Bleeding and thrombotic outcomes associated with postoperative use of direct oral anticoagulants after open peripheral artery bypass procedures

Direct oral anticoagulants over warfarin at discharge associated with improved survival and patency in infra-geniculate bypasses with prosthetic conduits

OBJECTIVE

There is no consensus on the optimal anticoagulant regimen following lower extremity bypass. Historically, warfarin has been utilized for prosthetic or compromised vein bypasses. Direct-acting oral anticoagulants (DOACs) are increasingly replacing warfarin in this context, but their efficacy in bypass preservation has not been well-studied. Recent studies have shown that DOACs may improve outcomes following bypasses; however, it is unclear if this is dependent upon type of bypass conduit. The goal of this study was to evaluate whether a difference exists between vein and prosthetic infra-geniculate bypasses outcomes based on the anticoagulant utilized on discharge, warfarin or DOAC.

METHODS

The Vascular Quality Initiative infra-inguinal bypass database was queried for all patients who underwent an infra-geniculate bypass and were anticoagulation-naive at baseline but were discharged on either warfarin or DOACs. A survival analysis was performed for patients up to 1 year to determine whether the choice of discharge anticoagulation was associated with differences between those with vein vs prosthetic conduits in overall survival, primary patency, risk of amputation, or risk of major adverse limb events (MALE). A multivariable Cox proportional hazards analysis was performed to control for differences in baseline demographic factors between the groups.

RESULTS

During the study period (2003-2020), 57,887 patients underwent infra-geniculate bypass. Of these, 3230 (5.5%) were anticoagulated on discharge. There was a similar distribution of anticoagulation between vein (n = 1659; 51.4%) and prosthetic conduits (n = 1571; 48.6%). Thirty-two percent were discharged on DOACs, and 68.0% were discharged on warfarin. For prosthetic conduits, being discharged on a DOAC was associated with improved outcomes on univariate and multivariable analyses revealing lower risk of overall mortality (hazard ratio [HR], 0.61; 95% confidence interval [CI], 0.41-0.93; P = .021), loss of primary patency (HR, 0.70; 95% CI, 0.55-0.89; P = .003), risk of amputation (HR, 0.71; 95% CI, 0.54-0.93; P = .013), and risk of MALE (HR, 0.80; 95% CI, 0.64-1.00; P = .048). Patients with a vein bypass had improved univariate outcomes for survival and primary patency; however, with multivariable analysis, there were no significant differences in outcomes between DOAC and warfarin.

CONCLUSIONS

Anticoagulation-naive patients who underwent an infra-geniculate prosthetic bypass had higher rates of overall survival, bypass patency, amputation-free survival, and freedom from MALE when discharged on a DOAC compared with warfarin. Those with vein bypasses had similar outcomes regardless of the choice of anticoagulation.

Rivaroxaban in patients with symptomatic peripheral artery disease after lower extremity bypass surgery with venous and prosthetic conduits

BACKGROUND

Patients with peripheral artery disease (PAD) requiring lower extremity revascularization (LER) have a high risk of adverse limb and cardiovascular events. The results from the VOYAGER PAD (efficacy and safety of rivaroxaban in reducing the risk of major thrombotic vascular events in subjects with symptomatic peripheral artery disease undergoing peripheral revascularization procedures of the lower extremities) trial have demonstrated that rivaroxaban significantly reduced this risk with an overall favorable net benefit for patients undergoing surgical revascularization. However, the efficacy and safety for those treated by surgical bypass, including stratification by bypass conduit (venous or prosthetic), has not yet been described.

METHODS

In the VOYAGER PAD trial, patients who had undergone surgical and endovascular infrainguinal LER to treat PAD were randomized to rivaroxaban 2.5 mg twice daily or placebo on top of background antiplatelet therapy (aspirin 100 mg to be used in all and clopidogrel in some at the treating physician's discretion) and followed up for a median of 28 months. The primary end point was a composite of acute limb ischemia, major amputation of vascular etiology, myocardial infarction, ischemic stroke, and cardiovascular death. The principal safety outcome was major bleeding using the TIMI (thrombolysis in myocardial infarction) scale. The index procedure details, including conduit type (venous vs prosthetic), were collected at baseline.

