Routine stent implantation vs. percutaneous transluminal angioplasty in femoropopliteal artery disease: a meta-analysis of randomized controlled trials

Network Meta-analysis of Randomised Controlled Trials Comparing the Outcomes of Different Endovascular Revascularisation Treatments for Infra-inguinal Peripheral Arterial Disease Causing Chronic Limb Threatening Ischaemia

OBJECTIVE

The aim of this study was to compare the efficacy of different endovascular revascularisation procedures for treating chronic limb threatening ischaemia (CLTI) using network meta-analysis (NMA).

DATA SOURCES

The databases PubMed and Cochrane Central Register for Controlled Trials were searched on 14 March 2023.

REVIEW METHODS

A NMA of randomised controlled trials (RCTs) reporting the efficacy of different endovascular revascularisation techniques for treating CLTI was performed according to PRISMA guidelines. The primary and secondary outcomes were major amputation and death, respectively. Random effects models were developed and the results were presented using surface under the cumulative ranking curve plots and forest plots. A p value of ≤ .050 was considered statistically significant. The Cochrane collaborative tool was used to assess risk of bias.

RESULTS

A total of 2 655 participants of whom 94.8% had CLTI were included. Eleven trials compared plain balloon angioplasty (PBA) vs. drug coated balloon (DCB) angioplasty (n = 1 771), five trials compared bare metal stent (BMS) vs. drug coated stent (DCS) (n = 466), three trials compared atherectomy vs. DCB (n = 194), two trials compared PBA vs. BMS (n = 70), one trial compared PBA vs. atherectomy (n = 50), and one trial compared BMS vs. DCB (n = 104). None of the revascularisation strategies significantly reduced the risk of major amputation or death compared with PBA. Using the network estimates, GRADE certainty of evidence for improvement in major amputation outcomes for DCB was moderate, for atherectomy and BMS was low, and for DCS was very low compared with PBA. Risk of bias was low in 16 trials, of some concerns in six trials, and high in one trial, respectively.

CONCLUSION

There is no current evidence from RCTs to reliably conclude that BMS, DCB, DCS, or atherectomy are superior to PBA in preventing major amputation and death in patients with CLTI. Larger comparative RCTs are needed to identify the best endovascular revascularisation strategy.

Comparison of the Pre-Established and Finally Selected Treatment Strategies for Endovascular Treatment in Femoropopliteal Artery Lesions

This study aimed to compare lower limb events associated with preplanned and finally selected treatment strategies-the validity and usefulness of the physician-chosen strategy were verified.We examined the data of 1003 patients in the registry of multicenter endovascular treatment for superficial femoral and popliteal artery disease study and prospectively enrolled patients who underwent endovascular treatment (EVT) of the femoropopliteal (FP) artery between February 2017 and June 2018 from 67 Japanese institutes. The outcome measures were major adverse limb events (MALE) and target vessel revascularization.The EVT strategies were classified into balloon angioplasty-alone (37.3%), primary stenting (26.7%), and provisional stenting (36.0%) groups. In the initial strategy analysis for the balloon angioplasty-alone, primary stenting, and provisional stenting groups, two-year rates of freedom from MALE (95% confidence interval) were 0.680 (0.620-0.732), 0.754 (0.688-0.808), and 0.798 (0.746-0.840), respectively. Additionally, the rate of MALE was significantly higher among patients in the balloon angioplasty-alone group than among those in the primary or provisional stenting groups in the initial strategy analysis (P = 0.007). Changes in treatment strategy were more frequent in the primary stenting group than in the other groups. Furthermore, the rate of MALE did not significantly differ among the three groups in the final strategy analysis (P = 0.56).Limb outcomes for the final applied strategy did not differ among the three strategies. Additionally, the physician's selection bias was mostly appropriate in the EVT of the FP artery.

Usage of rotational atherectomy and drug-coated balloon angioplasty for isolated popliteal artery lesions: two-year results of a retrospective study

OBJECTIVES

In this study, perioperative properties and early and mid-term clinical outcomes of endovascular revascularization with a combined usage of rotational atherectomy (RA) and drug-coated balloon angioplasty (DCB) angioplasty for isolated popliteal artery lesion were reported.

METHODS

A total of 28 patients with isolated popliteal artery stenosis who underwent combined RA and DCB angioplasty between December 2018 and September 2022 were analyzed retrospectively. Temren atherectomy system (Invamed, Ankara, Turkey) and Extender paclitaxel-coated drug-coated balloon catheter (Invamed, Ankara, Turkey) were used in all cases. The main outcome was primary patency; secondary outcomes were technical success, freedom from amputation, and mortality.

RESULTS

The mean age of patients was 64.2 ± 9.1 years and the majority of the patients were male (n = 20; 71.4%). Types of the lesions were total occlusion in 24 limbs and critical stenosis in 4 limbs. The mean total occlusion length was 65.2 ± 14.2 mm. Flow-limiting dissection was seen in lesions of 2 patients (7.1%) and treated with prolonged balloon dilatation without bail-out stenting requirement. Technical success defined as an adequate vascular lumen (less than 30% stenosis) was achieved in 26 (92.8%) with a mean follow-up of 17.2 ± 8.2 months. The mean primary patency rates at 12 months and 24 months were 92.3% ± 3.2 and 81.2% ± 3.2, respectively. Complications included 1 distal embolization following RA, 2 flow-limiting dissections, and 3 puncture site hematomas.

CONCLUSIONS

Endovascular procedures using combined RA and DCB angioplasty seem to be effective alternative treatment modalities for the treatment of popliteal artery lesions with high rates of primary patency and freedom from TLR.

Endovascular Revascularization and Outcomes of Critical Limb-Threatening Ischemia in Trinidad and Tobago: The EVENT Pilot Study-Challenges in a Limited-Resource, Caribbean Setting

INTRODUCTION

This retrospective study investigated major adverse limb events (MALE) and mortality outcomes in critical limb-threatening ischemia (CLTI) patients with tissue loss after an endovascular revascularization-first (EVR-1st) strategy.

METHODS

MALE and mortality were assessed in 157 consecutive patients with CLTI and tissue loss from June 2019 to June 2022 at the Eric Williams Medical Sciences Complex, Trinidad and Tobago.

RESULTS

157 patients underwent the EVR-1st strategy, of whom 20 were pivoted to immediate surgical revascularization (SR). Of the remaining 137 patients, successful EVR was achieved in 112, giving a procedural success of 82% and an all-comer overall success of 71%. The mortality and MALE rates were 2.7% and 8.9% at 2 years, respectively. Males and patients with previous major amputations were at significantly higher risk for MALE (p values of 0.016 and 0.018, respectively). There was a statistically significant difference in successful EVR for both Rutherford-Baker (RB) 5 (minor) and RB 6 (major) classifications: 63 (56%) vs. 5 (20%) and 49 (44%) vs. 20 (80%), both with a p value of 0.01. There were no differences in successful EVR amongst Wound, Ischemia, Foot Infection (WIfI) clinical stages. There were no differences in successful EVR amongst the Trans-Atlantic Inter-Society Consensus (TASC II) classifications.

