Prescribing patterns of antiplatelet agents are highly variable after lower extremity endovascular procedures

A Qualitative Systematic Review of Endovascular Management of Renal Artery Aneurysms

PURPOSE

To perform a qualitative systematic review of endovascular management of renal artery aneurysms (RAAs).

MATERIALS AND METHODS

A comprehensive electronic search of PubMed, MEDLINE, Embase, Google Scholar, and Cochrane databases from 2000 to 2022 was performed using the search terms "renal artery," "aneurysm," and "endovascular." Means of outcome measures were calculated with a primary end point focused on RAA-related mortality and rupture. Secondary end points included reintervention rate and renal infarction.

RESULTS

Twenty-six, single-center, retrospective, observational studies were included. There were 454 RAAs treated in 427 patients using endovascular techniques. Mean age was 53.8 years, with a female predominance (62%). A variety of endovascular treatments of RAA were used with excellent technical success (96%), renal parenchymal preservation, and a low rate of moderate/severe adverse events (AEs). Primary coil embolization was the most commonly used technique (44.7%). There was an overall AE rate of 22.9%, of which 6.7% were moderate/severe and there was 0% periprocedural mortality. The most common AE was renal infarction (49 patients, 11.5%); however, renal function was preserved in 84% of patients. Nephrectomy rate was 0.4%. Computed tomography (CT) angiography was the most common imaging follow-up modality used in 72% of studies. Only 9 studies (34%) reported anticoagulant use. Although the risk of delayed aneurysm reperfusion warrants clinical and imaging surveillance, relatively few patients (3%) required reintervention in this cohort.

CONCLUSIONS

Endovascular management of RAA is a technically feasible treatment option with low rates of AEs and reintervention. The present study highlights the techniques available for interventional radiologists, a need for standardization of AE reporting, anticoagulation therapy, and follow-up imaging.

Patient Factors Influencing Prescription of Antithrombotic Medication After Lower Limb Endovascular Intervention

OBJECTIVE

There is significant practice variation in the use of antithrombotic therapy after endovascular intervention for lower limb peripheral arterial disease, with differences in medication choice and duration. Prescriber decision making is complex, and patient factors have been shown to substantially contribute to prescribing variation. To determine the influence of patient factors on antithrombotic prescribing, a discrete choice experiment was distributed to vascular surgeons and trainees across Australia and Aotearoa New Zealand.

METHODS

After pilot testing, the discrete choice experiment questionnaire was distributed to 300 vascular surgeons and trainee members of the Australian and New Zealand Society for Vascular Surgery. Multinomial logistic regression models were used to analyse patient factors that had the most influence on decisions to prescribe a second antithrombotic agent, and the preferred choice of antithrombotic (clopidogrel 75 mg daily or rivaroxaban 2.5 mg twice daily) in addition to aspirin 100 mg daily. The odds ratio (OR) with 95% confidence interval (CI) reported preference strength.

RESULTS

A total of 44 questionnaires were completed between September and October 2023, reaching the 15% targeted response rate. Prescribing a second antithrombotic was more likely after femoropopliteal stenting compared with angioplasty (OR 1.89, 95% CI 1.20 - 2.13), and in chronic limb threatening ischaemia compared with intermittent claudication (OR 1.58, 95% CI 1.20 - 2.13). Most respondents preferred clopidogrel over rivaroxaban (62%), with over a third of respondents exclusively prescribing clopidogrel. Patients with stents (OR 1.77, 95% CI 1.32 - 2.37) or moderate bleeding risk (OR 1.38, 95% CI 0.97 - 1.84) were more likely to receive clopidogrel than rivaroxaban.

CONCLUSION

This study demonstrates that vascular surgeons primarily prioritise antithrombotic prescribing decisions by procedure type. Clopidogrel is more likely to be prescribed than rivaroxaban as a second agent in combination with aspirin, especially after stenting. Knowing these clinician preferences can target implementation strategies towards supporting decision making in subgroups of patients according to individual risk profiles.

Medical Therapy for Secondary Prevention of Atherothrombotic Events in Peripheral Artery Disease

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Short-Term Clinical Outcomes of Single Versus Dual Antiplatelet Therapy after Infrainguinal Endovascular Treatment for Peripheral Arterial Disease

After infrainguinal endovascular treatment for peripheral arterial disease (PAD), it is uncertain whether single antiplatelet therapy (SAPT) or dual antiplatelet therapy (DAPT) should be preferred. This study investigated major adverse limb events (MALE) and major adverse cardiovascular events (MACE) between patients receiving SAPT and DAPT. Patient data from three centers in the Netherlands were retrospectively collected and analyzed. All patients treated for PAD by endovascular revascularization of the superficial femoral, popliteal, or below-the-knee (BTK) arteries and who were prescribed acetylsalicylic acid or clopidogrel, were included. End points were 1-, 3-, and 12-month MALE and MACE, and bleeding complications. In total, 237 patients (258 limbs treated) were included, with 149 patients receiving SAPT (63%) and 88 DAPT (37%). No significant differences were found after univariate and multivariate analyses between SAPT and DAPT on 1-, 3-, and 12-month MALE and MACE, or bleeding outcomes. Subgroup analyses of patients with BTK treatment showed a significantly lower 12-month MALE rate when treated with DAPT (hazard ratio 0.33; 95% confidence interval 0.12-0.95; p = 0.04). In conclusion, although patient numbers were small, no differences were found between SAPT and DAPT regarding MALE, MACE, or bleeding complications. DAPT should, however, be considered over SAPT for the subgroup of patients with below-the-knee endovascular treatment.

