Risk stratification in critical limb ischemia: derivation and validation of a model to predict amputation-free survival using multicenter surgical outcomes data.
ABSTRACT: Patients with critical limb ischemia (CLI) are a heterogeneous population with respect to risk for mortality and limb loss, complicating clinical decision-making. Endovascular options, compared with bypass, offer a tradeoff between reduced procedural risk and inferior durability. Risk stratified data predictive of amputation-free survival (AFS) may improve clinical decision making and allow for better assessment of new technology in the CLI population.This was a retrospective analysis of prospectively collected data from patients who underwent infrainguinal vein bypass surgery for CLI. Two datasets were used: the PREVENT III randomized trial (n = 1404) and a multicenter registry (n = 716) from three distinct vascular centers (two academic, one community-based). The PREVENT III cohort was randomly assigned to a derivation set (n = 953) and to a validation set (n = 451). The primary endpoint was AFS. Predictors of AFS identified on univariate screen (inclusion threshold, P < .20) were included in a stepwise selection Cox model. The resulting five significant predictors were assigned an integer score to stratify patients into three risk groups. The prediction rule was internally validated in the PREVENT III validation set and externally validated in the multicenter cohort.The estimated 1-year AFS in the derivation, internal validation, and external validation sets were 76.3%, 72.5%, and 77.0%, respectively. In the derivation set, dialysis (hazard ratio [HR] 2.81, P < .0001), tissue loss (HR 2.22, P =.0004), age >or=75 (HR 1.64, P = .001), hematocrit or=8 [8.8% of cohort]). Stratification of the patients, in each dataset, according to risk category yielded three significantly different Kaplan-Meier estimates for 1-year AFS (86%, 73%, and 45% for low, medium, and high risk groups, respectively). For a given risk category, the AFS estimate was consistent between the derivation and validation sets.Among patients selected to undergo surgical bypass for infrainguinal disease, this parsimonious risk stratification model reliably identified a category of CLI patients with a >50% chance of death or major amputation at 1 year. Calculation of a "PIII risk score" may be useful for surgical decision making and for clinical trial designs in the CLI population.
Project description:Despite poor long-term patency, acceptable limb salvage has been reported with cryopreserved saphenous vein bypass (CVB) for various indications. However, utility of CVB in patients with critical limb ischemia (CLI) remains undefined. The purpose of this analysis was to determine the role of CVB in CLI patients and to identify predictors of successful outcomes.A retrospective review of all lower extremity bypass (LEB) procedures at a single institution was completed, and CVB in CLI patients were further analyzed. The primary end point was amputation-free survival. Secondary end points included primary patency and limb salvage. Life tables were used to estimate occurrence of end points. Cox regression analysis was used to determine predictors of limb salvage.From 2000 to 2012, 1059 patients underwent LEB for various indications, of whom 81 received CVB for either ischemic rest pain or tissue loss. Mean age (± standard deviation) was 66 ± 10 years (male, 51%; diabetes, 51%; hemodialysis dependence, 12%), and 73% (n = 59) had history of failed ipsilateral LEB or endovascular intervention. None had sufficient autogenous conduit for even composite vein bypass. Infrainguinal CVB (infrapopliteal target, 96%; n = 78) was completed for multiple indications including Rutherford class 4 (42%; n = 34), class 5 (40%; n = 32), and class 6 (18%; n = 15). Eleven (14%) had CLI and concomitant graft infection (n = 8) or acute on chronic ischemia (n = 3). Intraoperative adjuncts (eg, profundaplasty, suprainguinal stent or bypass) were completed in 49% (n = 40) of cases. Complications occurred in 36% (n = 29), with 30-day mortality of 4% (n = 3). Median follow-up for CLI patients was 11.8 (interquartile range, 0.4-28.4) months with corresponding 1- and 3-year actuarial estimated survival (± standard error mean) of 84% ± 4% and 62% ± 6%. Primary patency of CVB for CLI was 27% ± 6% and 17% ± 6% at 1 and 3 years, respectively. Amputation-free survival was 43% ± 6% and 23% ± 6% at 1 and 3 years, respectively, and significantly higher for rest pain (59% ± 9%, 36% ± 10%) compared with tissue loss (31% ± 7%, 14% ± 7%; log-rank, P = .04). Freedom from major amputation after CVB for CLI was 57% ± 6% and 43% ± 7% at 1 and 3 years. Multivariable predictors of limb salvage for the CVB CLI cohort included postoperative warfarin (hazard ratio [HR], 0.4; 95% confidence interval [CI], 0.2-0.8), dyslipidemia (HR, 0.4; 95% CI, 0.2-0.9), and rest pain (HR, 0.4; 95% CI, 0.2-0.9). Predictors of major amputation included graft infection (HR, 3.1; 95% CI, 1.1-9.0).In CLI patients with no autologous conduit and prior failed infrainguinal bypass, CVB outcomes are disappointing. CVB performs best in patients with rest pain, particularly those who can be anticoagulated with warfarin. However, it may be an acceptable option in patients with minor tissue loss or concurrent graft infection, but consideration should be weighed against the known natural history of nonrevascularized CLI and nonbiologic conduit alternatives, given potential cost implications.
