The impact of current smoking on outcomes after infrainguinal bypass for claudication

Although smoking cessation is a benchmark of medical management of intermittent claudication, many patients require further revascularization. Currently, revascularization among smokers is a controversial topic, and practice patterns differ institutionally, regionally, and nationally. Patients who smoke at the time of revascularization are thought to have a poor prognosis, but data on this topic are limited. The purpose of this study was to evaluate the impact of smoking on outcomes after infrainguinal bypass for claudication.

Data from the national Vascular Quality Initiative from 2004 to 2014 were used to identify infrainguinal bypasses performed for claudication. Patients were categorized as former smokers (quit >1 year before intervention) and current smokers (smoking within 1 year of intervention). Demographic and comorbid differences of categorical variables were assessed. Significant predictors were included in adjusted Cox proportional hazards models to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) by smoking status for outcomes of major adverse limb event (MALE), amputation-free survival, limb loss, death, and MALE or death. Cumulative incidence curves were created using competing risks modeling.

We identified 2913 patients (25% female, 9% black) undergoing incident infrainguinal bypass grafting for claudication. There were 1437 current smokers and 1476 former smokers in our study. Current smoking status was a significant predictor of MALE (HR, 1.27; 95% CI, 1.00-1.60; P = .048) and MALE or death (HR, 1.22; 95% CI, 1.03-1.44; P = .02). Other factors found to be independently associated with poor outcomes in adjusted models included black race, below-knee bypass grafting, use of prosthetic conduit, and dialysis dependence.

Current smokers undergoing an infrainguinal bypass procedure for claudication experienced more MALEs than former smokers did. Future studies with longer term follow-up should address limitations of this study by identifying a data source with long-term follow-up examining the relationship of smoking exposure (pack history and duration) with outcomes.