Kissing Stent Technique for TASC C-D Lesions of Common Iliac Arteries: Clinical and Anatomical Predictors of Outcome

BACKGROUND

The endovascular treatment of peripheral artery obstructive disease in Trans-Atlantic Inter-Society (TASC) C and D lesions involving the aortic bifurcation is a matter of debate. The aim of this study is to evaluate the technical and clinical success of kissing stenting in this context and to analyze predictors of outcome.

METHODS

All patients treated for aortoiliac TASC C and D lesions with kissing stenting (from 2012 to 2017) in a 6-year period were retrospectively analyzed. Preoperative anatomical features were evaluated by reviewing computed tomography angiography images to identify severe iliac calcifications (SICs) versus not SIC (NSICs). Primary end points were as follows: technical success (TS), procedural success, primary patency (PP), and clinical success (CS). Secondary end points were as follows: secondary patency, assisted patency, survival, mid-term procedure-related complications, and risk factors that affected TS and mid-term results.

RESULTS

In a 6-year period, 51 patients fulfilled the inclusion criteria. TS was achieved in 49 (96.1%) cases. Thirty-one patients (60.8%) received a dual antiplatelet therapy (DAPT) for at least 1 month after the procedure. 30-day CS was 94.1%. Median follow-up was 45.7 months (IQR: 24.5, 8-86 range). The CS was 92.6% at 3 years, with a PP of 86.8% and a secondary patency of 93.2% at 3 years. Six (13.2%) iliac axis occluded during the first follow-up year. NSIC was statistically and independently associated with a lower PP (73% vs. 96%, P = 0.03); DAPT was statistically and independently associated with higher PP than single antiplatelet therapy (96% vs. 75%, P = 0.03); these results were confirmed by Cox regression analysis (HR: 0.14, 95%, IC: 0.01-0.89, P = 0.05 for DAPT analysis; HR: 6.8, 95%, IC: 1.21-59, P = 0.05 for NSIC analysis).

CONCLUSIONS

Endovascular treatment for TASC C-D is an effective technique. Postoperative stent occlusion is higher in patients with no DAPT and it usually occurs during the first postoperative year. Preoperative NSIC lesions are associated with reduced PP at 3 years of follow-up.

Effects of dual antiplatelet therapy on graft patency after lower extremity bypass

OBJECTIVE

Current guidelines recommend single-agent antiplatelet therapy for patients with symptomatic peripheral artery disease and consideration of dual antiplatelet therapy (DAPT) after surgical revascularization. The objective of this study was both to explore prescribing patterns of single antiplatelet therapy vs DAPT after lower extremity bypass surgery and to investigate the effects of antiplatelet therapy on bypass graft patency.

METHODS

A retrospective analysis of prospectively collected nonemergent infrainguinal lower extremity bypass operations entered in the national Vascular Quality Initiative (2003-2018) with captured long-term follow-up was performed. Patients discharged on aspirin monotherapy or DAPT were identified. Linear regression investigated temporal trends in antiplatelet use. Multivariable Cox regression investigated predictors of primary, primary assisted, and secondary patency.

RESULTS

Of the 13,020 patients investigated, 52.2% were discharged on aspirin monotherapy and 47.8% on DAPT. The proportion of patients discharged on DAPT increased from 10.6% in 2003 to 60.6% in 2018 (P < .001). The DAPT cohort was younger, had higher rates of medical (hypertension, diabetes, congestive heart failure, chronic obstructive pulmonary disease) and atherosclerotic (coronary artery disease, prior coronary artery bypass graft or percutaneous coronary intervention, prior lower extremity intervention) comorbidities, and had higher risk bypass procedures (more distal targets, prior inflow bypass procedure, prosthetic conduit use). Multivariable Cox regression analysis did not show any difference between the DAPT and aspirin cohorts in primary patency (hazard ratio [HR], 0.98; 95% confidence interval [CI], 0.88-1.10; P = .78), primary assisted patency (HR, 0.93; 95% CI, 0.80-1.07; P = .30), or secondary patency (HR, 0.88; 95% CI, 0.74-1.06; P = .18). On subgroup analysis based on bypass conduit, DAPT was found to have a protective effect on patency only in the prosthetic bypass cohort (primary patency: HR, 0.81 [95% CI, 0.66-1.00; P = .05]; primary assisted patency: HR, 0.74 [95% CI, 0.58-0.94; P = .01]; and secondary patency: HR, 0.60 [95% CI, 0.44-0.82; P < .001]). No patency differences were observed on adjusted subgroup analysis for the other bypass conduits.

CONCLUSIONS

A significant and increasing proportion of patients are discharged on DAPT after lower extremity bypass revascularization. These patients represent a higher risk cohort with more medical comorbidities and higher risk bypass features. After controlling for these differences, DAPT therapy had no beneficial effect on overall bypass graft patency or major adverse limb events. However, on subgroup analysis, DAPT was associated with improved bypass graft patency in patients receiving prosthetic bypass conduits. Further study is warranted to investigate optimal duration of DAPT therapy and its possible bleeding complications in prosthetic bypass patients.