Project description:Although statin therapy has been linked to fewer short-term complications after infrainguinal bypass, its effect on long-term survival remains unclear. We therefore examined associations between statin use and long-term mortality, graft occlusion, and amputation after infrainguinal bypass.We used the Vascular Study Group of New England registry to study 2067 patients (71% male; mean age, 67 ± 11 years; 67% with critical limb ischemia [CLI]) who underwent infrainguinal bypass from 2003 to 2011. Of these, 1537 (74%) were on statins perioperatively and at 1-year follow-up, and 530 received no statin. We examined crude, adjusted, and propensity-matched rates of 5-year surviva1, 1-year amputation, graft occlusion, and perioperative myocardial infarction.Patients taking statins at the time of surgery and at the 1-year follow-up were more likely to have coronary disease (38% vs 22%; P < .001), diabetes (51% vs 36%; P < .001), hypertension (89% vs 77%; P < .001), and prior revascularization procedures (50% vs 38%; P < .001). Despite higher comorbidity burdens, long-term survival was better for patients taking statins in crude (risk ratio [RR], 0.7; P < .001), adjusted (hazard ratio, 0.7; P = .001), and propensity-matched analyses (hazard ratio, 0.7; P = .03). In subgroup analysis, a survival advantage was evident in patients on statins with CLI (5-year survival rate, 63% vs 54%; log-rank, P = .01) but not claudication (5-year survival rate, 84% vs 80%; log-rank, P = .59). Statin therapy was not associated with 1-year rates of major amputation (12% vs 11%; P = .84) or graft occlusion (20% vs 18%; P = .58) in CLI patients. Perioperative myocardial infarction occurred more frequently in patients on a statin in crude analysis (RR, 2.2; P = .01) but not in the matched cohort (RR, 1.9; P = .17).Statin therapy is associated with a 5-year survival benefit after infrainguinal bypass in patients with CLI. However, 1-year limb-related outcomes were not influenced by statin use in our large observational cohort of patients undergoing revascularization in New England.
Project description:Critical limb ischemia (CLI) is a major cause of limb loss and mortality among patients with advanced peripheral artery disease. Our objective was to evaluate the gender-specific differences in patient characteristics and clinical outcomes among patients with CLI. We performed a retrospective analysis of 97 women and 122 men presenting with CLI who underwent angiography from 2006 to 2010. Baseline demographics, procedural details, and lesion characteristics were assessed for each patient. Kaplan-Meier analysis was used to assess long-term patient and lesion-level outcomes. Cox proportional hazard modeling was used to evaluate the relationship between gender and major adverse cardiovascular events (MACE). Compared to men, women were less likely to have a history of coronary artery disease (39% vs 54%, p = 0.02) or diabetes (57% vs 70%, p = 0.05) but had similar baseline medical therapy. At angiography, women were more likely to have significant femoropopliteal (77% vs 67%, p = 0.02) and multi-level infrainguinal disease (63% vs 51%, p = 0.02). Women were also more likely to undergo multi-vessel percutaneous intervention (69% vs 55%, p = 0.05), but had similar rates of limb salvage after percutaneous intervention or surgical bypass (HR 0.94 [95% CI 0.45-1.94], p = 0.9). During follow-up, women had higher rates of subsequent major adverse cardiovascular events (HR 1.63 [95% CI 1.01-2.63], p = 0.04). In conclusion, women with CLI are more likely to present with femoropopliteal and multi-level infrainguinal disease. Despite similar rates of limb salvage, women with CLI have an increased rate of subsequent major adverse cardiovascular events.