CONCLUSIONS

This study may prove clinically informative and applicable for an EVR-1st management strategy for high-risk patients with CLTI in a limited-resource, Caribbean setting.

TRIAL REGISTRATION NUMBER

NCT05547022 (retrospectively registered).

Safety of paclitaxel-coated devices in the femoropopliteal arteries: A systematic review and meta-analysis

Background

Clinical benefit of paclitaxel-coated devices for patients with peripheral arterial disease has been confirmed in randomized controlled trials (RCTs). A meta-analysis published in 2018 identified late mortality risk over a long follow-up period due to use of paclitaxel-coated devices in the femoropopliteal arteries, which caused enormous controversy and debates globally. This study aims to further evaluate the safety of paclitaxel-coated devices by incorporating the most recently published data.

Methods

We searched for candidate studies in PubMed (MEDLINE), Scopus, EMBASE (Ovid) online databases, government web archives and international cardiovascular conferences. Safety endpoints of interest included all-cause mortality rates at one, two and five years and the risk ratio (RR) was used as the summary measure. The primary analysis was performed using random-effects models to account for potential clinical heterogeneity.

Findings

Thirty-nine RCTs including 9164 patients were identified. At one year, the random-effects model yielded a pooled RR of 1.06 (95% CI [0.87, 1.29]) indicating no difference in short-term all-cause deaths between the paclitaxel and control groups (crude mortality, 4.3%, 214/5025 versus 4.5%, 177/3965). Two-year mortality was reported in 26 RCTs with 382 deaths out of 3788 patients (10.1%) in the paclitaxel arm and 299 out of 2955 patients (10.1%) in the control arm and no association was found between increased risk of death and usage of paclitaxel-coated devices (RR 1.08, 95% CI [0.93, 1.25]). Eight RCTs recorded all-cause deaths up to five years and a pooled RR of 1.18 (95% CI [0.92, 1.51]) demonstrated no late mortality risk due to use of paclitaxel-coated devices (crude mortality, paclitaxel 18.2%, 247/1360 versus control 15.2%, 122/805).

Conclusions

We found no significant difference in either short- or long-term all-cause mortalities between patients receiving paclitaxel-coated and uncoated devices. Further research on the longer-term safety of paclitaxel usage (e.g., 8- or 10-year) is warranted.

Registration

PROSPERO, CRD42021246291.

Bailout stenting in femoropopliteal arterial segment

Background: Disabling peripheral arterial disease (PAD) of femoropopliteal segment is usually treated with percutaneous balloon dilatation, and when this is not successful, stent is placed. Long-term patency of stent is often compromised due to in-stent restenosis (ISR). We aimed to identify factors associated with bailout stenting, and to recognise risk factors for ISR in procedures without paclitaxel application. Patients and methods: We analysed 592 consecutive successful femoropopliteal interventions performed in patients with either disabling intermittent claudication or chronic critical limb ischemia (CLI). In patients with stent implantation, clinical and ultrasound (US) examination were performed one year after the intervention to establish the presence of ISR, defined as >50% stenosis on US imaging. Results: Bailout stenting was required in 133 (22.5%) procedures. Patients with stent placement were younger (70±10 vs 72±11 years, p=0.007) and less often presented with CLI (29.3% vs 40.5%, p=0.019). They more often reported smoking (63.2% vs 49.2%, p=0.005), less often had diabetes mellitus (35.3% vs 47.5%, p=0.013) and arterial hypertension (82.0% vs 90.8%; p=0.004). Stenting was also dependent on lesion complexity (TASC II C>B>A; p<0.001). Subgroup analysis of 110 procedures with bare metal stent (BMS) placement performed in 107 patients revealed ISR in 46.4% of stents, in half of cases it was symptomatic. Neither clinical nor lesion characteristics proved to differ between the group of procedures with ISR and group of procedures without ISR. Conclusions: Factors associated with bailout stenting were age, diabetes mellitus, arterial hypertension, smoking, clinical picture of PAD and complexity of treated lesions. We did not find any risk factors influencing development of ISR in BMS.

Three-Year Clinical Outcomes of the Innova™ Self-Expanding Nitinol Stent for the Treatment of Femoropopliteal Lesions

PURPOSE

To report the 3-year results of Innova™ stent implantation for the treatment of femoropopliteal (FP) lesions in a real-world setting.

METHODS

This single-arm, retrospective, multicenter clinical study analyzed 481 lesions from 453 consecutive patients with symptomatic peripheral artery diseases (Rutherford category 1-6) who underwent endovascular therapy with implantation of Innova™ self-expanding nitinol stent for FP lesions. The primary outcome measure was the 3-year restenosis rate based on doppler-ultrasound or angiographic criteria. The secondary outcome measures included the rates of 3-year major amputation and major adverse limb events.

RESULTS

Restenosis following Innova™ implantation was found in 61% of the cases at 3 years. At the end of 3 years, the rates of major amputations and major adverse limb events were 3 and 31%, respectively. In cases free from restenosis at 1 year, no predictive factors for restenosis at 3 years could be determined.

CONCLUSION

The present study demonstrated mid-term clinical outcomes after Innova™ stent implantation for the treatment of FP lesions in a real-world population. The Innova™ stent demonstrated acceptable clinical outcomes in a real-world setting.

An Update on Drug-eluting Technology in Peripheral Arteries to Treat Peripheral Arterial Disease

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Three-Year Efficacy and Safety of the Misago Peripheral Stent for Superficial Femoral Artery Disease: Final Results from the OSPREY Trial

PURPOSE

This study evaluated the long-term outcomes of the Misago peripheral stent trial (Terumo) for atherosclerotic lesions in the superficial femoral artery (SFA) in patients with claudication.

MATERIALS AND METHODS

This was a prospective multicenter, single-arm, clinical trial of primary stent placement for de novo cases of SFA disease conducted in the United States and Asia. The primary endpoint was freedom from clinically driven target lesion revascularization (CD-TLR) at 36 months. Secondary outcomes were ankle-brachial index (ABI), Rutherford score, Walking Impairment Questionnaire (WIQ), a quality of life survey, and rate of device fracture.

