB technique. The technical success was 100%. The mean follow-up period was 27.4±14.4 months (range, 6-50 months). Two patients underwent major amputation at 6 and 11 months postoperatively, but they died of acute myocardial infarction and of sepsis, respectively. Another 3 patients received re-intervention because of edge stenosis of the Viabahn stent graft. Another patient had acute Viabahn thrombosis and was treated using open thrombectomy. The primary and secondary patency rates at 12 months were both 88.2%, and at 24 months they were 69.2% and 84.6%, respectively.

CONCLUSIONS

The VAB technique could be a safe and feasible alternative treatment for long femoro-popliteal CTO when conventional treatments fail. The technical success is high, and the midterm patency rates are acceptable.

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.

Jetstream XC Device for Treatment of Long Viabahn Stents Occlusions in the Superficial Femoral Artery: A Report of Two Cases

Repeated restenotic events are common in superficial femoral artery and as of late, Viabahn stent grafts have been FDA (U.S. Food & Drug Administration) approved. Viabahn have been particularly attractive given that they provided a physical barrier for the development of neointimal hyperplasia. This particular feature however, also underscores one of the main limitations of the therapy; providing a physical barrier of collateral circulation and predisposing to acute limb ischemia. Viabahn endograft thrombosis is characterized by stent edge stenosis and endograft thrombosis. Here we present 2 cases of Viabahn graft thrombosis successfully treated with the Jetstream atherectomy device, a rotational cutter with aspiration capacity.

Angiographic classification of patterns of restenosis following femoropopliteal artery intervention: A proposed scoring system

OBJECTIVES

To propose a classification system for characterizing angiographic femoropopliteal artery restenosis patterns associated with common endovascular modalities.

BACKGROUND

Peripheral artery disease is a worldwide issue affecting millions of people. Despite a myriad of endovascular technologies available to treat peripheral artery disease of the femoropopliteal arteries, restenosis remains a common failure mode. Characterizing common patterns of restenosis is important to discern the potential impact of baseline patient, lesion, and procedural characteristics, as well as treatment modalities on either the primary success or the failure patterns associated with restenosis.

METHODS

Studies included in the analysis were from previous core laboratory-adjudicated femoropopliteal artery disease trials and registries reflecting a wide array of treatment modalities.

RESULTS

From the subjects enrolled and analyzed, there were 403 total angiograms for analysis and adjudication. Target lesion revascularization images of the 32 validation cases were evaluated for index treated length, diameter stenosis, and lesion morphology characteristics. The following lesion types are proposed: Type 1 "Focal" pattern, which may be "Edge Proximal" or "Edge Distal" depending on location; a Type 2 "Multifocal" pattern which may also exhibit edge restenosis, but may also be "Edge Bilateral"; a Type 3 "Moderate" pattern and a Type 4 "Diffuse" pattern; and finally, a Type 5 "Occlusion".

CONCLUSIONS

A classification system that enables healthcare professionals to anticipate and describe failures following the index procedure, thereby impacting the choice of options for retreatment, may facilitate consistency and standardization within the heterogeneous field of endovascular device treatments for the femoropopliteal artery.

Clinical features and patency rates of Remedy® biodegradable peripheral stents

Objective:

The aim of this study was to investigate the mid-term results of Remedy® biodegradable stents, which have recently come into use for lower-extremity arterial occlusive disease.

Methods:

Sixty-five patients, who underwent surgical intervention in various cardiovascular surgery clinics throughout Turkey, were included in the study. The total number of stents used was 92. The mean age of the patients was 64.11 ± 24.13 years (20–82), and 16 (24.6%) were female. The mean number of stents per patient was 1.42, and 70.7% of the lesions were TASC type A. Patients were followed for a mean of 32 months. Sixty-five patients underwent a control examination using either digital subtraction angiography or colour Doppler ultrasonography. In-stent restenosis was defined as ≥ 50% stenosis in the stent area in asymptomatic patients. The procedure was repeated if the degree of stenosis was ≥ 70%.

Results

During the follow-up period, restenosis (≥ 50% stenosis) was observed in seven patients (10.7%). The patency rate after secondary intervention was 100%, and there was no loss of limbs in any patient. Restenosis was observed in six patients with superficial femoral artery stents, and in one patient with a popliteal arterial stent.