RESULTS

Among 6564 randomized patients, 2185 (33%) had undergone surgical LER. Of these 2185 patients, surgical bypass had been performed for 1448 (66%), using a prosthetic conduit for 773 patients (53%) and venous conduit for 646 patients (45%). Adjusting for the baseline differences and anatomic factors, the risk of unplanned limb revascularization in the placebo arm was 2.5-fold higher for those receiving a prosthetic conduit vs a venous conduit (adjusted hazard ratio [HR], 2.53; 95% confidence interval [CI], 1.65-3.90; P < .001), and the risk of acute limb ischemia was three times greater (adjusted HR, 3.07; 95% CI, 1.84-5.11; P < .001). The use of rivaroxaban reduced the primary outcome for the patients treated with bypass surgery (HR, 0.78; 95% CI, 0.62-0.98), with consistent benefits for those receiving venous (HR, 0.66; 95% CI, 0.49-0.96) and prosthetic (HR, 0.87; 95% CI, 0.66-1.15) conduits (P_interaction = .254). In the overall trial, major bleeding using the TIMI scale was increased with rivaroxaban. However, the numbers for those treated with bypass surgery were low (five with rivaroxaban vs nine with placebo; HR, 0.55; 95% CI, 0.18-1.65) and not powered to show statistical significance.

CONCLUSIONS

Surgical bypass with a prosthetic conduit was associated with significantly higher rates of major adverse limb events relative to venous conduits even after adjustment for patient and anatomic characteristics. Adding rivaroxaban 2.5 mg twice daily to aspirin or dual antiplatelet therapy significantly reduced this risk, with an increase in the bleeding risk, but had a favorable benefit risk for patients treated with bypass surgery, regardless of conduit type. Rivaroxaban should be considered after lower extremity bypass for symptomatic PAD to reduce ischemic complications of the heart, limb, and brain.

Direct Oral Anticoagulants as the First Choice of Anticoagulation for Patients with Peripheral Artery Disease to Prevent Adverse Vascular Events: A Systematic Review and Meta-Analysis

The best method of anticoagulation for patients with peripheral artery disease (PAD) is still a topic of interest for physicians. We conducted a meta-analysis to compare the effects of direct oral anticoagulants (DOACs) with those of vitamin-K-antagonist (VKA) anticoagulants in patients with peripheral artery disease. Five databases (Medline (via PubMed), EMBASE, Scopus, Web of Science, and CENTRAL) were searched systematically for studies comparing the effects of the two types of anticoagulants in patients with PAD, with an emphasis on lower-limb outcomes, cardiovascular events, and mortality. In PAD patients with concomitant non-valvular atrial fibrillation (NVAF), the use of DOACs significantly reduced the risk of major adverse limb events (HR = 0.58, 95% CI, 0.39-0.86, p < 0.01), stroke/systemic embolism (HR 0.76; 95% CI 0.61-0.95; p < 0.01), and all-cause mortality (HR 0.78; 95% CI 0.66-0.92; p < 0.01) compared with warfarin, but showed similar risks of MI (HR = 0.81, 95% CI, 0.59-1.11, p = 0.2) and cardiovascular mortality (HR = 0.77, 95% CI, 0.58-1.02, p = 0.07). Rivaroxaban at higher doses significantly increased the risk of major bleeding (HR = 1.16, 95% CI, 1.07-1.25, p < 0.01). We found no significant difference in terms of revascularization (OR = 1.49, 95% CI, 0.79-2.79, p = 0.14) in PAD patients in whom a poor distal runoff was the reason for the anticoagulation. DOACs have lower rates of major limb events, stroke, and mortality than VKAs in PAD patients with atrial fibrillation. Rivaroxaban at higher doses increased the risk of major bleeding compared with other DOAC drugs. More high-quality studies are needed to determine the most appropriate anticoagulation regimen for patients with lower-limb atherosclerosis.

Use of direct-acting oral anticoagulants associated with improved survival and bypass graft patency compared with warfarin after infrageniculate bypass

OBJECTIVE

No consensus has yet been reached regarding the optimal antiplatelet and anticoagulant regimen for patients after lower extremity bypass. Usually, patients who have undergone below-the-knee bypass will begin oral anticoagulation therapy. Historically, the bypass has been with prosthetic conduits and the anticoagulation therapy has been warfarin. However, the use of direct-acting oral anticoagulants (DOACs) has been increasing owing to their relative ease of dosing. The goal of the present study was to evaluate whether a difference exists in the postoperative outcomes for patients who have undergone infrageniculate bypass stratified by the use of on DOACs vs warfarin.