RESULTS

A total of 276 patients (64.4% male; mean age, 69.3 ± 10.1 years) were enrolled. Freedom from CD-TLR was 78.5% (95% confidence interval [CI], 73.0%-83.0%) at 24 months and 75.4% (95% CI, 69.6%-80.2%) at 36 months. Baseline ABI was 0.7 ± 0.1 and 0.98 ± 0.20 (P < .001) at 30 days after the procedure. Baseline Rutherford score was 3.6 ± 0.6 and 1.6 ± 1.0 30 at 30 days after the procedure (P < .001). Mean (and changed) ABI and Rutherford score at 36 months compared to day 30 after the procedure were, respectively, 0.91 (-0.1 ± 0.2) and 1.5 (-0.2 ± 1.1). WIQ score at baseline was 21.49 ± 26.30 and 50.51 ± 38.49 at 30 days after the procedure ( P < .001). The mean WIQ score at 2 years was 46.65 ± 37.31 (P = .12). Stent fracture rate at 36 months was 2.0% (4 of 202 patients).

CONCLUSIONS

OSPREY (Occlusive-Stenotic Peripheral Artery Revascularization Study) 36-month data demonstrated persistent freedom from CD-TLR and sustained improvement in ABI and Rutherford score with primary stent placement for SFA lesions.

One-Year Late Lumen Loss between A Polymer-Coated Paclitaxel-Eluting Stent (Eluvia) and a Polymer-Free Paclitaxel-Coated Stent (Zilver PTX) for Femoropopliteal Disease

Aim: Paclitaxel-eluting stents' (Eluvia and Zilver PTX) effectiveness has been recently reported for femoropopliteeal (FP) lesions. However, there is no evaluation of one-year late lumen loss (LLL). Therefore, we evaluated one-year LLL after implantation with Eluvia or Zilver PTX.

Methods: This was a multicenter, prospective study. Patients who had symptomatic de novo lesions in the native FP artery were enrolled. The primary endpoint was one-year angiographic LLL, and the secondary endpoints were binary restenosis and target lesion revascularization (TLR) at one year.

Results: From December 2015 to December 2016, 48 patients (Eluvia, 36 patients; Zilver PTX, 12 patients) were enrolled. No significant difference was found in baseline and lesion characteristics between both groups. One-year, LLL was significantly lower in the Eluvia group (0.60 {plus minus}0.80 mm) than in the Zilver PTX group (1.74 {plus minus}0.89 mm) (P = 0.0003). Negative LLL was observed only in the Eluvia group (0% vs. 23%, p = 0.096). The binary restenosis rate was significantly lower than in the Zilver PTX group (0% vs. 16.7%, P = 0.012). The one-year TLR in the Eluvia group tended to be lower (0% vs. 8.3%, P = 0.08). Stent thrombosis was not observed in either group.

Conclusion: One-year LLL in the Eluvia group was significantly lower than that in the Zilver PTX group for FP lesions.

Long-Term In Vivo Oxygen Sensors for Peripheral Artery Disease Monitoring

Tracking of tissue oxygenation around chronic foot wounds may help direct therapy decisions in patients with peripheral artery disease (PAD). Novel sensing technology to enable such monitoring was tested over 9 months in a Sinclair mini-pig model. No adverse events were observed over the entire study period. Systemic and acute hypoxia challenges were detected during each measurement period by the microsensors. The median time to locate the sensor signal was 13 s. Lumee Oxygen microsensors appear safe for long-term repeated oxygen measurements over 9 months.

Primary stenting for femoropopliteal peripheral arterial disease: analysis up to 24 months

Background

Primary stenting is a well-established treatment option for femoropopliteal arterial obstructive disease. There is a shortage of Brazilian studies of the subject.

Objectives

To evaluate short and mid-term clinical and radiological outcomes in patients classified as Rutherford 3-6 and treated with stenting of femoropopliteal lesions.

Methods

Analysis based on a prospectively populated database of patients treated from July 2012 to July 2015. The primary endpoint was primary patency. Secondary endpoints were clinical and ankle/brachial index changes. Target Vessel Revascularization, limb salvage rate and death, within a 24-month follow-up period.

Results

64 patients were enrolled, including 61 TASC II A / B lesions (95%). The primary patency rates at 6, 12, and 24 months were 95.2%, 79.1% and 57.9%, respectively. Cox regression analysis revealed lower patency rates in patients with occlusive disease (hazard ratio [HR], 6.64; 95% confidence interval [CI], 1.52-28,99, p = 0.02), as well as patency loss about 6 times higher in TASC B than in TASC A patients ([HR], 5.95, 95% CI, 1.67-21.3, p = 0.0061). At 12 months, 90.38% of the patients remained asymptomatic. The limb salvage rate at 24 months was 94.3% (95% CI, 87.9-100%). Freedom from TVR at 24 months was 90.5% (95% CI 82.8-98.9%).

Conclusions

Results of primary patency were compatible with international studies, despite the more advanced stage of the vascular disease observed in our group. Occlusive disease and complex lesions were both associated with worse outcomes.

Clinical outcomes of balloon angioplasty alone versus nitinol stent implantation in patients with small femoropopliteal artery disease: Observations from the Retrospective Multicenter Analysis for Femoropopliteal Stenting (REAL-FP)

OBJECTIVES

We sought to assess whether balloon angioplasty (BA) alone for small femoropopliteal disease improved the outcome following endovascular therapy as compared with stent implantation.

BACKGROUND

The optimal strategy of endovascular therapy for small vessel arteries in femoropopliteal disease remains unclear.

METHODS

We performed a multicenter retrospective analysis of 337 consecutive patients (371 limbs) with femoropopliteal arteries 4.0 mm or less in diameter and 150 mm or less in length.

RESULTS

Cumulative 3-year incidence of primary patency was significantly higher in the BA group than in the stent group (53.8% vs. 34.2%, P = 0.002). While assisted-primary patency and freedom from any major adverse limb events were also significantly higher in the BA group than in the stent group (70.9% vs. 44.2%, P < 0.001 and 60.6% vs. 36.4%, P = 0.001, respectively), secondary patency did not significantly differ between the two groups (86.9% vs. 86.9%, P = 0.67). Predictors of restenosis were diabetes mellitus (hazard ratio [HR], 1.61; 95% confidence interval [CI], 1.14-2.31; P = 0.01), no administration of cilostazol (HR, 1.50; 95% CI, 1.07-2.13; P = 0.02), stent implantation (HR, 1.68; 95% CI, 1.15-2.41; P = 0.01), and lesion length >75.0 mm(HR, 2.09; 95% CI, 1.50-2.92; P < 0.001).

CONCLUSIONS

Lesions in small (<4.0 mm diameter) FP vessels demonstrated better primary patency at 3 years when successfully treated with balloon angioplasty alone as opposed to routine or bailout stenting. This difference was especially pronounced for lesions 75 to 150 mm in length.