Project description:Unplanned hospital readmissions following surgical interventions are associated with adverse events and contribute to increasing health care costs. Despite numerous studies defining risk factors following lower extremity bypass surgery, evidence regarding readmission after endovascular interventions is limited. This study aimed to identify predictors of 30-day unplanned readmission following infrainguinal endovascular interventions.We identified all patients undergoing an infrainguinal endovascular intervention in the targeted vascular module of the American College of Surgeons National Surgical Quality Improvement Program between 2012 and 2014. Perioperative outcomes were stratified by symptom status (chronic limb-threatening ischemia [CLI] vs claudication). Patients who died during index admission and those who remained in the hospital after 30 days were excluded. Indications for unplanned readmission related to the index procedure were evaluated. Multivariable logistic regression was used to identify preoperative and in-hospital (during index admission) risk factors of 30-day unplanned readmission.There were 4449 patients who underwent infrainguinal endovascular intervention, of whom 2802 (63%) had CLI (66% tissue loss) and 1647 (37%) had claudication. The unplanned readmission rates for CLI and claudication patients were 16% (n = 447) and 6.5% (n = 107), respectively. Mortality after index admission was higher for readmitted patients compared with those not readmitted (CLI, 3.4% vs 0.7% [P < .001]; claudication, 2.8% vs 0.1% [P < .01]). Approximately 50% of all unplanned readmissions were related to the index procedure. Among CLI patients, the most common indication for readmission related to the index procedure was wound or infection related (42%), whereas patients with claudication were mainly readmitted for recurrent symptoms of peripheral vascular disease (28%). In patients with CLI, predictors of unplanned readmission included diabetes (odds ratio, 1.3; 95% confidence interval, 1.01-1.6), congestive heart failure (1.6; 1.1-2.5), renal insufficiency (1.7; 1.3-2.2), preoperative dialysis (1.4; 1.02-1.9), tibial angioplasty/stenting (1.3; 1.04-1.6), in-hospital bleeding (1.9; 1.04-3.5), in-hospital unplanned return to the operating room (1.9; 1.1-3.5), and discharge other than to home (1.5; 1.1-2.0). Risk factors for those with claudication were dependent functional status (3.5; 1.4-8.7), smoking (1.6; 1.02-2.5), diabetes (1.5; 1.01-2.3), preoperative dialysis (3.6; 1.6-8.3), procedure time exceeding 120 minutes (1.8; 1.1-2.7), in-hospital bleeding (2.9; 1.2-7.4), and in-hospital unplanned return to the operating room (3.4; 1.2-9.4).Unplanned readmission after endovascular treatment is relatively common, especially in patients with CLI, and is associated with substantially increased mortality. Awareness of these risk factors will help providers identify patients at high risk who may benefit from early surveillance, and prophylactic measures focused on decreasing postoperative complications may reduce the rate of readmission.
