Predictive Value of Abnormal and Borderline Ankle-Brachial Index for Coronary Re-Intervention and Mortality in Patients with Coronary Artery Disease: An Observational Cohort Study

PURPOSE: This study aimed to investigate the abnormal and borderline ABIs for predicting coronary re-intervention and mortality in patients with coronary artery disease (CAD). MATERIALS AND METHODS: Data from a previous study were obtained and used to investigate the prevalence of peripheral arterial disease among Korean patients with CAD (n=285) in 2010. All patients underwent follow-up coronary angiography as scheduled (asymptomatic: 2-, 5-, and 7-month intervals) or as clinically indicated (symptomatic). RESULTS: In total, 33 patients had an abnormal ABI (ab-ABI: <1.0 or >1.4), and 252 had a normal ABI (nl-ABI: 1.0≤ABI≤1.4). The mean follow-up was 47 months. The mortality was significantly higher in the ab-ABI group than in the nl-ABI group (18.2% vs. 6.7%, P=0.0233). MACEs were significantly more common in the ab-ABI group (60.6% vs. 34.5%, P=0. 0036). Moreover, the ab-ABI group had a greater CAD progression than the nl-ABI group (48.5% vs. 31.3%, P=0.0496). The incidence of clinically indicated coronary re-intervention was significantly higher in the ab-ABI group than in the nl-ABI group (33.3% vs. 13.1%, P=0.0025). After adjusting for age, diabetes, dyslipidemia, dialysis, smoking, and obesity, the incidence of clinically indicated re-intervention was significantly higher in the ab-ABI group than in the nl-ABI group (HR, 2.80; 95% CI, 1.24 to 6.34). CONCLUSION: Abnormal and borderline ABI significantly increased the incidence of clinically indicated coronary revascularization and all-cause mortality during a 4-year follow-up among patients with CAD. Hence, ABI could be used to stratify extremely high-risk patients with CAD who may require aggressive surveillance or treatment.