Is Common Femoral Artery Stenosis Still a Surgical Disease?

Surgical endarterectomy has long been the standard approach for treating atherosclerotic stenosis in the common femoral artery. Its major advantage is the associated long-term patency, which approaches 95% at 5 years. Nevertheless, recent studies have suggested that percutaneous treatment may be a valid alternative to surgery.

Femoropopliteal Artery Stent Thrombosis: Report From the Excellence in Peripheral Artery Disease Registry

BACKGROUND

There are limited data on femoropopliteal artery stent thrombosis (ST), which is a serious adverse outcome of peripheral artery interventions.

METHODS AND RESULTS

Index procedures resulting in femoropopliteal ST were compared with stent procedures without subsequent ST in the Excellence in Peripheral Artery Disease registry. The study data had a total of 724 cases of stent procedures and 604 unique patients. Femoropopliteal ST occurred in 26 of 604 patients (4.3%) over a median follow-up of 6 months post procedure. ST was more likely to occur in men (96.3% versus 82.2%; P=0.026) and to have an initial intervention for chronic total occlusions (88.5% versus 64.0%; P=0.01). There was no significant difference in ST between drug-coated and bare-metal stents (4.4% versus 3.4%; P=0.55), but the rate of ST was significantly higher with self-expanding covered stent grafts compared with bare-metal stents (10.6% versus 3.4%; P=0.02). ST was significantly associated with an increased risk of 12-month major adverse limb events (hazard ratio, 4.99; 95% confidence interval, 2.31-10.77; P<0.001) compared with no ST. On multivariate analysis, treatment of chronic total occlusion lesions (odds ratio, 3.46; 95% confidence interval, 0.98-12.20; P=0.05) and in-stent restenosis lesions (odds ratio, 5.30; 95% confidence interval, 1.83-15.32; P=0.002) were independently associated with an increased risk of ST.

CONCLUSIONS

In a multicenter peripheral interventional registry, femoropopliteal ST occurred in 4.3% of patients who underwent stent procedures, and it was associated with treatment of chronic total occlusions and in-stent restenosis lesions, and had higher 12-month major adverse limb events.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT01904851.

Are drug-coated balloons cost effective for femoropopliteal occlusive disease? A comparison of bare metal stents and uncoated balloons

Aim: To perform a cost–effectiveness analysis to help hospital decision-makers with regard to the use of drug-coated balloons compared with bare metal stents and uncoated balloons for femoropopliteal occlusive disease. Methods: Clinical outcomes were extracted from the results of meta-analyses already published, and cost units are those used in the Quebec healthcare network. The literature review was limited to the last four years to obtain the most recent data. The cost–effectiveness analysis was based on a 2-year perspective, and risk factors of reintervention were considered. Results: The cost–effectiveness analysis indicated that drug-coated balloons were generally more efficient than bare metal stents, particularly for patients with higher risk of reintervention (up to CAD$1686 per patient TASC II C or D). Compared with uncoated balloons, results indicated that drug-coated balloons were more efficient if the reintervention rate associated with uncoated balloons is very high and for patients with higher risk of reintervention (up to CAD$3301 per patient). Conclusion: The higher a patient's risk of reintervention, the higher the savings associated with the use of a drug-coated balloon will be. For patients at lower risk, the uncoated balloon strategy is still recommended as a first choice for endovascular intervention.

Systematic Review and Meta-analysis of Randomized Controlled Trials of Paclitaxel-Coated Balloon Angioplasty in the Femoropopliteal Arteries: Role of Paclitaxel Dose and Bioavailability

PURPOSE

To provide a qualitative analysis and quantitative synthesis of randomized controlled trials (RCTs) investigating paclitaxel-coated balloons (PCBs) in the femoropopliteal artery.

METHODS

PubMed, EMBASE, AMED, Scopus, CENTRAL, online content, and abstracts from international meetings were last screened in April 2015 for eligible RCTs using the PRISMA selection process. Risk of bias was assessed using the Cochrane Collaboration's tool, and quality of evidence was evaluated with the GRADE system. Outcome measures included late lumen loss (LLL) at 6 months and event rates of major limb amputations, binary lesion restenosis, and target lesion revascularization (TLR). Pooled treatment effects were analyzed in a random effects model to account for clinical heterogeneity; the outcomes are presented as the rate ratios (RRs) and their 95% confidence intervals (CIs). Extensive meta-regression was performed to analyze potential confounders. The review was registered in the PROSPERO database (CRD42015023938; www.crd.york.ac.uk/PROSPERO).

RESULTS

Eleven RCTs with 1609 subjects (1403 claudicants and 206 patients with critical limb ischemia) with medium-length femoropopliteal lesions (mean range 5.1-11.9 cm) were included. There was consistently high-quality evidence supporting the clear superiority of PCBs in terms of reduced LLL (mean difference -0.89 mm, 95% CI -1.14 to -0.64, p<0.001), less binary restenosis (RR 0.47, 95% CI 0.37 to 0.61, p<0.001), and fewer TLR events (RR 0.33, 95% CI 0.22 to 0.49, p<0.001). Major amputations were rare in both active and control arms (pooled event rate: 0.7%, 95% CI 0.3% to 1.2%). Results were stable across all potential risk modifiers and in the presence of stents as well. There was high-quality evidence that the dose of paclitaxel was related to the magnitude of the treatment effect; standard dose (3.0-μg and 3.5-μg) PCBs were significantly more effective compared with low-dose 2-μg PCB in reducing both restenosis (RR 2.1, 95% CI 1.2 to 3.4, p<0.001) and TLR (RR 2.5, 95% CI 1.9 to 3.8, p<0.001).

CONCLUSION

PCBs reduce by more than half the rates of restenosis and TLR in the femoropopliteal artery regardless of stent placement. Biologic effect size may vary according to paclitaxel bioavailability.

The role of clinical evidence in emergent therapies: an empirical study on femoropopliteal stent-angioplasty in Europe

RATIONALE, AIMS AND OBJECTIVE

A delayed availability of clinical evidence in rapidly emerging therapies is considered a major problem. In this study, we examined whether evidence from clinical studies has influenced the therapy of a major disease in industrial countries, peripheral arterial disease (PAD), using novel femoropopliteal stent-angioplasty.

METHOD

This analysis of retrospective time series data uses multivariate linear regression to investigate associations between published clinical evidence on femoropopliteal stent-angioplasty from Q3/2004 to Q4/2010 and the demand for femoropopliteal stents in Germany, France, Italy and the UK between Q1/2005 and Q4/2010, controlling for the prevalence of PAD risk factors, cardiovascular drug demand, reimbursement of health care providers for stent implantation, stent selling prices of manufacturers and economic indicators.