Conclusion

Our experience shows that Remedy® biodegradable peripheral stents were safe and effective in our cohort of patients, with acceptable patency rates.

Treatment of a massive left femoral arteriovenous malformation using an innovative modular hybrid bifurcated stent graft system

BACKGROUND

Arteriovenous malformations (AVMs) are difficult to treat and manage because of their high recurrence and complication rates. In particular, peripheral AVMs pose multiple clinical challenges because of their high flow rates and the frequent presence of multifocal nidi.

METHODS

A 37-year-old man with a massive AVM involving the left common, deep, and superficial femoral arteries and veins is discussed herein. After initially being treated at another facility with coil embolization in 2005, he went untreated until he presented to us in April 2012 with swelling, tissue breakdown, leg ulcers, pain, and difficulty walking. When our extensive packed coil embolization proved ineffective, we knew that other standard treatments would be impractical, given the size of the AVM. Because the patient was in significant danger of bleeding, we treated him endovascularly with a system of modified stent grafts to exclude the arterial branches feeding multiple nidi.

RESULTS

Postoperative computed tomography angiography scans revealed exclusion of the AVM and excellent flow to the deep and superficial femoral arteries. At 6 months postoperatively, the patient had no complications, and the leg continued to decompress. At 8 months postoperatively, we started additional treatment using percutaneous sclerotherapy to treat residual areas.

CONCLUSION

A modular hybrid bifurcated stent graft system is a viable option to treat or manage complex peripheral arteriovenous malformations.

Management of subclavian artery in-stent restenosis

Stenotic and occlusive diseases of the subclavian and brachiocephalic arteries can cause a significant morbidity as it can lead to symptomatic ischemia affecting the upper extremities, brain and, in some cases, the heart. An endovascular approach with primary stenting or provisional stenting has become the primary modality of revascularization of subclavian artery stenosis. In-stent restenosis can be treated with percutaneous transluminal angioplasty or repeat stenting and although stents offer superior long-term patency over balloon angioplasty alone for de novo lesions, there are no data regarding primary versus provisional stenting in subclavian in-stent restenosis. Here we describe a case of subclavian in-stent restenosis treated with just balloon angioplasty and demonstrate that provisional stenting with angioplasty alone when the percutaneous transluminal angioplasty results are excellent is a reasonable alternative to primary stent placement for subclavian in-stent restenosis.

Is There an Alternative to the Surgical Above-Knee Bypass in Treatment of Superficial Femoral Artery Disease? Experiences With Viabahn Stent Graft

Objective:

We conducted a retrospective study to compare short- and mid-term patencies of Viabahn with surgical above-knee prosthetic bypass (pAKB).

Methods:

The records of 52 patients with either pAKB (n = 25) or Viabahn (n = 27) were reviewed. The majority had Rutherford clinical grade 3. Patients were followed after 3, 6, and 12 months and yearly thereafter.

Results:

For Viabahn, the short-term (1-16 months) primary patency rate was 60% with a secondary patency rate of 90%, and mid-term (1-68 months) patencies of 47% and 83.3%, respectively. In pAKB, the short-term results revealed a primary patency rate of 78% with a secondary patency of 91% and mid-term results of 65% and 90%, respectively. No statistical difference was found concerning short-term patencies. Mid-term primary patency was lower for Viabahn ( P < .05) and secondary patency proved no significant difference.

Conclusion:

Viabahn revealed similar short-term primary and secondary patencies but lower mid-term primary patency. It provides a good alternative therapy to pAKB.

Angiographic characteristics of femoropopliteal in-stent restenosis: association with long-term outcomes after endovascular intervention

OBJECTIVES

The purpose of this study was to identify the relationship between angiographic patterns of restenosis and outcomes after endovascular treatment of femoro-popliteal in-stent restenosis (FP-ISR).

BACKGROUND

ISR is a frequent clinical problem after femoro-popliteal stenting.

METHODS

This was a single center study of all endovascular interventions for FP-ISR from 2006 to 2012. Class I ISR was defined as focal lesions ≤50 mm; Class II ISR as lesions > 50 mm; and Class III ISR as stent chronic total occlusion. Recurrent ISR was defined as peak systolic velocity ratio > 2.4 by duplex ultrasound.