Selective Use of Anticoagulation or Dual Antiplatelet Therapy for Patients with Extra-anatomic Bypasses

BACKGROUND

The benefit of long-term anticoagulation or dual antiplatelet therapy (DAPT) for patients with extra-anatomic bypasses to the lower extremity remains poorly defined. Our study analyzed the real-world use of antithrombotic therapy in patients with extra-anatomic bypass grafts to the lower extremity and compared graft and patient outcomes by antithrombotic regimen.

METHODS

We studied patients who underwent axillofemoral or femoral-femoral bypass within the Vascular Quality Initiative with one-year follow-up data. Primary exposures were anticoagulation and DAPT, at the time of index procedure and one-year follow-up. Primary outcomes were major adverse limb events (MALE) defined as reintervention or above-ankle amputation, and primary patency. Secondary outcomes included perioperative blood transfusion requirements and the need for reoperation specifically for bleeding. We analyzed outcomes using the Kaplan-Meier estimation and examined factors associated with choice of antithrombotic therapy via logistic regression.

RESULTS

Our cohort included 2,760 patients (axillofemoral bypass, n = 857; femoral-femoral bypass, n = 1,903) across 168 centers from 2009 to 2018. Mean age was 66.5 ± 10.5 years and 59% were male. Patients were infrequently prescribed long-term anticoagulation (19%) or DAPT (22%). One-year primary patency was 86% and was similar by anticoagulation (log-rank P = 0.12) and DAPT status (log-rank P = 0.26). Freedom from MALE was 87% at 1 year and was slightly inferior for patients on anticoagulation (88 vs. 83%, log-rank P = 0.001) but was similar by DAPT (log-rank P = 0.19). Transfusion was more common in patients who were anticoagulated than those who were not (30 vs. 25%, P < 0.01), but there was no increase in reoperation because of bleeding (anticoagulation 0.8 vs. 0.8, P = 0.98). Anticoagulation was more commonly prescribed according to disease severity, such as rest pain (adjusted odds ratio (OR): 1.6 (95% confidence interval (CI): 1.20-2.20), tissue loss (OR: 1.9, CI: 1.28-2.73), or acute limb ischemia (OR: 1.9, CI: 1.35-2.71) or prior bypass graft (OR: 2.6, CI: 2.07-3.35). Patients were more commonly prescribed DAPT according to comorbidities, including hypertension (OR: 1.4, CI: 1.04-1.94) and coronary artery disease (OR: 1.6, CI 1.26-1.95).

CONCLUSIONS

Antithrombotics are selectively used in patients with extra-anatomic bypass to the lower extremity, the selection of which appears associated with disease severity for anticoagulants and patient comorbidities for DAPT. Primary patency and MALE rates are similar with focused utilization of anticoagulants or DAPT. Blood transfusions are more common among patients on antithrombotics without a difference in the need for reoperation for bleeding.

Antithrombotics in stable peripheral artery disease

Patients with peripheral artery disease (PAD) are at high risk for ischemic cardiovascular complications. While single antiplatelet therapy (SAPT), predominantly aspirin, has long been the standard antithrombotic treatment in stable PAD, there have now been greater than 40,000 PAD patients randomized to varying antiplatelet and/or anticoagulant regimens. In this review, we provide a summary of the current evidence for antithrombotics in stable PAD, focusing on the rates of major adverse cardiovascular events (MACE), major adverse limb events (MALE), and major bleeding. SAPT has a limited role in the treatment of asymptomatic PAD, particularly in the absence of concomitant coronary artery disease. In symptomatic PAD, SAPT is effective in preventing MACE, though treatment with a thienopyridine appears marginally superior to aspirin. Dual antiplatelet therapy (DAPT) suggests benefit over SAPT in reducing MACE and MALE, though studies to date are not conclusive and/or are associated with excess major bleeding. Combining moderate to high intensity vitamin K antagonists with antiplatelet therapy does not reduce MACE or MALE and increases life-threatening bleeding. Rivaroxaban 2.5 mg BID in addition to aspirin reduces the incidence of both MACE and MALE as compared to aspirin alone, without increasing life-threatening bleeding. This regimen is associated with a reduced severity of MALE when it does occur. Comparisons across antithrombotic trials in PAD are challenging given the heterogeneity of patient populations and the differing assessment of outcomes. The vascular medicine practitioner can reduce ischemic cardiac and limb events, as well as minimize life-threatening bleeding, by choosing the optimal antithrombotic regimen in their PAD patients.