Project description:Infrainguinal bypass (IB) surgery is an effective means of improving arterial circulation to the lower extremity for patients with critical limb ischemia (CLI). However, wound complications (WC) of the surgical incision following IB can impart significant morbidity.A retrospective analysis of WC from the 1404 patients enrolled in a multicenter clinical trial of vein bypass grafting for CLI was performed. Univariate and multivariable regression models were used to determine WC predictors and associated outcomes, including graft patency, limb salvage, quality of life (QoL), resource utilization (RU), and mortality.A total of 543 (39%) patients developed a reported WC within 30 days of surgery, with infections (284, 52%) and hematoma/hemorrhage (121, 22%) being the most common type. Postoperative anticoagulation (odds ratio [OR], 1.554; 95% confidence interval [CI] 1.202 to 2.009; P = .0008) and female gender (OR, 1.376; 95% CI, 1.076 to 1.757; P = .0108) were independent factors associated with WC. Primary, primary-assisted, and secondary graft patency rates were not influenced by the presence of WC; though, patients with WC were at increased risk for limb loss (hazard ratio [HR], 1.511; 95% CI 1.096 to 2.079; P = .0116) and higher mortality (HR, 1.449; 95% CI 1.098 to 1.912; P = .0089). WC was not significantly associated with lower QoL at 3 months (4.67 vs 4.79, P = .1947) and 12 months (5.02 vs 5.13, P = .2806). However, the subset of patients with serious WC (SWC) demonstrated significantly lower QoL at 3 months compared with patients without WC, (4.43 vs 4.79, respectively, P = .0166), though this difference was not seen at 12 months (4.94 vs 5.13, P = .2411). Patients with WC had higher RU than patients who did not have WC. Mean index length of hospital stay (LOS) was 2.3 days longer, mean cumulative 1-year LOS was 8.1 days longer, and mean number of hospitalizations was 0.5 occurrences greater for patients with WC compared with patients without WC (all P < .0001).WC is a frequent complication of IB for CLI, associated with increased risk for major amputation, mortality, and greater RU. Further detailed investigation into the link between female gender and oral anticoagulation use with WC may help identify causes of WC and perhaps prevent or lessen their occurrence.
Project description:Our objective was to analyze periprocedural and 1-year outcomes of peripheral endovascular intervention (PVI) for critical limb ischemia (CLI).We reviewed 1244 patients undergoing 1414 PVIs for CLI (rest pain, 29%; tissue loss, 71%) within the Vascular Study Group of New England (VSGNE) from January 2010 to December 2011. Overall survival (OS), amputation-free survival (AFS), and freedom from major amputation at 1 year were analyzed using the Kaplan-Meier method. Cox proportional hazards models were used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs).The number of arteries treated during each procedure were 1 (49%), 2 (35%), 3 (12%), and ?4 (5%). Target arterial segments and TransAtlantic Inter-Society Consensus classifications were aortoiliac, 27% (A, 48%; B, 28%; C, 12%; and D, 12%); femoral-popliteal, 48% (A, 29%; B, 34%; C, 20%; and D, 17%); and infrapopliteal, 25% (A, 17%; B, 14%; C, 25%; D, 44%). Technical success was 92%. Complications included access site hematoma (5.0%), occlusion (0.3%), and distal embolization (2.4%). Mortality and major amputation rates were 2.8% and 2.2% at 30 days, respectively. Overall percutaneous or open reintervention rate was 8.0% during the first year. At 1-year, OS, AFS, and freedom from major amputation were 87%, 87%, and 94% for patients with rest pain and 80%, 71%, and 81% for patients with tissue loss. Independent predictors of reduced 1-year OS (C index = .74) included dialysis (HR, 3.8; 95% CI, 2.8-5.1; P < .01), emergency procedure (HR, 2.5; 95% CI, 1.0-6.2; P = .05), age >80 years (HR, 2.2; 95% CI, 1.7-2.8; P < .01), not living at home preoperatively (HR, 2.0; 95% CI, 1.4-2.8; P < .01), creatinine >1.8 mg/dL (HR, 1.9; 95% CI, 1.3-2.8; P < .01), congestive heart failure (HR, 1.7; 95% CI, 1.3-2.2; P < .01), and chronic ?-blocker use (HR, 1.4; 95% CI, 1.0-1.9; P = .03), whereas independent preoperative ambulation (HR, 0.7; 95% CI, 0.6-0.9; P = .014) was protective. Independent predictors of major amputation (C index = .69) at 1 year included dialysis (HR, 2.7; 95% CI, 1.6-4.5; P < .01), tissue loss (HR, 2.0; 95% CI, 1.1-3.7; P = .02), prior major contralateral amputation (HR, 2.0; 95% CI, 1.1-3.5; P = .02), non-Caucasian race (HR, 1.7; 95% CI, 1.0-2.9; P = .045), and male gender (HR, 1.6; 95% CI, 1.1-2.6; P = .03), whereas smoking (HR, .60; 95% CI, 0.4-1.0; P = .042) was protective.Survival and major amputation after PVI for CLI are associated with different patient characteristics. Dialysis dependence is a common predictor that portends especially poor outcomes. These data may facilitate efforts to improve patient selection and, after further validation, enable risk-adjusted outcome reporting for CLI patients undergoing PVI.