RESULTS

Among 75 cases of FP-ISR, 28 (37%) were Class I, 22 (29%) were Class II, and 25 (33%) were Class III. The mean lesion length was 26 mm for Class I, 135 mm for Class II, and 178 mm for Class III ISR. Patients with Class III ISR more frequently had ISR extending into both the superficial femoral and popliteal artery (48% vs. 18%, P = 0.005). Balloon angioplasty was used most frequently to treat Class I ISR, while adjunctive atherectomy and/or stenting was used for almost all cases of Class III ISR. During 2-year follow-up, rates of repeat restenosis were 39% for Class I, 67% for Class II, and 72% for Class III ISR (P = 0.04). Rates of stent occlusion were 8% for Class I, 11% for Class II, and 52% for Class III ISR (P = 0.009). Class III ISR was associated with significantly increased risk of recurrent ISR (HR 2.4, 95% CI 1.1-5.6) and recurrent occlusion (HR 5.8, 95% CI 1.8-19.0) compared to other types of ISR.

CONCLUSION

Angiographic patterns of FP-ISR are important determinants of subsequent outcomes. Repeat restenosis and occlusion remain common despite currently available technologies.

Endovascular stents: a review of their use in peripheral arterial disease

Technological advances in the past decade have shifted revascularization strategies from traditional open surgical approaches toward lower-morbidity percutaneous endovascular treatments for patients with lower extremity peripheral arterial disease (PAD). The continuing advances in stent design, more than any other advances, have fueled the growth of catheter-based procedures by improving the safety, durability, and predictability of percutaneous revascularization. Although the 2007 TransAtlantic Inter-Society Consensus (TASC) guidelines recommend endovascular therapy for type A and B aortoiliac and femoropopliteal lesions, recent developments in stent technology and increased experience of interventionists have suggested that a strategy of endovascular therapy first is appropriate in experienced hands for TASC type D lesions. The role of endovascular interventions is also expanding in the treatment of limb-threatening ischemia.

Current treatment methods for long occlusions of the femoropopliteal segment in patients with intermittent claudication: Minireview

Backround. Intermittent claudication is a classic symptom of peripheral arterial disease. It is mainly treated conservatively but if this fails, a form of revascularization is indicated. The revascularization in chronic occlusion of femoropopliteal region is currently performed by two basic methods: the standard method of surgical bypass and the newer miniinvasive alternative represented by the endovascular method. The treatment of patients with solely claudication and long occlusion of femoropopliteal region remains controversial. The aim of this minireview was to determine whether surgical bypass is still the best method of choice in a time of endovascular techniques.

METHODS

A MEDLINE search for original and review articles using key terms, intermittent claudication and long femoropopliteal oclusion.

RESULTS AND CONCLUSION

No ideal treatment for long occlusions of the femoropopliteal segment has been established to date. It is clear that the role of endovascular techniques in the treatment of SFA occlusions is increasing. It remains that, lower risk patients with claudication should be examined to assess the quality of veins suitable for revascularization and bypass should be selected as the first method of choice.

Prospective study of sarpogrelate hydrochloride on patients with arteriosclerosis obliterans

OBJECTIVE

To evaluate the effect of sarpogrelate for patients with atherosclerotic obliterans (ASO).

PATIENTS AND METHODS

Patients with ASO were randomly divided into sarpogrelate group (n = 92) and control group (n = 84). The patients in sarpogrelate group received sarpogrelate (100 mg, tid), whereas in control group aspirin (100 mg, qd) was administered orally. The patients were followed up monthly to observe any side effect of medication. Clinical manifestation, painless walking distance, Rutherford type and ankle brachial Index (ABI) were studied.

RESULTS

In comparison with control group, the severity of pain, Rutherford type 0 and 1 were improved with statistic significance. Incidence of patients with intermittent claudication decreased from 56.6% before treatment to 28.3% after treatment; the painless walking distance was prolonged (116.3 ± 72.3m vs. 243.5 ± 175.3m, P <0.001); ABI values were increased (0.74 ± 0.17 vs. 0.86 ± 0.18; p <0.001). No side effect of medication was observed.

CONCLUSION

Sarpogrelate has a therapeutic effect on patients with atherosclerotic obliterans.

