Evaluation of Risk Factors for Limb-Specific Peripheral Vascular Events in Patients With Peripheral Artery Disease: A Post Hoc Analysis of the SEASON Prospective Observational Study.

ABSTRACT

Surveillance of cardiovascular Events in Antiplatelet-treated arterioSclerosis Obliterans patients in JapaN (SEASON) is a 2-year, prospective, real-world, registry study conducted in Japan from 2009 to 2013. This post hoc analysis evaluated risk factors for limb ischemia in patients with peripheral arterial disease (PAD) and ankle-brachial index (ABI) <0.90. Vascular events were adjudicated by an Efficacy Endpoint Review Committee. Cox regression identified predictors of limb-specific peripheral vascular events (amputation, development of critical limb ischemia, and acute limb ischemia). Patients (n = 6565) were stratified according to ABI normal (≥1.0; n = 1300), borderline (0.90 ≤ ABI ≤ 1.0; n = 776), and abnormal (<0.90; n = 4489). Compared to normal ABI, patients with ABI <0.90 had a significantly higher risk of any vascular event, all-cause death, and any limb-specific peripheral vascular event. Risk factors for limb-specific vascular events included history of lower extremity revascularization/amputation (adjusted hazard ratio 2.18; 95% confidence interval [CI] 1.49-3.20), chronic kidney disease (2.00; 1.33-3.00), diabetes (1.71; 1.16-2.52), and ABI <0.4 (4.45; 2.62-7.55) or <0.7 (1.78; 1.15-2.76). These findings from a Japanese real-world population confirm the increased vascular risk of patients with PAD and ABI <0.90 and identified risk factors for limb-specific peripheral vascular events.