METHODS

The Vascular Quality Initiative infrainguinal bypass database was queried for all patients who had undergone infrageniculate bypass, been anticoagulation naive at baseline, and been discharged with anticoagulation therapy. A survival analysis was performed for patients for ≤2 years postoperatively to determine whether discharge with warfarin vs DOACs was associated with differences in overall mortality, loss of primary patency, risk of amputation, and risk of major adverse limb events (MALE). A multivariable Cox proportional hazards analysis was performed to control for differences in the baseline demographic factors between the two groups.

RESULTS

During the study period (2007-2020) 57,887 patients had undergone infrageniculate bypass. Of these patients, 2786 had been anticoagulation naive and discharged with either warfarin (n = 1889) or DOACs (n = 897). Discharge with a DOAC was associated with a lower risk of overall mortality (hazard ratio [HR], 0.62; 95% confidence interval [CI], 0.47-0.83; P = .001), loss of primary patency (HR, 0.74; 95% CI, 0.62-0.87; P < .001), risk of amputation (HR, 0.70; 95% CI, 0.57-0.86; P = .001), and risk of MALE (HR, 0.83; 95% CI, 0.71-0.97; P = .017).

CONCLUSIONS

Anticoagulation-naive patients who had undergone infrageniculate bypass had had higher rates of overall survival, bypass patency, amputation-free survival, and freedom from MALE when discharged with a DOAC than with warfarin.

Effect of Direct Oral Anticoagulants versus Warfarin on Patency in High-Risk Bypass Patients

OBJECTIVES

The use of warfarin for anticoagulation in thromboembolic disease has been the mainstay of treatment. Direct oral anticoagulants (DOACs) have demonstrated equivalent anticoagulant effects, without increased bleeding risks or need for frequent monitoring. However, the role of DOACs remains unclear in the setting of replacing warfarin for high-risk peripheral artery disease (PAD) interventions. The purpose of this study is to evaluate the efficacy of DOACs compared to warfarin during the postoperative period in patients that underwent a lower extremity high risk bypass (HRB).

METHODS

The study is a single institution, retrospective review of all lower extremity HRBs be-tween January 2012 and June 2021, who were previously placed on or started on anticoagulation with a DOAC or warfarin. The HRB group included all patients undergoing femoral to above or below knee bypass with an adjunct procedure, or below knee bypass with synthetic or composite vein conduit. All demographics, preoperative factors, and complications were evaluated with respect to DOAC versus warfarin.

RESULTS

A total of 44 patients (28 males; average age 68.8 ± 10.9) underwent a HRB during the study period. There were no significant differences in demographics and preoperative characteristics between the two groups. Among patient comorbidities, coronary artery disease was found to be significantly higher in patients on DOACs (p=0.03). The 12-month primary patency rate was 83.3% vs 57.1%, for DOAC vs warfarin respectively (p=0.03). Multivariate analyses revealed that <30-day reinterventions contribute to 12-month patency (p=0.02).

CONCLUSION

Patients who underwent lower extremity HRB with postoperative DOAC appeared to exhibit higher graft patency rates than those who were placed on warfarin. Due to their low incidence of undesirable side effects and the lack of frequent monitoring, DOACs could be considered a safe alternative to warfarin in the postoperative period for patients with HRB.

Effect of postoperative antithrombotic therapy on lower extremity outcomes after infrapopliteal bypass for chronic limb-threatening ischemia

OBJECTIVE

Although the current guidelines have recommended single antiplatelet therapy (SAPT) for patients undergoing revascularization for chronic limb-threatening ischemia (CLTI), antithrombotic management has varied by patient and provider. Our aim was to examine the effects of different postoperative antithrombotic regimens on 3-year clinical outcomes after infrapopliteal bypass for CLTI.