RESULTS

We did not observe any association of published clinical evidence with femoropopliteal stent demand in Germany, France, Italy and the UK, while we observed such associations for varying control variables at different time lags respectively.

CONCLUSION

We observed no association between published clinical evidence of femoropopliteal stent-angioplasty and its use in any of the four countries. The country-specific context and practice-related variables at a centre and individual doctor level may have limited the role of published clinical evidence in emerging femoropopliteal stent-angioplasty. More research is needed at this context, centre and individual level.

Cryoplasty for Canine Iliac Artery Stenosis and its Impact on Expression of TIMP-2 and MMP-2

Objective:

This study was performed to observe the effects of cryoplasty on canine iliac artery stenosis and the expression of tissue inhibition of matrix metalloproteinase 2 (TIMP-2) and matrix metalloproteinase 2 (MMP-2).

Methods:

We produced a reliable canine model to mimic the atherosclerotic stenosis in the iliac artery by suturing the artery followed by vessel ligation to create an injury to intimal and medial walls. Sixteen mongrel dogs with iliac artery stenosis were randomized to conventional balloon angioplasty (n = 8) or cryoplasty (n = 8).

Results:

Four weeks posttreatment, the cryoplasty group with less collagen fibers and smooth muscle demonstrated significantly larger luminal diameter of iliac artery compared to the balloon angioplasty group ( P < .001). Expression of TIMP-2 significantly increased and expression of MMP-2 significantly reduced in iliac artery of the cryoplasty group compared to conventional balloon angioplasty.

Conclusion:

Our study suggests cryoplasty might increase the expression of TIMP-2 and decrease the expression of MMP-2, thereby inhibiting vascular hyperplasia and collagen fibers synthesis of the stenotic vessels.

Korean Guidelines for Interventional Recanalization of Lower Extremity Arteries

Peripheral arterial occlusive disease caused by atherosclerosis can present with intermittent claudication or critical limb ischemia. Proper diagnosis and management is warranted to improve symptoms and salvage limbs. With the introduction of new techniques and dedicated materials, endovascular recanalization is widely performed for the treatment of peripheral arterial occlusive disease because it is less invasive than surgery. However, there are various opinions regarding the appropriate indications and procedure methods for interventional recanalization according to operator and institution in Korea. Therefore, we intend to provide evidence based guidelines for interventional recanalization by multidisciplinary consensus. These guidelines are the result of a close collaboration between physicians from many different areas of expertise including interventional radiology, interventional cardiology, and vascular surgery. The goal of these guidelines is to ensure better treatment, to serve as a guide to the clinician, and consequently, to contribute to public health care.

Treating femoropopliteal disease: established and emerging technologies

The femoropopliteal artery is the most common site of disease in patients with peripheral arterial disease and presents some of the greatest challenges for interventional radiology. Many patients can be managed with medical treatment combined with supervised exercise alone. However, a significant proportion, especially those suffering from severe intermittent claudication or critical limb ischemia, will require some form of endovascular or surgical revascularization procedure. During the past few years an endovascular-first approach has gained support from all vascular specialties. Today, even complex lesions can be treated successfully with an endovascular approach. Unfortunately, the unique bio-mechanical properties of this vascular segment have limited long-term patency rates and clinical value of the endovascular options. In this review, the authors discuss the methods and techniques for treatment of femoropopliteal lesions and review the current evidence for commercially available devices on patency outcomes following successful recanalization.

Systematic reviews and meta-analyses for more profitable strategies in peripheral artery disease

In the peripheral arteries, a thrombus superimposed on atherosclerosis contributes to the progression of peripheral artery disease (PAD), producing intermittent claudication (IC), ischemic necrosis, and, potentially, loss of the limb. PAD with IC is often undiagnosed and, in turn, undertreated. The low percentage of diagnosis (∼30%) in this setting of PAD is of particular concern because of the potential worsening of PAD (amputation) and the high risk of adverse vascular outcomes (vascular death, coronary artery disease, stroke). A Medline literature search of the highest-quality systematic reviews and meta-analyses of randomized controlled trials documents that, due to risk of bias, imprecision, and indirectness, the overall quality of the evidence concerning diagnostic tools and antithrombotic interventions in PAD is generally low. Areas of research emerge from the information collected. Appropriate treatments for PAD patients will only derive from ad-hoc studies. Innovative imaging techniques are needed to identify PAD subjects at the highest vascular risk. Whether IC unresponsive to physical exercise and smoking cessation identifies those with a heritable predisposition to more severe vascular events deserves to be addressed. Devising ways to improve prevention of vascular events in patients with PAD implies a co-ordinated approach in vascular medicine.

Blunt microdissection for endovascular treatment of infrainguinal chronic total occlusions

PURPOSE

To present a systematic safety evaluation of the CrossBoss blunt microdissection catheter for crossing peripheral chronic total occlusions (CTOs).

METHODS

Between July 2010 and July 2011, 15 patients (all men; mean age 60.7±9.1 years) underwent endovascular treatment of 17 infrainguinal CTOs that were resistant to guidewire passage, so the blunt microdissection catheter was employed to recanalize the artery. Fourteen lesions were de novo and 3 were in-stent restenoses. Sixteen lesions were in the superficial femoral artery; 8 of 17 CTOs were TASC II type D. Extensive calcification was present in 12 lesions. Mean lesion length was 182.9±66.2 mm (range 57-296).

RESULTS

Procedural success was 100% and successful crossing without the use of a re-entry device (technical success) was achieved in 15 cases. Twelve lesions were stented. Average fluoroscopy time was 36.5±21.2 minutes (143.8±76.9 Gy*cm (2) radiaton dose area product), during which a mean 172.1±62.2 mL of iodinated contrast were used. Two patients had access site hematomas that were treated conservatively, and there was no perforation, distal embolization, amputation, or need for urgent revascularization. During the mean follow-up of 11.4±0.1 months, 1 patient died, and none required an amputation or surgical revascularization. There was a significant improvement in ankle-brachial index (0.6±0.1 to 0.8±0.2, p=0.001) and symptoms as assessed by Rutherford class at 1 year. Four of 17 limbs required secondary revascularization procedures within 1 year.

CONCLUSION

The CrossBoss blunt microdissection catheter facilitated successful crossing of CTOs in patients with infrainguinal lesions following unsuccessful guidewire crossing, with an acceptably low rate of periprocedural complications and significant improvement in symptoms.