Clopidogrel Resistance in Lower Extremity Arterial Endovascular Interventions

Antiplatelet pharmacotherapy for endovascular interventions has been widely adopted, with clopidogrel being one of the most common agents prescribed. A fraction of patients is resistant to clopidogrel resulting in decreased platelet inhibition despite adequate use. This finding is often termed high on-treatment platelet reactivity (HPR) and may lead to decreased patency in lower extremity arterial endovascular interventions. Current literature on HPR with lower extremity arterial endovascular interventions is limited to only a few studies. Resistance to clopidogrel is largely a result of CYP2C19 enzyme loss of function alleles. Several tests are available to measure clopidogrel resistance but light transmittance aggregometry remains the gold standard, yet direct genetic testing may be more reliable. One-year patency rates following lower extremity arterial endovascular interventions in patients with clopidogrel resistance (HPR) range between 35%-83% whereas those with the proper response to clopidogrel range between 73%-100%. Patients with decreased CYP2C19 activity show a significant decrease in one-year patency of endovascular femoropopliteal interventions (35% vs. 73%; p=0.006). Among patients tested for platelet function after in-stent thrombosis, up to 53% are resistant to clopidogrel. Lack of robust data limits our ability to predict patency in lower extremity arterial interventions for patients with HPR, but there is little doubt that longer patency seems to favor non-HPR patients. Large population, prospective trials are needed to guide our practice.

Cell transfer technology for tissue engineering

We recently developed novel cell transplantation method “cell transfer technology” utilizing photolithography. Using this method, we can transfer ex vivo expanded cells onto scaffold material in desired patterns, like printing of pictures and letters on a paper. We have investigated the possibility of this novel method for cell-based therapy using several disease models. We first transferred endothelial cells in capillary-like patterns on amnion. The transplantation of the endothelial cell-transferred amnion enhanced the reperfusion in mouse ischemic limb model. The fusion of transplanted capillary with host vessel networks was also observed. The osteoblast- and periodontal ligament stem cell-transferred amnion were next transplanted in bone and periodontal defects models. After healing period, both transplantations improved the regeneration of bone and periodontal tissues, respectively. This method was further applicable to transfer of multiple cell types and the transplantation of osteoblasts and periodontal ligament stem cell-transferred amnion resulted in the improved bone regeneration compared with single cell type transplantation. These data suggested the therapeutic potential of the technology in cell-based therapies for reperfusion of ischemic limb and regeneration of bone and periodontal tissues. Cell transfer technology is applicable to wide range of regenerative medicine in the future.

State transition model: vorapaxar added to standard antiplatelet therapy to prevent thrombosis post myocardial infarction or peripheral artery disease

OBJECTIVE

To evaluate long-term health benefits and risks of adding vorapaxar (VOR) to the standard care antiplatelet therapy (SC) of aspirin and/or clopidogrel, among a population with a recent myocardial infarction (MI) and/or peripheral artery disease (PAD).

RESEARCH DESIGN AND METHODS

In a state-transition model, patients transition between health states (event-free, recurrent MI, stroke, death), while at risk of experiencing non-transition-related revascularization and non-fatal bleeding events. Risk equations developed from the TRA 2°P-TIMI 50 trial's patient-level data were used to predict cardiovascular (CV) outcomes over longer time horizons. Additional sources, including trials and US-based observational studies, informed the inputs for short-term CV risk, non-CV death, and health-related quality of life. Survival and quality-adjusted life-years (QALYs) were estimated over a lifetime horizon, discounted at 3% per year.

RESULTS

Within a cohort of 7361 patients with recent MI and/or PAD, VOR + SC relative to SC alone yielded 176 fewer CV events (MIs, strokes, or CV deaths), but 27 more major bleeding events. VOR + SC was associated with increased life expectancy and health benefits (19.93 undiscounted life-years [LYs], 9.57 discounted QALYs vs. 19.61 undiscounted LYs, 9.41 discounted QALYs). The results were most sensitive to scenarios varying time of vorapaxar initiation, and the assumptions in the 90 day period post-MI. Additional analyses showed that add-on vorapaxar provides consistent incremental benefits in high-risk subgroups.

CONCLUSION

This study contributes to the growing literature on secondary prevention add-on therapy, as results from these modeling analyses suggest that adding vorapaxar to SC for patients at high atherothrombotic risk can provide long-term health benefits.

Peripheral interventions and antiplatelet therapy: Role in current practice

Peripheral arterial disease (PAD) is a common disorder associated with a high risk of cardiovascular mortality and continues to be under-recognized. The major risk factors for PAD are similar to those for coronary and cerebrovascular disease. Management includes exercise program, pharmacologic therapy and revascularization including endovascular and surgical approach. The optimal revascularization strategy, endovascular or surgical intervention, is often debated due to the paucity of head to head randomized controlled studies. Despite significant advances in endovascular interventions resulting in increased utilization over surgical bypass, significant challenges still remain. Platelet activation and aggregation after percutaneous transluminal angioplasty of atherosclerotic arteries are important risk factors for re-occlusion/restenosis and life-threatening thrombosis following endovascular procedures. Antiplatelet agents are commonly prescribed to reduce the risk of myocardial infarction, stroke and death from cardiovascular causes in patients with PAD. Despite an abundance of data demonstrating efficacy of antiplatelet therapy in coronary artery disease and cerebrovascular disease, there is a paucity of clinical information, clinical guidelines and randomized controlled studies in the PAD population. Hence, data on antiplatelet therapy in coronary interventions is frequently extrapolated to peripheral interventions. The aim of this review article is to elucidate the current data on revascularization and the role and duration of antiplatelet and anticoagulant therapy in re-vascularized lower limb PAD patients.