Heparin-bonded, expanded polytetrafluoroethylene-lined stent graft in the treatment of femoropopliteal artery disease: 1-year results of the VIPER (Viabahn Endoprosthesis with Heparin Bioactive Surface in the Treatment of Superficial Femoral Artery Obstructive Disease) trial

PURPOSE

To evaluate the performance of a heparin-bonded, expanded polytetrafluoroethylene (ePTFE)-lined nitinol endoprosthesis in the treatment of long-segment occlusive disease of the femoropopliteal artery (FPA) and to identify factors associated with loss of patency.

MATERIALS AND METHODS

In a single-arm, prospective, 11-center study (VIPER [Gore Viabahn Endoprosthesis with Heparin Bioactive Surface in the Treatment of Superficial Femoral Artery Obstructive Disease] trial), 119 limbs (113 patients; 69 men; mean age, 67 y), including 88 with Rutherford category 3-5 disease and 72 with Inter-Society Consensus for the Management of Peripheral Arterial Disease (TASC II) C or D lesions of the FPA, underwent stent graft implantation. The mean lesion length was 19 cm; 56% of lesions were occlusions. Follow-up evaluations included color duplex ultrasonography in all patients, with patency defined as a peak systolic velocity ratio< 2.5.

RESULTS

At 12 months, Rutherford category and ankle-brachial index (ABI) were significantly improved (mean category improvement, 2.4; ABI increased from 0.6±0.2 to 0.9±0.19; P<.0001). Primary and secondary patency rates were 73% and 92%. The primary patency for devices oversized<20% at the proximal landing zone was 88%, whereas the primary patency for devices oversized by>20% was 70% (P = .047). Primary patency was not significantly affected by device diameter (5 vs 6 vs 7 mm) or lesion length (≤20 cm vs>20 cm). The 30-day major adverse event rate was 0.8%.

CONCLUSIONS

The heparin-bonded, ePTFE/nitinol stent graft provided clinical improvement and a primary patency rate of 73% at 1 year in the treatment of long-segment FPA disease. Careful sizing of the device relative to vessel landing zones is essential for achieving optimal outcomes.

Viabahn for femoropopliteal in-stent restenosis

BACKGROUND AND OBJECTIVES

In-stent restenosis in the femoropopliteal artery is common (20%-40%). Treatment of in-stent restenosis is challenged by poor patency rate. An ePTFE-covered stent-graft (Viabahn) is inert with a very small pore size that does not allow for significant tissue in-growth. Use of a Viabahn stent-graft may improve the patency rate in the treatment of in-stent restenosis.

DESIGN AND SETTING

A retrospective chart review of the use of Viabahn stent grafts implanted in patients with symptomatic femoropopliteal artery in-stent restenosis performed from January 2004 to December 2008.

PATIENTS AND METHODS

We measured the primary patency rate using duplex ultrasound at 1 year and 3 years. We also examined the rate of secondary patency, acute limb ischemia and amputation.

RESULTS

Twenty-seven cases with in-stent restenosis of the femoropopliteal artery treated by Viabahn stentgraft were identified. The average lesion length was 24.5 cm; 52% of the lesions were total occlusion and 37% had critical limb ischemia. The 1- and 3-year primary patency rates were 85.1% and 81.4%, respectively. The secondary patency rate was 96%. All recurrent in-stent restenoses were focal at the proximal and distal edges and none had stent fracture.

CONCLUSION

Our single center experience in a small number of patients showed a favorable patency of ePTFE-covered stent-graft for treatment of patients with in-stent restenosis in the femoropopliteal artery.

The BioStent: novel concept for a viable stent structure

OBJECTIVES

Percutaneous stenting of occluded peripheral vessels is a well-established technique in clinical practice. Unfortunately, the patency rates of small-caliber vessels after stenting remain unsatisfactory. The aim of the BioStent concept is to overcome in-stent restenosis by excluding the diseased vessel segment entirely from the blood stream, in addition to providing an intact endothelial cell layer.

DESIGN

The concept combines the principles of vascular tissue engineering with a self-expanding stent: casting of the stent within a cellularized fibrin gel structure, followed by bioreactor conditioning, allows complete integration of the stent within engineered tissue.

MATERIALS AND METHODS

Small-caliber BioStents (Ø=6 mm; n=4) were produced by casting a nitinol stent within a thin fibrin/vascular smooth muscle cell (vSMC) mixture, followed by luminal endothelial cell seeding, and conditioning of the BioStent within a bioreactor system. The potential remodeling of the fibrin component into tissue was analyzed using routine histological methods. Scanning electron microscopy was used to assess the luminal endothelial cell coverage following the conditioning phase and crimping of the stent.