Contemporary Management of Femoral Popliteal Revascularization

Symptomatic peripheral artery disease of the femoral popliteal segment can be treated by surgical and endovascular revascularization, but controversy exists about the best approach. Conventional approaches to revascularization have focused on lesion anatomy to decide on bypass versus endovascular treatment, but advances in endovascular therapy make an endovascular-first approach increasingly feasible-either as a single approach or as an adjunct to short-segment bypass (ie, hybrid procedure). In this review, we discuss the medical, endovascular, and surgical treatment of femoral popliteal revascularization with a special emphasis on advances in percutaneous therapy.

High-grade, non-flow-limiting dissections do not negatively impact long-term outcome after paclitaxel-coated balloon angioplasty: an additional analysis from the THUNDER study

PURPOSE

To investigate the impact of using paclitaxel-coated balloons (PCB) on outcome after post-angioplasty dissection in femoropopliteal arteries.

METHODS

The angiograms obtained in the THUNDER study (ClinicalTrials.gov identifier NCT00156624) were analyzed to compare degrees of dissection and angiographic parameters between the control (uncoated balloons, n=43) and treatment (PCBs, n=43) groups before and after the intervention and at 6-month follow-up. Furthermore, target lesion revascularizations (TLR) were documented up to 2 years.

RESULTS

In each group, 24 (56%) patients had a dissection after the intervention. At the 6-month follow-up, patients with dissection of any grade after treatment with PCBs had significantly less late lumen loss (0.4 mm) than patients with dissection after treatment with uncoated balloons (1.9 mm, p=0.001) and a lower degree of stenosis (20% vs. 51%, respectively; p=0.003). Patients with severe dissection (grades C, D, or E) especially seemed to benefit from the PCBs, with late lumen loss of 0.4 mm vs. 2.4 mm for controls (p=0.05). The binary restenosis rate was also markedly lower in the PCB group (20%) than in the uncoated group (55%, p=0.02). In the 2-year follow-up, TLR was performed in 56% of patients in the control group compared to 10% of patients in the PCB group (p=0.002).

CONCLUSION

The results of this subgroup analysis suggest that patients with dissection following treatment with a paclitaxel-coated balloon have a very acceptable outcome and stent implantation is not necessary as long as the dissection does not result in acute flow limitation.

Angioplasty versus bare metal stenting for superficial femoral artery lesions

BACKGROUND

Lower limb peripheral arterial disease (PAD) is a common, important manifestation of systemic atherosclerosis. Stenoses or occlusions in the superficial femoral artery may result in intermittent claudication or even critical ischaemia, which may be treated by balloon angioplasty with or without stenting. This is the first update of a review published in 2009.

OBJECTIVES

The primary aim was to determine the effect of percutaneous transluminal angioplasty (PTA) compared with PTA with bare metal stenting for superficial femoral artery (SFA) stenoses on vessel patency in people with symptomatic (Rutherford categories1 to 6; Fontaine stages II to IV) lower limb peripheral vascular disease.In addition, we assessed the efficacy of PTA and stenting in improving quality of life, ankle brachial index and treadmill walking distance.

SEARCH METHODS

For this update the Cochrane Peripheral Vascular Diseases Group Trials Search Co-ordinator searched the Specialised Register (last searched August 2013) and the Cochrane Central Register of Controlled Trials (CENTRAL) (2013, Issue 6).

SELECTION CRITERIA

Randomised trials of angioplasty alone versus angioplasty with bare metal stenting for the treatment of superficial femoral artery stenoses.

DATA COLLECTION AND ANALYSIS

Two review authors (MC, CT) independently selected suitable trials, assessed trial quality and extracted data. Furthermore, these two review authors performed assessments of methodological quality and wrote the final manuscript. The third review author (ADM) cross-checked all stages of the review process.

MAIN RESULTS

We include three new studies in this update, making a total of 11 included trials with 1387 participants. The average age was 69 years and all trials included men and women. Participants were followed for up to two years. There was an improvement in primary duplex patency at six and 12 months in participants treated with PTA plus stent over lesions treated with PTA alone (six months: odds ratio (OR) 2.90, 95% confidence interval (CI) 1.17 to 7.18, P = 0.02, six studies, 578 participants; 12 months: OR 1.78, 95% CI 1.02 to 3.10, P = 0.04, nine studies, 858 participants). This was lost by 24 months (P = 0.06). There was a significant angiographic patency benefit at six months (OR 2.49, 95% CI 1.49 to 4.17, P = 0.0005, four studies, 329 participants) which was lost by 12 months (OR 1.30, 95% CI 0.84 to 2.00, P = 0.24, five studies, 384 participants). Ankle brachial index (ABI) and treadmill walking distance showed no improvement at 12 months (P = 0.49 and P = 0.57 respectively) between participants treated with PTA alone or PTA with stent insertion. Three trials (660 participants) reported quality of life, which showed no significant difference between participants treated with PTA alone or PTA with stent insertion at any time interval. Antiplatelet therapy protocols and inclusion criteria regarding affected arteries between trials showed marked heterogeneity.

AUTHORS' CONCLUSIONS

Although there was a short-term gain in primary patency there was no sustained benefit from primary stenting of lesions of the superficial femoral artery in addition to angioplasty. Future trials should focus on quality of life for claudication and limb salvage for critical ischaemia.

Bayesian network meta-analysis of nitinol stents, covered stents, drug-eluting stents, and drug-coated balloons in the femoropopliteal artery

OBJECTIVE

Several randomized controlled trials (RCTs) have shown the superiority of some of these technologies over balloon angioplasty, but direct comparisons between these treatment options are lacking. The authors conducted a network meta-analysis of RCTs comparing bare nitinol stents, covered nitinol stents, paclitaxel- or sirolimus-eluting stents (PES or SES), and paclitaxel-coated balloons (PCB) with plain balloon angioplasty or with each other in the femoropopliteal artery (PROSPERO registry: CRD42013004845).

METHODS

Sixteen RCTs comprising 2532 patients with 4227 person-years of follow-up were analyzed on an intention-to-treat basis. Bayesian random effects Poisson and binomial models were used for mixed treatment comparisons (WinBUGS). Clinical heterogeneity was accounted for by incorporating a meta-regression model on trial-specific baseline risk. End points included technical success, vascular restenosis, target lesion revascularization, and major amputations. Pairwise odds ratios and rate ratios (ORs and RRs) of absolute treatment effects were calculated, and the probabilities of each treatment being best are reported. Summary estimates are reported as the posterior median and associated credible intervals (CrIs) that serve the same purpose as confidence intervals in the context of the Bayesian framework. Extensive sensitivity, meta-regression, and network consistency analyses were performed to evaluate heterogeneity.