Project description:Although open surgical bypass remains the standard revascularization strategy for patients with critical limb ischemia (CLI), many centers now perform peripheral endovascular intervention (PVI) as the first-line treatment for these patients. We sought to determine the effect of a prior ipsilateral PVI (iPVI) on the outcome of subsequent lower extremity bypass (LEB) in patients with CLI.A retrospective cohort analysis of all patients undergoing infrainguinal LEB between 2003 and 2009 within hospitals comprising the Vascular Study Group of New England (VSGNE) was performed. Primary study endpoints were major amputation and graft occlusion at 1 year postoperatively. Secondary outcomes included in-hospital major adverse events (MAE), 1-year mortality, and composite 1-year major adverse limb events (MALE). Event rates were determined using life table analyses and comparisons were performed using the log-rank test. Multivariate predictors were determined using a Cox proportional hazards model with multilevel hierarchical adjustment.Of 1880 LEBs performed, 32% (n = 603) had a prior infrainguinal revascularization procedure (iPVI, 7%; ipsilateral bypass, 15%; contralateral PVI, 3%; contralateral bypass, 17%). Patients with prior iPVI, compared with those without a prior iPVI, were more likely to be women (32 vs 41%; P = .04), less likely to have tissue loss (52% vs 63%; P = .02), more likely to require arm vein conduit (16% vs 5%; P = .001), and more likely to be on statin (71% vs 54%; P = .01) and beta blocker therapy (92% vs 81%; P = .01) at the time of their bypass procedure. Other demographic factors were similar between these groups. Prior PVI or bypass did not alter 30-day MAE and 1-year mortality after the index bypass. In contrast, 1-year major amputation and 1-year graft occlusion rates were significantly higher in patients who had prior iPVI than those without (31% vs 20%; P = .046 and 28% vs 18%; P = .009), similar to patients who had a prior ipsilateral bypass (1 year major amputation, 29% vs 20%; P = .022; 1 year graft occlusion, 33% vs 18%; P = .001). Independent multivariate predictors of higher 1-year amputation and graft occlusion rates were prior iPVI, prior ipsilateral bypass, dialysis dependence, prosthetic conduit and distal (tibial and pedal) bypass target.Prior iPVI is highly predictive for poor outcome in patients undergoing LEB for CLI with higher 1-year amputation and graft occlusion rates than those without prior revascularization, similar to prior ipsilateral bypass These findings provide information, which may help with the complex decisions surrounding revascularization options in patients with CLI.