RESULTS

The BioStent was shown to be noncytotoxic, with no significant effect on cell proliferation. Gross and microscopic analysis revealed complete integration of the nitinol component within a viable tissue structure. Hematoxylin and eosin staining revealed a homogenous distribution of vSMCs throughout the thickness of the BioStent, while a smooth, confluent luminal endothelial cell lining was evident and not significantly affected by the crimping/release process.

CONCLUSIONS

The BioStent concept is a platform technology offering a novel opportunity to generate a viable, self-expanding stent structure with a functional endothelial cell lining. This platform technology can be transferred to different applications depending on the luminal cell lining required.

Spontaneous rupture of superficial femoral artery repaired with endovascular stent-grafting with use of rendez-vous technique, followed by delayed infection

This is the case of a 72-year-old man with lower limb ischemia due to spontaneous rupture of nonaneurysmal superficial femoral artery that developed into thigh hematoma. After failure of a Fogarty revascularization, an emergency endovascular procedure was performed to restore the arterial continuity. A rendezvous procedure was performed with a double femoral and popliteal approach and two covered stent-grafts were deployed. Patient's clinical conditions immediately improved, but 4 months later the stent-grafts were surgically removed for infection and exteriorization. A femoropopliteal bypass was performed. After 1 year follow-up, the patient is in good clinical condition.

A Study on the Effects of Covered Stents on Tissue Prolapse

Polyvinyl alcohol (PVA) cryogel covered stents may reduce complications from thrombosis and restenosis by decreasing tissue prolapse. Finite element analysis was employed to evaluate the effects of PVA cryogel layers of varying thickness on tissue prolapse and artery wall stress for two common stent geometries and two vessel diameters. Additionally, several PVA cryogel covered stents were fabricated and imaged with an environmental scanning electron microscope. Finite element results showed that covered stents reduced tissue prolapse up to 13% and artery wall stress up to 29% with the size of the reduction depending on the stent geometry, vessel diameter, and PVA cryogel layer thickness. Environmental scanning electron microscope images of expanded covered stents showed the PVA cryogel to completely cover the area between struts without gaps or tears. Overall, this work provides both computational and experimental evidence for the use of PVA cryogels in covered stents.

Endovascular management of iliac vein rupture during percutaneous interventions for occlusive lesions

Iatrogenic Iliac vein rupture is a rare and potentially lethal complication. We present herein two different clinical scenarios of iatrogenic iliac vein rupture that resulted from performing percutaneous endoluminal interventions to treat symptomatic veno-occlusive lesions. The first case was due to the presence of surgical clips from the patient's previous gynecologic surgery, which caused iliac vein compression and eventually led to acute deep vein thrombosis. The second case resulted from central venous outflow obstruction ipsilateral to a lower extremity arteriovenous dialysis access site. Both Iliac vein ruptures were the result of percutaneous attempts to correct the outflow lesion (delayed in the first case and acute in the second case). Hemorrhage was successfully controlled in both cases using a self-expandable Viabahn (W. L. Gore and Associates, Flagstaff, AZ) covered stent while maintaining vessel patency and resolving symptoms related to veno-occlusive disease.

Excimer laser with adjunctive balloon angioplasty and heparin-coated self-expanding stent grafts for the treatment of femoropopliteal artery in-stent restenosis: twelve-month results from the SALVAGE study

OBJECTIVES

The aim of the study is to evaluate the safety and effectiveness of treating femoropopliteal in-stent restenosis (ISR) with debulking with excimer laser followed by implantation of a VIABAHN endoprosthesis.

BACKGROUND

The optimal treatment strategy for femoropopliteal ISR is unclear.

METHODS

The SALVAGE study is a multicenter prospective registry involving nine US centers. Patients with femoropopliteal ISR with moderate to severe intermittent claudication or critical limb ischemia (Rutherford categories 2-5) and an ankle-brachial index (ABI) =0.8 were treated with excimer laser and the VIABAHN endoprosthesis. The primary efficacy endpoint is primary patency at 12 months as measured by duplex ultrasonography. The primary safety endpoint is the major adverse event (MAE) rate at 30 days.