Percutaneous Therapies for Peripheral Artery Disease

Percutaneous therapies for peripheral artery disease continue to evolve with new techniques and devices. Although guidelines-recommended therapies have impacted cardiovascular morbidity and mortality, endovascular interventions have been shown to reduce limb pain, improve quality of life, and prolong walking distance for those with claudication and to reduce amputation rates among those with critical limb ischemia. Novel devices such as drug-eluting stents and drug-coated balloons have improved patency for moderate-length lesions, whereas others allow treatment of heavily calcified and tortuous segments. New adjunctive devices to cross lesions and reduce or modify associated plaque have also been developed, although level 1 data regarding their efficacy are sparse. There has also been a better mechanistic understanding of lower extremity endovascular treatment using tools such as intravascular ultrasound. This information has highlighted the need for better stent size selection for the femoropopliteal arterial segments and larger balloon diameters for the tibial arteries. Moreover, a wound perfusion approach with direct in-line flow, the so-called angiosome approach, and reconstruction of the pedal loop have been advocated for improved wound healing. Technical advances such as the tibiopedal access and reentry methods have allowed crossing of lesions that were considered no option for the endovascular approach in the past. Collectively, there has been increased awareness, interest, and commitment by various specialty societies and organizations to advance the treatment of peripheral artery disease and critical limb ischemia. This is also evident by the recent coalition of 7 professional societies and organizations that represented >150 000 allied health professionals and millions of patients with peripheral artery disease at the 2015 Centers for Medicaid and Medicare Services Medicare Evidence Development and Coverage Analysis Committee meeting. The percutaneous therapies for peripheral artery disease continue to evolve with longer follow-up with randomized data and larger prospective registries. In the future, it is hopeful that we will treat the lower extremity arteries according to segments, taking into account plaque morphology, luminal versus subintimal crossing, location, and stenotic versus occlusive disease. Until then, we must identify the most cost-effective, efficacious, and safe treatment for each patient. The goal of this article is to aid the practicing vascular specialist consider the optimal choices for the management of patients with vascular disease.

Lumbar sympathectomy techniques for critical lower limb ischaemia due to non-reconstructable peripheral arterial disease

BACKGROUND

Critical lower limb ischaemia (CLI) is a manifestation of peripheral arterial disease (PAD) that is seen in patients with typical chronic ischaemic rest pain or patients with ischaemic skin lesions - ulcers or gangrene - for longer than 2 weeks. Critical lower limb ischaemia is the most severe form of PAD, and interventions to improve arterial perfusion become necessary. Although surgical bypass has been the gold standard for revascularisation, the extent or the site of disease may be such that the artery cannot be reconstructed or bypassed. These patients require other modalities of treatment, for example, vasodilatation by drugs or lumbar sympathectomy to relieve pain at rest and to avoid amputations. A systematic review of randomised controlled trials is required to evaluate the effects of lumbar sympathectomy in treating patients with CLI due to non-reconstructable PAD.

OBJECTIVES

The objective of this review is to assess the effects of lumbar sympathectomy by open, laparoscopic and percutaneous methods compared with no treatment or compared with any other method of lumbar sympathectomy in patients with CLI due to non-reconstructable PAD.

SEARCH METHODS

The Cochrane Vascular Information Specialist (CIS) searched the Specialised Register (January 2016) and the Cochrane Central Register of Controlled Trials (CENTRAL; 2015, Issue 12). In addition, the CIS searched clinical trials databases for details of ongoing and unpublished studies.

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing any of the treatment modalities of lumbar sympathectomy, such as open, laparoscopic and chemical percutaneous methods, with no treatment or with any other method of lumbar sympathectomy for CLI due to non-reconstructable PAD were eligible. To decrease the bias of including participants that may be incorrectly diagnosed with CLI, review authors defined CLI as persistently recurring ischaemic rest pain requiring regular analgesia for more than two weeks, or ulceration or gangrene of the foot or toes, attributable to objectively proven arterial occlusive disease by measurement of ankle pressure of < 50 mmHg or toe pressure < 30 mmHg. We defined non-reconstructable PAD as a resting ankle brachial index (ABI) < 0.9 when no reasonable open surgical or endovascular revascularisation treatment option is available, as determined by individual trial vascular specialists.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed studies identified for potential inclusion in the review. We planned to conduct data collection and analysis in accordance with the Cochrane Handbook for Systematic Review of Interventions.

MAIN RESULTS

We identified no studies that met the predefined inclusion criteria. To decrease the bias of including participants who may be incorrectly diagnosed with CLI, we based our inclusion criteria on objective tests, as described above. The randomised trials identified by the literature search were performed before such objective criteria for selection were applied and therefore were not eligible for inclusion in the review.

AUTHORS' CONCLUSIONS

We identified no RCTs assessing effects of lumbar sympathectomy by open, laparoscopic and percutaneous methods compared with no treatment or compared with any other method of lumbar sympathectomy in patients with CLI due to non-reconstructable PAD. High-quality studies are needed.

A network meta-analysis of randomized controlled trials comparing treatment modalities for de novo superficial femoral artery occlusive lesions

BACKGROUND

Treatment of superficial femoral artery (SFA) lesions remains challenging. We conducted a network meta-analysis of randomized controlled trials aiming to explore the efficacy of treatment modalities for SFA "de novo" lesions.