Project description:Isolated common femoral endarterectomy was recently reported to have a 30-day mortality of 3.4%. The effect of adjunctive femoral endarterectomy at the time of lower extremity bypass is not well described, and therefore, the purpose of this study was to determine its associated perioperative and long-term risk.Vascular Study Group of New England registry data were used to identify patients undergoing initial lower extremity bypass from 2003 to 2015. After univariate analysis, multivariable logistic regression was used to identify the independent association of endarterectomy with adverse perioperative events. Kaplan-Meier and Cox hazard models were used for the 1-year analysis.After exclusions, 4496 patients were identified as undergoing infrainguinal bypass (33% with endarterectomy). There was no difference in the proportion with chronic limb-threatening ischemia (CLI; 68% vs 67%; P = .24) or tissue loss of those with CLI (65% vs 63%; P = .34) between the adjunctive endarterectomy group and bypass alone, respectively. Patients undergoing adjunctive endarterectomy were older (mean 68 years vs 67 years; P = .02), more likely white (95% vs 93%; P = .02), smokers (91% vs 87%; P = .001), and more often had prior coronary artery bypass grafting/percutaneous coronary intervention (34% vs 31%; P = .02). The endarterectomy cohort had similar 30-day mortality (CLI: 2.6% vs 2.9%; P = .60; claudication: 0.2% vs 0.4%; P = 1.0) despite a longer operative time (median, 268 minutes vs 210 minutes; P < .001) and increased blood loss (median, 250 mL vs 180 mL; P < .001). Patients with CLI undergoing adjunctive endarterectomy had more in-hospital myocardial infarctions (MIs; 6.2% vs 3.8%; P = .003) and transfusions (11% vs 6.8%; P < .001). At 1-year, this group had a suggestion of improved freedom from major amputation (91% vs 87%; P = .049) and amputation-free survival (80% vs 76%; P = .03) that did not reach significance after adjustment. For patients with claudication and adjunctive endarterectomy, rates of MI (2.4% vs 0.9%; P = .02), renal dysfunction (3.6% vs 1.4%; P = .01), surgical site infection (SSI; 5.0% vs 2.6%; P = .02), and transfusion (4.6% vs 1.8%; P = .002) were higher. After adjustment, all patients undergoing adjunctive endarterectomy were at increased risk of MI (odds ratio [OR], 1.6; 95% confidence interval [CI], 1.1-2.2), SSI (OR, 1.5; 95% CI, 1.1-2.0), and bleeding requiring transfusion (OR, 1.8; 95% CI, 1.4-2.3). There were no differences in 1-year survival for CLI or claudication groups and no difference in all 1-year end points for patients with claudication.Adjunctive femoral endarterectomy with bypass is safe, with no difference in perioperative or 1-year mortality compared with bypass. However, surgeons should be aware that adjunctive endarterectomy is associated with an increased risk of bleeding, SSI, and MI, likely from these patients' disease burden and presumed more extensive atherosclerosis.
Project description:OBJECTIVE:Lower extremity bypass (LEB) has traditionally been the "gold standard" in the treatment of critical limb ischemia (CLI). Infrainguinal endovascular intervention (IEI) has become more commonly performed than LEB, but comparative outcomes are limited. We sought to compare rates of major adverse limb events (MALEs) and major adverse cardiovascular events (MACEs) after LEB and IEI in a propensity score-matched, national cohort of patients with CLI. METHODS:The National Surgical Quality Improvement Program (NSQIP) vascular targeted files (2011-2014) for LEB and IEI were merged. CLI patients were identified by ischemic rest pain or tissue loss. Patients were matched on a 1:1 basis for propensity to undergo LEB or IEI. Primary outcomes were 30-day MALEs and MACEs. Within the propensity-matched cohort, multivariate logistic regression was used to identify independent predictors of MALEs and MACEs. RESULTS:A total of 13,294 LEBs and IEIs were identified, with 8066 cases performed for CLI. Propensity matching identified 3848 cases (1924 per group). There were no differences in preoperative variables between the propensity-matched LEB and IEI groups (all P > .05). At 30 days, rates of MALEs were significantly lower in the LEB group (9.2% LEB vs IEI 12.2%; P = .003). On multivariate logistic regression, bypass with single-segment saphenous vein vs IEI (odds ratio [OR], 0.7; 95% confidence interval [CI], 0.54-0.92; P = .01), bypass with alternative conduit (prosthetic, spliced vein, or composite) vs IEI (OR, 0.7; 95% CI, 0.56-0.98; P = .04), antiplatelet therapy (OR, 0.8; 95% CI, 0.58-1.00; P = .049), and statin therapy (OR, 0.8; 95% CI, 0.62-0.99; P = .04) were protective against MALEs, whereas infrageniculate intervention (OR, 1.4; 95% CI, 1.09-1.72; P = .01) and a history of prior bypass of the same arterial segment (OR, 1.8; 95% CI, 1.41-2.41; P <. 