Effect of Warfarin Anticoagulation on Below-Knee Polytetrafluoroethylene Graft Patency

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.

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.

The Impact of Antithrombotic Regimens on Clinical Outcomes After Endovascular Intervention and Bypass Surgery for Infrapopliteal Artery Disease

Endovascular intervention and bypass surgery are the main options of treatments for infrapopliteal artery disease. Although post-intervention treatment with antiplatelet (AP) and/or anticoagulant (AC) drugs has reduced morbidity and mortality rates from cardiovascular complications; the ideal antithrombotic treatment regimen is unknown. The aim of this review was to compare the efficacy and safety of various anticoagulation and/or AP therapy regimens in patients undergoing below-knee endovascular treatment for infrapopliteal artery disease. We reviewed published literature in PubMed and Google Scholar, and Cochrane, evaluating efficacy and safety outcomes after antithrombotic treatment following endovascular intervention or bypass surgery in patients with infrapopliteal artery disease. We extracted relevant efficacy and safety data with related statistics from each study. We found that AP treatment should be administered to patients receiving endovascular therapy or bypass. We did not find superior effects for dual AP treatment (DAPT) over mono-AP therapy (MAPT) for endovascular intervention or bypass surgery with venous graft, suggesting that MAPT suffices for these groups. Also, aspirin + clopidogrel was effective over aspirin alone for prosthetic, but not venous graft, albeit higher non-severe bleeding incidences, suggesting a potential benefit of this regime for below-knee prosthetic graft. AP + AC yielded superior results compared to AP following endovascular procedure and bypass surgery, suggesting the potential benefit of this regime in the absence of contraindications. More prospective studies with large number of patients are warranted to identify the best treatment for infrapopliteal artery diseases.

Analysis of Thirty-Day Readmission after Infrainguinal Bypass

BACKGROUND

The Vascular Study Group of New England (VSGNE) conducted a pilot study evaluating the feasibility of 30-day data collection in patients undergoing infrainguinal bypass (INFRA) which was subsequently expanded to include a limited number of additional sites within the Vascular Quality Initiative (VQI). The purpose of our study was to use these data to evaluate the incidence of 30-day readmission after infrainguinal bypass. A secondary goal of the study was to perform a critical appraisal of the data elements and definitions in the 30-day dataset.

METHODS

All infrainguinal bypass procedures performed during the pilot study period (7/2008 and 4/2016) were identified and merged with a dataset containing the 30-day data. Incidence and types of readmission were assessed. The primary endpoint was 30-day readmission, defined as any hospital readmission within 30 days of index operation; unplanned 30-day readmission was the secondary endpoint. Covariates tested for association with the primary and secondary endpoints included patient demographics, comorbidities, procedural, and postoperative characteristics. Variables significant on univariate screen (P < 0.2) were evaluated with logistic regression to identify independent determinants.

RESULTS

Of 9,847 infrainguinal bypass patients, 5,842 (59%) patients were identified with 30-day data, and 907 (16%) were readmitted within 30 days. Of readmissions, 675 (85%) were unplanned. Potentially modifiable independent determinants of any 30-day readmission included 30-day surgical site infection (SSI) (odds ratio [OR]: 10, 95% confidence interval [CI]: 8.2-12, P < 0.0001), postoperative acute kidney injury (OR: 1.7, 95% CI: 1.2-2.5, P = 0.002), and discharge anticoagulation (OR: 1.2, 95% CI: 1.04-1.5; P = 0.02). Predictors of unplanned 30-day readmission were very similar but identified in-hospital major amputation as an additional independent predictor (OR: 2.8, 95% CI: 1.6-4.9, P = 0.0002).

CONCLUSIONS

This study demonstrates the interest in, and value of, 30-day data collection in VSGNE/VQI and documents the frequency of readmission after infrainguinal bypass. Readmission within 30 days is strongly associated with SSI, stressing the importance of efforts to decrease this complication. Given that many other predictors are unmodifiable, 30-day readmission is only appropriate as a quality metric if it is risk adjusted using large, real-world datasets such as VQI. Lessons learned from this analysis can be used to select optimal 30-day data elements.