METHODS

Eleven treatments for SFA occlusive disease were recognized. We used primary patency and binary restenosis at 12-month follow-up as proxies of efficacy for the treatment of SFA lesions.

RESULTS

A total of 33 studies (66 study arms; 4659 patients) were deemed eligible. In terms of primary patency, odds ratios (ORs) with 95% confidence intervals (CIs) were statistically significantly higher in drug-eluting stent (DES; OR, 10.05; 95% CI, 3.22-31.39), femoropopliteal bypass surgery (BPS; OR, 7.15; 95% CI, 2.27-22.51), covered stent (CS; OR, 3.56; 95% CI, 1.33-9.53), and nitinol stent (NS; OR, 2.83; 95% CI, 1.42-5.51) compared with balloon angioplasty (BA). The rank order from higher to lower primary patency in the multidimensional scaling was DES, BPS, NS, CS, drug-coated balloon, percutaneous transluminal angioplasty with brachytherapy, stainless steel stent, cryoplasty (CR), and BA. Combination therapy of NS with CR and drug-coated balloon were the two most effective treatments, followed by NS, CS, percutaneous transluminal angioplasty with brachytherapy, cutting balloon, stainless steel stent, BA, and CR in terms of multidimensional scaling values for binary restenosis.

CONCLUSIONS

DES has shown encouraging results in terms of primary patency for SFA lesions, whereas BPS still maintains its role as a principal intervention. On the contrary, BA and CR appear to be less effective treatment options.

Antithrombotic Therapy After Peripheral Vascular Intervention

Cardioprotective medications and risk-factor modification are the hallmarks of treatment for all patients with peripheral artery disease (PAD). If symptoms are life-limiting and/or do not respond to conservative treatment, endovascular or surgical revascularization can be considered especially for patients with critical limb ischemia or acute limb ischemia. The rates of peripheral vascular intervention (PVI) have risen dramatically over the past few decades and much of this care have shifted from inpatient hospital settings to outpatient settings and office-based clinics. While PVI rates have surged and technology advancements have dramatically changed the face of PVI, the data behind optimal antithrombotic therapy following PVI is scant. Currently in the USA, most patients are treated with indefinite aspirin therapy and a variable duration of clopidogrel (or other P2Y12 inhibitor)-typically 1 month, 3 months, or indefinite therapy. More observational analyses and randomized clinical trials evaluating clinically relevant outcomes such as cardiovascular morbidity/mortality and the risk of bleeding are needed to guide the optimal role and duration of antithrombotic therapy post-PVI.

Significant variation in P2Y12 inhibitor use after peripheral vascular intervention in Medicare beneficiaries

There is no consensus regarding whether to use antithrombotic medications in patients with peripheral artery disease after lower-extremity peripheral vascular intervention.

OBJECTIVES

The main hypothesis is that significant variation exists regarding use of antithrombotic medications after lower-extremity peripheral vascular intervention. We sought to examine the patterns of postprocedural antithrombotic medication use and associated factors in Medicare patients.

METHODS

We measured rates of P2Y12 inhibitor use after peripheral vascular intervention in a 100% national sample of Medicare beneficiaries with Part D prescription drug coverage. We used logistic regression modeling to examine associations between patient and clinical factors and P2Y12 inhibitor use.

RESULTS

Between 2010 and 2012, a total of 85,830 patients underwent peripheral vascular intervention and had prescription drug claims. Overall, 18.3% of patients were treated with an oral anticoagulant, 19.1% received no P2Y12 inhibitor, 30.8% received a P2Y12 inhibitor before and after the procedure, 6.2% received a P2Y12 inhibitor for up to 30 days after the procedure, and 25.6% received a P2Y12 inhibitor for more than 30 days after the procedure. After adjustment, factors associated with P2Y12 inhibitor use included male sex; black race; history of renal disease, dementia, or heart failure; physician specialty; and clinical setting of the procedure. We observed a strong interaction effect between clinical setting and physician specialty (P < .001).

CONCLUSIONS

One-fifth of patients who underwent lower-extremity peripheral vascular intervention did not fill a prescription for a P2Y12 inhibitor. Patients whose operators were surgeons or radiologists had lower odds of P2Y12 inhibitor use. More research to determine the optimal use and duration of antithrombotic medications after the procedure is warranted.

Lack of Evidence for Dual Antiplatelet Therapy after Endovascular Arterial Procedures: A Meta-analysis

INTRODUCTION

Dual antiplatelet therapy (DAPT) has mainly replaced mono antiplatelet therapy (MAPT) and is recommended after arterial endovascular revascularization. The aim of this meta-analysis was to summarize the available evidence for DAPT after endovascular revascularization throughout the arterial system.

METHODS

A systematic search was performed in Medline, Embase, and the Cochrane Register. Two reviewers independently performed data extraction and quality assessment using the Cochrane Collaboration risk of bias assessment tool. Included in the search were randomized controlled trials (RCTs) comparing DAPT with MAPT after endovascular procedures for the treatment of coronary, carotid, or peripheral artery disease, reporting at least one clinical outcome. Articles were excluded if patients received anticoagulation in addition to antiplatelet therapy in the post-procedural phase. The primary outcome was restenosis or stent thrombosis, and secondary outcomes were major adverse cardiac events (MACE), target lesion revascularization, cerebrovascular accident or transient ischemic attack, bleeding, and death. Meta-analyses of binary outcomes were performed using the random effects model and described as risk ratios (RRs) and 95% confidence intervals (95% CIs). Chi-square tests were used to test for heterogeneity.