RESULTS

Twenty-seven patients were enrolled. The mean lesion length was 20.7 ± 10.3 cm. The majority of lesions were TASC (TASC I) C and D (81.4%). All lesions were pretreated with excimer laser and percutaneous transluminal angioplasty (PTA) prior to VIABAHN implantation. Technical success was achieved in 100% of cases. There were no MAE at 30 days. Primary patency at 12 months was 48%. The ankle brachial index increased from 0.58 ± 0.24 at baseline to 0.90 ± 0.17 at 12 months. There was improvement in all quality-of-life parameters. The 12-month TLR rate was 17.4%.

CONCLUSIONS

The strategy of excimer laser atherectomy and PTA followed by implantation of a self-expanding stent graft for the treatment of femoropopliteal ISR is safe and associated with high procedural success. Primary patency rate at 12-months was suboptimal; however, the TLR rate was low.

Use of covered stents in the central vein: a feasibility study in a canine model

PURPOSE

To evaluate the feasibility of using covered stents vs. bare stents in a model of central vein stenosis with an arteriovenous graft created to mimic the conditions in hemodialysis patients.

METHODS

In 7 mongrel dogs, an expanded polytetrafluoroethylene-covered nitinol stent was placed in one common iliac vein and a bare stent was placed in the contralateral vein. Arteriovenous grafts were created bilaterally between the common femoral artery and vein to induce endothelial damage. Neointima formation in the covered stents was compared to the bare stents at 12 weeks using microscopy and histochemical staining.

RESULTS

Two dogs were excluded due to thrombosis and infection of the arteriovenous grafts, but all stents in the remaining 5 dogs were patent. Smooth, complete neointimal coverage was observed on the inner surface of all the covered stents without intraluminal thrombus. In contrast, incomplete neointimal coverage was seen in all bare stents, with small focal thrombi adhering to the neointima on 3 bare stents. Focal nodular neointimal hyperplasia with denudation of the endothelium was observed in only 2 bare stents. Mean neointimal thickening was significantly greater in the covered stents. Eccentric neointimal thickening was observed at the inflow and outflow segments of both types of stents.

CONCLUSION

Covered stents are technically feasible for the treatment of central vein stenosis, and they demonstrate complete, smooth neointimal coverage in normal central veins, but they also display greater neointimal thickening than bare stents.

Endovascular treatment of femoral-popliteal disease

Available and improved options for the treatment of femoral-popliteal disease have increased over the last decade. Even though most patients suffering from claudication due to femoral-popliteal disease are treated with aggressive medical and noninvasive methods, patients with limb-threatening disease and severely lifestyle-limiting symptoms are treated with invasive treatments, which include endovascular treatment options. Unfortunately, the unique forces involved in this vascular segment have challenged the long-term patency and clinical effectiveness of these treatments. The purpose of this brief review is to discuss treatment strategies and options for patients with femoral-popliteal disease. Included in this discussion will be the review of data from recent published studies and late-breaking trials as it pertains to certain treatment strategies.

Current approach to the diagnosis and treatment of femoral-popliteal arterial disease. A systematic review

Peripheral arterial disease (PAD) is a common manifestation of atherosclerosis affecting 5 million adults in the United States, with an age-adjusted prevalence of 4% to 15% and increasing up to 30% with age and the presence of cardiovascular risk factors. In this article we focus on lower extremity PAD and specifically on the superficial femoral and proximal popliteal artery (SFPA), which are the most common anatomic locations of lower extremity atherosclerosis. We summarize current evidence and perform a systematic review on the diagnostic evaluation as well as the medical, endovascular and surgical management of SFPA disease.

Results With Viabahn-Assisted Subintimal Recanalization for TASC C and TASC D Superficial Femoral Artery Occlusive Disease