RESULTS

Technical success was highest with covered stents (pooled OR, 13.6; 95% CrI, 3.3-31.1, probability best 82%) followed by uncovered stents (pooled OR, 7.0; 95% CrI, 2.6-129, probability best 18%) when compared with balloon angioplasty (reference treatment). Vascular restenosis was lowest with PES (RR, 0.43; 95% CrI, 0.16-1.18, probability best 45%) followed by PCB (RR, 0.43; 95% CrI, 0.26-0.67, probability best 42%). Target lesion revascularization was lowest with PCB (RR, 0.36; 95% CrI, 0.23-0.55, probability best 56%) followed by PES (RR, 0.42; 95% CrI, 0.16-1.06, probability best 33%). Major amputations were rare in all treatment and control groups (pooled amputation rate of 0.7 events per 100 person-years).

CONCLUSIONS

Immediate technical success is better with the use of covered stents, whereas paclitaxel-eluting stents and paclitaxel-coated balloons offer the best long-term results in the femoropopliteal artery.

Endovascular recanalization of infrapopliteal occlusions in patients with critical limb ischemia

BACKGROUND

Endovascular therapies are increasingly used for treatment of critical limb ischemia (CLI). Infrapopliteal (IP) occlusions are common in CLI, and successful limb salvage may require restoration of arterial flow in the distribution of a chronically occluded vessel. We sought to describe the procedural characteristics and outcomes of patients with IP occlusions who underwent endovascular intervention for treatment of CLI.

METHODS

All patients with IP interventions for treatment of CLI from 2006 to 2012 were included. Angiographic and procedural data were compared between patients who underwent intervention for IP occlusions vs IP stenosis. Restenosis was determined by Doppler ultrasound imaging. Limb salvage was the primary end point of the study. Additional end points included primary patency, primary assisted patency, secondary patency, occlusion crossing success, procedural success, and amputation-free survival.

RESULTS

A total of 187 patients with CLI underwent interventions for 356 IP lesions, and 77 patients (41%) had interventions for an IP occlusion. Patients with an intervention for IP occlusion were more likely to have zero to one vessel runoff (83% vs 56%; P < .001) compared with interventions for stenosis. Compared with IP stenoses, IP occlusions were longer (118 ± 86 vs 73 ± 67 mm; P < .001) and had a smaller vessel diameter (2.5 ± 0.8 vs 2.7 ± 0.5 mm; P = .02). Wire crossing was achieved in 83% of IP occlusions, and the overall procedural success for IP occlusions was 79%. The overall 1-year limb salvage rate was 84%. Limb salvage was highest in the stenosis group, slightly lower in the successful occlusion group, and lowest in the failed occlusion group (92% vs 75% vs 58%, respectively; P = .02). Unsuccessfully treated IP occlusions were associated with a significantly higher likelihood of major amputation (hazard ratio, 5.79; 95% confidence interval, 1.89-17.7) and major amputation or death (hazard ratio, 2.69; 95% confidence interval, 1.09-6.63).

CONCLUSIONS

Successful endovascular recanalization of IP occlusions can be achieved with guidewire and support catheter techniques in most patients. In patients selected for an endovascular-first approach for IP occlusions in CLI, this strategy can be successfully implemented with favorable rates of limb salvage.

Primary nitinol stenting in femoropopliteal occlusive disease: a meta-analysis of randomized controlled trials

PURPOSE

To determine the efficacy and safety of balloon angioplasty (BA) with optional stenting vs. routine stenting with current open cell nitinol stents for femoropopliteal occlusive disease by analyzing the overall results from all available randomized controlled trials.

METHODS

A bibliographic search of electronic medical databases (MEDLINE, Embase, ISI Web of Knowledge, and the Cochrane Central Register of Controlled Trials) was conducted to identify relevant articles from 1960 to July 2011. Of the 701 published articles retrieved, 17 clinical trials randomized patients with symptomatic femoropopliteal occlusive disease to either primary BA or primary stenting. Of these, 4 RCTs involved the use of currently employed high flexibility nitinol stents. Thirteen other trials that employed obsolete, steel, or coated stents were excluded. The technical success rate, the target lesion revascularization (TLR) rate, and the binary restenosis rate at 12 months were primary efficacy endpoints; mortality was the primary safety endpoint. The results are reported as the odds ratio (OR) with 2-tailed 95% confidence intervals (95% CI).

RESULTS

The study population was made up of 627 patients (416 men; mean age 67±10 years) and 665 lesions (361 assigned to the primary stenting and 304 to BA). The mean length of the treated lesion was similar in both groups (74.6±45.7 mm in the stenting group vs. 66.7±41.3 mm in the BA group). Technical success was significantly higher in the stenting group compared to BA (95.8% vs. 64.2%; OR 0.31, 95% CI 0.09 to 0.92, p<0.001). Follow-up ranged from 12 to 24 months. Based on 3 studies, the TLR at 12 months favored the stent group (OR 2.47, 95% CI 0.72 to 8.49, p=0.065), but the difference did not reach statistical significance. However, the 12-month binary restenosis rate was significantly lower in the primary stenting group (OR 3.02, 95% CI 1.3 to 6.71, p<0.001). With respect to the safety endpoint, mortality was similar in both groups (OR 0.83, 95% CI 0.39 to 1.77, p<0.001).

CONCLUSION

This meta-analysis supports the use of the primary stenting, mainly for long lesions, as a first-line endovascular treatment for symptomatic disease in the femoropopliteal segment, contrary to indications for use in current clinical guidelines.

Patterns of femoropopliteal recurrence after routine and selective stenting endoluminal therapy

OBJECTIVE

This study determined the incidence and characteristics of recurrent disease after femoropopliteal angioplasty, following either selective or routine stenting of diseased site(s).

METHODS

Retrospective analysis of a prospectively maintained database for femoropopliteal interventions from June 2003 to July 2010 was performed. Interventions during this period were from a single institution, followed up at 1, 3, and 6 months after initial intervention and on a semiannual basis thereafter with clinical examinations and duplex ultrasound imaging. Two groups were identified: those with routine stenting (RS; routine stenting for all diseased areas) and those with selective stenting (SS; selective stenting for only segments which exhibited compromised flow from residual stenosis or significant dissection). Patients who developed recurrent symptoms (claudication, rest pain), a decrease in ankle-brachial index (ABI) (>0.2), or duplex documentation of a significant (>80%) recurrent stenosis underwent reintervention. Patient demographics, comorbidities, Trans-Atlantic Inter-Society Consensus (TASC) II classification, runoff, and degree of calcification (none, mild, moderate, severe) at initial intervention were recorded. The time to reintervention and recurrence pattern were recorded for both groups.