RESULTS

Nine articles were included in this study, involving lower limb peripheral arteries (1), carotid arteries (2), and coronary arteries (6). The pooled results of coronary trials showed a RR for restenosis with DAPT of 0.60 (95% CI 0.28-1.31) and for myocardial infarction 0.49 (95% CI 0.12-2.03). In the carotid artery trials the RR for restenosis was 0.22 (95% CI 0.04-1.20) and for peripheral arteries 1.02 (95% CI 0.56-1.82). A meta-analysis of bleeding risk of all the included trials showed a RR of 1.06 (95% CI 0.32-3.52) with DAPT.

CONCLUSION

The available evidence comparing DAPT with MAPT after endovascular arterial revascularization is limited and the majority of trials were conducted in the cardiology field. No significant evidence for superiority of DAPT compared with MAPT was found, but there was also no evidence of an increased bleeding risk with DAPT over MAPT.

Comparison of dual-antiplatelet therapy durations after endovascular revascularization of infrainguinal arteries

BACKGROUND

The optimal dual-antiplatelet therapy (DAPT) duration after endovascular revascularization of infrainguinal arteries is uncertain.

METHODS

This study examines DAPT prescription trends and 12-month major adverse limb events (MALEs; a composite of repeat endovascular or surgical revascularization, acute vessel thrombosis, or amputation of the target limb), major adverse cardiovascular events (MACEs; all-cause mortality, nonfatal myocardial infarction [MI], stroke, or coronary revascularization), fatal bleeding events, and those requiring interruption or discontinuation of DAPT (hemorrhagic complications) for patients enrolled into the Excellence in Peripheral Artery Disease (XLPAD) registry.

RESULTS

Data on 368 patients prescribed antiplatelet therapy were analyzed; 8.2% were prescribed antiplatelet monotherapy, 48.6% DAPT for ≤3 months, and 43.2% for >3 months. Patients in the >3 DAPT prescribed group were older, had preexisting coronary artery disease (CAD), and prior MI (all P < 0.001). Overall MALE in the ≤3 and >3-month DAPT prescribed groups were 22.3% and 23.9%, respectively (P = 0.541). Survival analysis showed significantly higher rates of MACE in patients prescribed >3-month DAPT (17.6% vs. 9.5%; P = 0.019). An "as-treated" analysis excluded 10 patients who were prescribed DAPT for >3 months and revealed similar rates of MALE (24.9% vs. 20.8%; P = 0.386) and MACE (12.2% vs. 14.8%; P = 0.443) in patients receiving ≤3 and >3 DAPT. Hemorrhagic complications were similar across all prescribed and "as-treated" DAPT groups.

CONCLUSIONS

After infrainguinal endovascular procedures, patients with underlying CAD were prescribed longer (>3 months) duration of DAPT and experienced more cardiovascular events compared with those prescribed ≤3 months of DAPT. Adverse limb events were similar in both groups.

Adverse cardiovascular outcomes in relation to suboptimal antithrombotic therapy use in patients undergoing peripheral artery disease angioplasty: lost opportunities?

INTRODUCTION

Current guidelines recommend antithrombotic therapy with either aspirin or clopidogrel for all patients with peripheral arterial disease (PAD). Nevertheless, cardiovascular comorbidities and perceived bleeding risk complicate antithrombotic management of PAD patients. We studied the proportion of patients receiving optimal (guideline-recommended) antithrombotic therapy, and second, assessed the impact of suboptimal antithrombotic therapy use to long-term outcomes of PAD patients.

METHODS

We performed a single centre retrospective analysis of patients with significant PAD, requiring percutaneous intervention. All patients coded as undergoing peripheral artery percutaneous transluminal angioplasty (PTA) between January 2007 and December 2011 were reviewed. Antithrombotic medication on discharge postprocedure was recorded.

RESULTS

Across the study period, 473 patients were coded as having received a PTA, but yet only 336 (71%) had data available for review: 218 (35.2%) male, mean age 73 ± 11 years. Of the whole cohort, 236 (70.2%) were discharged on optimal (guideline-recommended) antithrombotic therapy, 30 (8.9%) were considered 'overtreated' and 70 (20.8%) were undertreated. On multivariate analysis, patients with heart failure were more likely to be undertreated (OR 2.38, 95% CI: 1.15-5.00, p = 0.02) while patient with coronary artery disease were more likely to be overtreated (OR 4.00, 95% CI: 1.61-10.00, p = 0.03). Undertreated patients had an increased risk for all-cause mortality [hazard ratio (HR) 2.96, 95% CI 1.81-4.82: p = 0.00001] and cardiovascular mortality (HR 3.16, 95% CI: 1.49-6.68, p = 0.003).

CONCLUSION

In this single centre cohort of patients undergoing PTA, suboptimal antithrombotic therapy was not uncommon and had a major impact on long-term outcomes, resulting in increased all cause and cardiovascular mortality.