Objectives: Many investigators including TransAtlantic Inter-Society Consensus (TASC) recommend against primary endovascular treatment for severe (TASC C and D) superficial femoral artery (SFA) disease. Vein bypass is preferable but may not be appropriate due to comorbidities or lack of suitable vein. This study reviews our results with Viabahn stent graft-assisted subintimal recanalization (VASIR) for TASC C and D SFA atherosclerosis. Methods: In all, 13 males and 14 females, mean age 72 ± 11 years underwent 28 VASIR for severe (TASC C 8 of 28, TASC D 20 of 28, and 5 of 28 no continuous infrapopliteal runoff artery) SFA disease. Indications were claudication (14 of 28 limbs), ischemic rest pain (6 of 28), and tissue loss (8 of 28). Viabahn stent graft-assisted subintimal recanalization was chosen instead of bypass due to comorbidities or lack of vein. Patients received aspirin and, if not already taking warfarin, they also received clopidogrel. Patients were examined with Ankle-brachial Index (ABI) and duplex scan at 1 month, then every 3 months after VASIR. Results Viabahn stent graft-assisted subintimal recanalization was technically successful in all. Ankle-brachial Index averaged 0.47 ± 0.17 preprocedure, 0.89 ± 0.20 postprocedure, and increased by 0.15 or more in every case. Median follow-up is 20 months. There were 3 perioperative (<30 days) and 7 later failures including revision prior to any thrombosis. One patient required amputation. Four have died, 2 with patent grafts, none from causes related to VASIR, all more than 30 days post-VASIR. Estimated 1-year primary and secondary patency were 70% ± 11% and 73% ± 10%. Failure was not significantly associated with indications, comorbidities, or runoff status. There was a clear distinction between patients with early failure and the rest of the patients. None of the 8 patients with failure in the first 8 months after surgery has a patent graft. However, of 17 grafts primarily patent at 8 months, only 2 have failed (1 thrombosed and 1 required preemptive balloon angioplasty). There was a strong trend toward better patency with 6 and 7 mm diameter compared to 5 mm diameter stent grafts. Furthermore, although warfarin was not prescribed as part of the protocol, no patient taking warfarin before and who resumed warfarin after VASIR (n = 4) suffered failure. Conclusions: Despite significant early failures, we found VASIR to be durable in those who did not have early failure. Viabahn stent graft-assisted subintimal recanalization is an acceptable alternative to vein bypass in selected patients with severe SFA disease. Smaller arterial or stent graft diameter may be associated with poorer results. Warfarin may be valuable to reduce the risk of failure after VASIR.

[Evolution of stents for the treatment of femoral artery lesions]

Endovascular treatment and stent implantation in the superficial femoral artery have been proposed for over 20 years. However, the first experiments with stainless stents were relatively disappointing. The first improvement consisted in the introduction of nitinol self-expanding stents. This technology allowed an initial improvement of clinical performances, but the first generation of nitinol stents demonstrated a relatively high rate of fractures. Better knowledge of the femoral artery biomechanics and advances in technology allowed to propose a second generation of nitinol stents with improved flexibility, which decreased the rates of fracture. In-stent restenosis related to neointimal hyperplasia has also led to the development of new concepts to improve patency rates after stenting of the femoral artery: drug-eluting stents (coated-stents), biodegradable stents, and covered stents. These technologies will help to treat more complex lesions of the femoral artery in the future, with comparable results to those obtained with femoropopliteal bypasses, but we are still waiting for results of ongoing studies.

Outcomes following treatment of femoropopliteal in-stent restenosis: a single center experience

OBJECTIVES

The aim of this study is to describe a single-center experience with endovascular treatment of femoropopliteal in-stent restenosis (ISR).

BACKGROUND

Femoropopliteal artery stenting is associated with a significant risk of ISR. Data are limited on the optimal treatment strategy and associated outcomes.

METHODS

A single institution retrospective chart review study was performed for patients who underwent endovascular treatment of femoropopliteal ISR from January 2006 to October 2008. Clinical and procedural characteristics, angiographic findings, and 12-month primary and secondary patency rates were analyzed. Univariate analysis was performed to identify predictors of 12-month primary patency.

RESULTS

Twenty-two limbs were treated in 20 patients during the study period. Procedural success was achieved in 21 limbs (95.5%). Laser, balloon angioplasty, and excisional atherectomy were the primary therapy in 52.4%, 33.3%, and 14.3% of the cases, respectively. Adjunctive balloon angioplasty was performed after laser and excisional atherectomy in all cases. The mean length of ISR was 13.2 ± 11.3 cm with a significant proportion of cases (40.9%) having Type IV pattern of ISR. At 12 months, primary and combined primary-assisted and secondary patency rates were 47.6 and 61.9%, respectively. Of the 11 limbs that did not have secondary patency, 6 had mild or no symptoms, and, therefore, repeat intervention was not performed. There was one transmetatarsal amputation during the 12-month follow-up period. In this study, there was no significant predictor of 12-month primary patency.