0001) were predictive. Rates of 30-day MACEs were not significantly different (4.9% LEB vs 3.7% IEI; P = .07) between the groups. Independent predictors of MACEs included age (OR, 1.02; 95% CI, 1.01-1.04; P = .01), steroid use (OR, 1.8; 95% CI, 1.08-2.99; P = .03), congestive heart failure (OR, 1.7; 95% CI, 1.00-1.96; P = .02), beta blocker use (OR, 1.6; 95% CI, 1.09-1.43; P = .01), dialysis (OR, 2.3; 95% CI, 1.55-3.45; P < .0001), totally dependent functional status (OR, 3.1; 95% CI, 1.25-7.58; P = .02), and suboptimal conduit for LEB compared with IEI (OR, 1.6; 95% CI, 1.08-2.36; P = .02). CONCLUSIONS:Within this large, propensity-matched, national cohort, LEB predicted lower risk-adjusted 30-day MALE rate compared with IEI. Furthermore, there was no difference in 30-day MACE rate between the groups despite higher inherent risk with open surgical procedures. Therefore, this study supports the effectiveness and primacy of LEB for revascularization in CLI.
Project description:Therapeutic anticoagulation (AC) is used clinically for prolongation of infrainguinal bypass patency, but evidence for the efficacy of this practice is conflicting. The objective of our study was to determine the association of AC with bypass graft primary patency.Clinical and comorbid data of patients undergoing infrainguinal bypass grafts to a below-knee target with at least 1 year of follow-up performed from 2003 to 2015 were obtained from the Society for Vascular Surgery Vascular Quality Initiative. Inverse propensity of treatment-weighted Cox regression was used to assess the effect of AC on patency in the total cohort while adjusting for clinical, operative, and comorbid differences between treatment groups. Subgroup analyses of distal targets and conduit type were performed. Perioperative complications were analyzed using propensity-weighted logistic regression.We identified 7612 bypass grafts with intact 1-year follow-up information from 2003 to 2015. The mean age was 67.5 ± 11.2 years; 30.5% (n = 2320) were female, and 28.6% (n = 2165) were discharged on therapeutic AC. The anticoagulated group had a higher rate of tibial, ankle, and pedal targets (52.1% [n = 1127] vs 47.6% [n = 2269]; P < .001), had a greater use of non-single-segment vein conduits (44.3% [n = 951] vs 26.5% [n = 1426]; P < .001), and was more likely to have had a previous ipsilateral bypass (27.2% [n = 589] vs 14.7% [n = 794]; P < .001) or stent (25.4% [n = 550] vs 20.9% [n = 1130]; P < .001). Estimated unadjusted primary patency was 70.8% ± 0.6% at 1 year and lower for anticoagulated bypasses (66.9% ± 1.2% vs 72.4% ± 0.7%; P < .001). Propensity-weighted analysis showed no significant association of AC with primary patency in the overall cohort (hazard ratio [HR], 0.98; 95% confidence interval [CI], 0.86-1.11; P = .8) but demonstrated a trend toward improvement of primary patency in those with a non-single-segment vein conduit to a below-knee popliteal target (HR, 0.85; 95% CI, 0.80-1.02; P = .09). AC was associated with significantly improved secondary patency in those with prosthetic bypass grafts (HR, 0.77; 95% CI, 0.62-0.96; P = .02) or prosthetic bypasses to an infrapopliteal target (HR, 0.72; 95% CI, 0.54-0.97; P = .02). Odds of postoperative wound complications were significantly higher in those receiving AC (odds ratio, 1.33; 95% CI, 1.11-1.61; P = .002).This study does not demonstrate a significant impact of therapeutic AC on primary patency for infrainguinal bypass grafts. Treatment with AC may benefit secondary patency in those with a prosthetic bypass, especially to an infrapopliteal target, but at an increased risk of postoperative wound complications.