Clopidogrel and 1-Year Freedom From Amputation After Endovascular Lower Extremity Revascularization in the Medicare Population

Objective:

To evaluate freedom from amputation in patients identified utilizing clopidogrel following their lower extremity endovascular revascularization (LER).

Methods:

Patients, 65 years of age and older, undergoing LER were identified from Medicare Provider Analysis and Review and Carrier files utilizing International Classification of Diseases diagnosis and Current Procedural Terminology codes. Postprocedural use of clopidogrel was identified using the National Drug Code directory. Outcomes were evaluated.

Results:

A total of 14 353 patients were identified: 5697 (39.7%) with claudication, 1467 (10.2%) with rest pain, and 7189 (50.1%) with ulceration/tissue loss. In all, 5416 (37.7%) patients were identified using clopidogrel after LER. Overall, patients initiated on clopidogrel had lower amputation rates at 30 days (10.34% vs 14.09%; P < .0001), 90 days (14.05% vs 18.71%; P < .0001), and 1 year (19.68% vs 24.06%; P < .0001).

Conclusion:

Utilization of clopidogrel after LER was associated with lower rates of amputation, yet only 38% of the Medicare population was identified as using clopidogrel. Patients with ulceration and tissue loss benefited the most with significantly greater freedom from amputation and overall survival.

Pharmacology in peripheral arterial disease: what the interventional radiologist needs to know

Peripheral arterial disease (PAD) is a progressive disease with significant morbidity and mortality. Risk factor control, using diet and lifestyle modification, exercise, and pharmacological methods, improves symptoms and reduces associated cardiovascular events in these patients. Antiplatelet agents and anticoagulants may be used to reduce the incidence of acute events related to thrombosis. The armamentarium available for symptom relief and disease modification is discussed. Novel treatments such as therapeutic angiogenesis are in their evolutionary phase with promising preclinical data.

Patients carrying CYP2C19 loss of function alleles have a reduced response to clopidogrel therapy and a greater risk of in-stent restenosis after endovascular treatment of lower extremity peripheral arterial disease

OBJECTIVE

This study evaluated the relationship between the cytochrome P450 (CYP) 2C19 genotype and the antiplatelet effect of clopidogrel therapy and investigated whether genotyping can predict the risk of ischemic events after endovascular treatment (ET) of lower extremity peripheral arterial disease.

METHODS

From January 2011 to July 2012, 120 consecutive patients with arteriosclerosis obliterans (TransAtlantic Inter-Society Consensus for the Management of Peripheral Arterial Disease [TASC II] A-C) in the superficial femoral artery were included in a prospectively maintained database. Patients received 75 mg clopidogrel and 100 mg aspirin daily for at least 5 days before TaqMan (Life Technologies, Grand Island, NY) of CYP2C19 single-nucleotide polymorphisms and thromboelastography of the clopidogrel response. ET was subsequently performed, and follow-up evaluations, including duplex ultrasound imaging and ankle-brachial index assessment, were performed at 1, 3, 6, and 12 months after ET. During the follow-up, stent patency was assessed by ultrasound imaging, computed tomography angiography, or digital subtraction angiography.

RESULTS

A total of 74 ET procedures were performed. Fifty of the enrolled patients (41.7%) completed the follow-up examinations and were included in the analysis. The mean duration of follow-up was 9.8 ± 2.1 months (range, 1-30 months). Carriers of at least one CYP2C19 loss-of-function (LOF) allele had a diminished pharmacodynamic response to clopidogrel (51.6 ± 20.1 vs. 39.8 ± 15.2 for patients without and with LOF alleles, respectively; P = .022). Carriers of one LOF allele had an increased incidence of ischemic events compared with patients without any LOF alleles (59.0% vs. 20.8%, respectively; P = .008). This trend was even more evident in patients with two LOF alleles compared with patients with no LOF alleles (100% vs. 20.8% ischemic events; P = .002). The cumulative primary patency rate at 12 months was 56.0%, with significant differences between groups (73.1% vs. 34.6% in patients without and with LOF alleles, respectively; P = .0.006). CYP2C19 LOF carrier status was associated with an increased rate of primary end points (P = .007). On the basis of their adenosine diphosphate-induced platelet aggregation, patients with high platelet reactivity had a significantly higher risk of ischemic events (P = .012). CYP2C19 genotypic classification (adjusted hazard ratio, 2.688; 95% confidence interval, 1.366-5.288; P = .004) and history of smoking (adjusted hazard ratio, 2.430; 95% confidence interval, 1.024-5.765; P = .044) were independent risk factors for ischemic events.

CONCLUSIONS

CYP2C19 LOF alleles were associated with a diminished platelet response to clopidogrel treatment. Patients carrying CYP2C19 LOF alleles who are treated with clopidogrel may trend toward a poor prognosis after ET.

Antithrombotic Strategies in Endovascular Interventions: Current Status and Future Directions

Despite increasing numbers of endovascular interventions to treat arterial and venous disease, scant level 1 evidence is available regarding the role of antithrombotic and antiplatelet therapy in patients undergoing these procedures. The current practice in this regard is heterogeneous and has mainly been driven by data from coronary artery disease and percutaneous coronary intervention. This article discusses the role of antithrombotic and antiplatelet agents for endovascular intervention.