RESULTS

During the study period, 746 endovascular interventions in 477 patients were performed. Total reintervention rate, including bypass, amputation, and asymptomatic occlusion after initial intervention, was 36.48% (group SS, 42.9%; group RS, 33.1%; P=.04). Of all initial interventions, 182 endovascular reinterventions in 165 patients for recurrent femoropopliteal disease were identified (group SS, 70; group RS, 95). No differences were noted among the groups in gender, comorbidities, initial TASC II classification, run off, calcification scores, or statin or clopidogrel use, or both. Time to recurrence was similar in the RS and SS groups. TASC II classification, runoff score, and degree of calcification were similar between the two groups. Although not statistically significant, analysis of recurrence pattern demonstrated de novo stenosis was more common in the SS group (50.0% vs 34.7%; P=.06).

CONCLUSIONS

This single-center retrospective study found a significant difference in the incidence of recurrence requiring reintervention between patients treated with selective and routine stenting for femoropopliteal disease. Analysis of endovascular reinterventions, however, reveals no significant difference in recurrence time or recurrence pattern between the two groups. No significant differences were identified in time to recurrence, TASC II classification, runoff, and calcification of endovascular reinterventions between the two groups' end points. Additional prospective studies to evaluate the roles of routine and selective stenting in symptomatic femoropopliteal peripheral arterial disease and to investigate recurrence lesion characteristics and the patency of multiple endovascular interventions between these two groups are needed.

Predictors of provisional stenting in patients undergoing lower extremity arterial interventions

Predictors of provisional stenting in patients undergoing lower extremity arterial interventions remain unclear. We performed an ad hoc analysis on the predictors of provisional stenting during infrainguinal arterial percutaneous interventions using data from the Percutaneous Lower Extremity Arterial Interventions Using Primary Balloon Angioplasty versus Silverhawk Atherectomy (SA) and Adjunctive Balloon Angioplasty trial. In the above trial, SA of infrainguinal de novo arterial lesions was shown to reduce significantly provisional stenting compared with primary percutaneous transluminal angioplasty (PTA). In this ad hoc analysis, patients were divided into two groups based on whether provisional stenting has occurred. Univariate analysis was conducted between the stent versus the no-stent group. Logistic regression (LR) analysis was performed to model for the predictors of provisional stenting. Variables included were diabetes, presence of moderate calcification (versus none to little), age, gender, hypercholesterolemia, Transatlantic Intersociety Consensus (TASC) D lesion (vs. TASC A to C), and treatment method (primary PTA vs. SA with adjunctive PTA). By LR analysis, predictors of stenting were as follows: moderate calcification (odds ratio [OR] 6.56, 95% confidence interval [CI] 1.21 to 35.56, p = 0.029), primary PTA (vs. SA) (OR 0.19, 95% CI 0.04 to 0.93, p = 0.04), and TASC D lesions (vs. A to C) (OR 0.10, 95% CI 0.01 to 0.87, p = 0.037). Provisional stenting in infrainguinal interventions is predicted by the use of primary PTA, presence of moderate calcification, and TASC D lesions after controlling for gender, age, hypercholesterolemia, and diabetes.

Antithrombotic therapy in peripheral artery disease: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines

BACKGROUND

This guideline focuses on antithrombotic drug therapies for primary and secondary prevention of cardiovascular disease as well as for the relief of lower-extremity symptoms and critical ischemia in persons with peripheral arterial disease (PAD).

METHODS

The methods of this guideline follow those described in Methodology for the Development of Antithrombotic Therapy and Prevention of Thrombosis Guidelines: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines in this supplement.

RESULTS

The most important of our 20 recommendations are as follows. In patients aged ≥ 50 years with asymptomatic PAD or asymptomatic carotid stenosis, we suggest aspirin (75-100 mg/d) over no therapy (Grade 2B) for the primary prevention of cardiovascular events. For secondary prevention of cardiovascular disease in patients with symptomatic PAD (including patients before and after peripheral arterial bypass surgery or percutaneous transluminal angioplasty), we recommend long-term aspirin (75-100 mg/d) or clopidogrel (75 mg/d) (Grade 1A). We recommend against the use of warfarin plus aspirin in patients with symptomatic PAD (Grade 1B). For patients undergoing peripheral artery percutaneous transluminal angioplasty with stenting, we suggest single rather than dual antiplatelet therapy (Grade 2C). For patients with refractory claudication despite exercise therapy and smoking cessation, we suggest addition of cilostazol (100 mg bid) to aspirin (75-100 mg/d) or clopidogrel (75 mg/d) (Grade 2C). In patients with critical limb ischemia and rest pain unable to undergo revascularization, we suggest the use of prostanoids (Grade 2C). In patients with acute limb ischemia due to acute thrombosis or embolism, we recommend surgery over peripheral arterial thrombolysis (Grade 1B).

CONCLUSIONS

Recommendations continue to favor single antiplatelet therapy for primary and secondary prevention of cardiovascular events in most patients with asymptomatic PAD, symptomatic PAD, and asymptomatic carotid stenosis. Additional therapies for relief of limb symptoms should be considered only after exercise therapy, smoking cessation, and evaluation for peripheral artery revascularization.

Oversizing and restenosis with self-expanding stents in iliofemoral arteries

PURPOSE

Uncoated self-expanding nitinol stents (NS) are commonly oversized in peripheral arteries. In current practice, 1-mm oversizing is recommended. Yet, oversizing of NS may be associated with increased restenosis. To provide further evidence, NS were implanted in porcine iliofemoral arteries with a stent-to-artery-ratio between 1.0 and 2.3. Besides conventional uncoated NS, a novel self-expanding NS with an antiproliferative titanium-nitride-oxide (TiNOX) coating was tested for safety and efficacy.

METHODS

Ten uncoated NS and six TiNOX-coated NS (5-6 mm) were implanted randomly in the iliofemoral artery of six mini-pigs. After implantation, quantitative angiography (QA) was performed for calculation of artery and minimal luminal diameter. Follow-up was performed by QA and histomorphometry after 5 months.

RESULTS

Stent migration, stent fracture, or thrombus formation were not observed. All stents were patent at follow-up. Based on the location of the stent (iliac/femoral) and the stent-to-artery-ratio, stent segments were divided into "normal-sized" (stent-to-artery-ratio < 1.4, n = 12) and "oversized" (stent-to-artery-ratio ≥ 1.4, n = 9). All stent segments expanded to their near nominal diameter during follow-up. Normal-sized stent segments increased their diameter by 6% and oversized segments by 29%. A significant correlation between oversizing and restenosis by both angiography and histomorphometry was observed. Restenosis rates were similar for uncoated NS and TiNOX-coated NS.

CONCLUSIONS

TiNOX-coated NS are as safe and effective as uncoated NS in the porcine iliofemoral artery. All stents further expand to near their nominal diameter during follow-up. Oversizing is linearly and positively correlated with neointimal proliferation and restenosis, which may not be reduced by TiNOX-coating.