METHODS

We identified patients who had undergone infrapopliteal bypass for CLTI in the Vascular Quality Initiative (VQI) registry from 2003 to 2017 with linkage to Medicare claims for long-term outcomes. We divided the patients into three cohorts according to the discharge antithrombotic regimen: SAPT (aspirin or clopidogrel), dual antiplatelet therapy (DAPT; aspirin and clopidogrel), or anticoagulation (AC) plus any antiplatelet (AP) agent. To reduce selection bias, we restricted the analysis cohorts to patients treated by providers who discharged >50% of patients with each antithrombotic regimen. Our primary outcome was 3-year major adverse limb events (MALE; major amputation or reintervention). The secondary outcomes included 3-year major amputation, reintervention, and mortality. We used Kaplan-Meier and Cox regression analyses to assess these outcomes stratified by antithrombotic regimen and adjusted for demographic, comorbid, clinical, and operative differences between the treatment groups with clustering at the center level.

RESULTS

Among 1812 patients (median follow-up, >2 years), 693 (38%) were discharged with SAPT, 544 (30%) with DAPT, and 575 (32%) with AC+AP. At 3 years, the MALE rates were 75% with DAPT, 74% with AC+AP, and 68% with SAPT. In adjusted analyses with SAPT as the reference group, no differences were found in 3-year MALE with DAPT (adjusted hazard ratio [aHR], 1.0; 95% confidence interval [CI], 0.85-1.3; P = .71) or AC+AP (aHR, 1.1; 95% CI, 0.96-1.3; P = .14). Across the treatment groups, we also found no differences in the individual end points of 3-year major amputation (DAPT: aHR, 0.98; 95% CI, 0.72-1.3; AC+AP: aHR, 1.3; 95% CI, 0.96-1.7), reintervention (DAPT: aHR, 1.0; 95% CI, 0.84-1.3; AC+AP: aHR, 1.1; 95% CI, 0.96-1.3), or mortality (DAPT: aHR, 1.1; 95% CI, 0.88-1.4; AC+AP: aHR, 0.95; 95% CI, 0.74-1.2). In a sensitivity analysis evaluating patients treated by providers who discharged >60%, >70%, or >80% of patients with these regimens, the association between antithrombotic regimen and MALE was unchanged.

CONCLUSIONS

Compared with SAPT, DAPT and anticoagulation therapy were not associated with improved outcomes among Medicare beneficiaries who had undergone infrapopliteal bypass for CLTI at VQI participating centers. These findings support current guidelines recommending SAPT after lower extremity bypass and suggest that the routine use of DAPT or anticoagulation therapy might not provide clinical benefit in this high-risk, elderly population. However, further evaluation of the risks and benefits of various antithrombotic regimens in relevant subgroups is warranted.

Antithrombotic Treatment for Peripheral Arterial Occlusive Disease

BACKGROUND

Patients with peripheral arterial occlusive disease (PAOD) are at elevated risk for cardiovascular events and vascular events affecting the limbs. The goals of antithrombotic treatment are to keep vessels open after revascularization, to prevent cardiovascular events, and to lessen the frequency of peripheral ischemia and of amputation.

METHODS

This review is based on pertinent publications retrieved by a selective literature search, with particular attention to meta-analyses, randomized controlled trials, and the German and European angiological guidelines.

RESULTS

Diabetes mellitus and nicotine abuse are the main risk factors for lower limb PAOD. The evidence for the efficacy and safety of antithrombotic treatment in patients with PAOD is limited, in particular, after surgical or endovascular revascularization. Intensifying antithrombotic treatment with stronger antiplatelet therapy (APT), dual antiplatelet therapy (DAPT), or antiplatelet therapy combined with anticoagulation lowers the rate of peripheral revascularization (relative risk [RR] 0.89; 95% confidence interval [0.83; 0.94]), amputation (RR 0.63; [0.46; 0.86]), and stroke (RR 0.82; [0.70; 0.97]) but raises the risk of bleeding (RR 1.23; [1.04; 1.44]). Predictors for peripheral vascular events include critical limb ischemia and having previously undergone a revascularization procedure or an amputation.

CONCLUSION

Antiplatelet therapy should only be intensified for a limited time, or if the risk of ischemia is high. Before and during intensified antiplatelet therapy, the risk of bleeding should be assessed and weighed against the risk of ischemia. No validated score is available to estimate the risk of hemorrhagic complications in patients with PAOD. New antithrombotic therapies should not be used indiscriminately, but should rather be reserved for selected groups of patients.