CONCLUSIONS

Treatment of ISR remains challenging with significant risk of recurrent restenosis. Further research is required to improve long-term patency.

In vitro hemocompatibility of thin film nitinol in stenotic flow conditions

Because of its low profile and biologically inert behavior, thin film nitinol (TFN) is ideally suited for use in construction of endovascular devices. We have developed a surface treatment for TFN designed to minimize platelet adhesion by creating a superhydrophilic surface. The hemocompatibility of expanded polytetrafluorethylene (ePTFE), untreated thin film nitinol (UTFN), and a surface treated superhydrophilic thin film nitinol (STFN) was compared using an in vitro circulation model with whole blood under flow conditions simulating a moderate arterial stenosis. Scanning electron microscopy analysis showed increased thrombus on ePTFE as compared to UTFN or STFN. Total blood product deposition was 6.3 ± 0.8 mg/cm(2) for ePTFE, 4.5 ± 2.3 mg/cm(2) for UTFN, and 2.9 ± 0.4 mg/cm(2) for STFN (n = 12, p < 0.01). ELISA assay for fibrin showed 326 ± 42 μg/cm(2) for ePTFE, 45.6 ± 7.4 μg/cm(2) for UTFN, and 194 ± 25 μg/cm(2) for STFN (n = 12, p < 0.01). Platelet deposition measured by fluorescent intensity was 79,000 20,000 AU/mm(2) for ePTFE, 810 ± 190 AU/mm(2) for UTFN, and 1600 ± 25 AU/mm(2) for STFN (n = 10, p < 0.01). Mass spectrometry demonstrated a larger number of proteins on ePTFE as compared to either thin film. UTFN and STFN appear to attract significantly less thrombus than ePTFE. Given TFN's low profile and our previously demonstrated ability to place TFN covered stents in vivo, it is an excellent candidate for use in next-generation endovascular stents grafts.

Four-year randomized prospective comparison of percutaneous ePTFE/nitinol self-expanding stent graft versus prosthetic femoral-popliteal bypass in the treatment of superficial femoral artery occlusive disease

BACKGROUND

This is a randomized prospective study comparing the treatment of superficial femoral artery occlusive disease percutaneously with an expanded polytetrafluoroethylene (ePTFE)/nitinol self-expanding stent graft (stent graft) versus surgical femoral to above-knee popliteal artery bypass with synthetic graft material.

METHODS

One hundred limbs in 86 patients with superficial femoral artery occlusive disease were evaluated from March 2004 to May 2005. Patient symptoms included both claudication and limb threatening ischemia with or without tissue loss. Trans-Atlantic InterSociety Consensus (TASC II) A (n = 18), B (n = 56), C (n = 11), and D (n = 15) lesions were included. Patients were randomized prospectively into one of two treatment groups; a percutaneous treatment group (group A; n = 50) with angioplasty and placement of one or more stent grafts, or a surgical treatment group (group B; n = 50) with a femoral to above-knee popliteal artery bypass using synthetic conduit (Dacron or ePTFE). Patients were followed for 48 months. Follow-up evaluation included clinical assessment, physical examination, ankle-brachial indices, and color flow duplex sonography at 3, 6, 9, 12, 18, 24, 36, and 48 months.

RESULTS

Mean total lesion length of the treated arterial segment in the stent graft group was 25.6 cm (SD = 15 cm). The stent graft group demonstrated a primary patency of 72%, 63%, 63%, and 59% with a secondary patency of 83%, 74%, 74%, and 74% at 12, 24, 36, and 48 months, respectively. The surgical femoral-popliteal group demonstrated a primary patency of 76%, 63%, 63%, and 58% with a secondary patency of 86%, 76%, 76%, and 71% at 12, 24, 36, and 48 months, respectively. No statistical difference was found between the two groups with respect to primary (P = .807) or secondary (P = .891) patency.

CONCLUSION

Management of superficial femoral artery occlusive disease with percutaneous stent grafts exhibits similar primary patency at 4-year (48 month) follow up when compared with conventional femoral-popliteal artery bypass grafting with synthetic conduit. This treatment method may offer an alternative to treatment of the superficial femoral artery segment for revascularization when prosthetic bypass is being considered or when autologous conduit is unavailable.