Association of the Prognosis of Ankle-brachial Index Improvement One Year Following Endovascular Therapy in Patients with Peripheral Artery Disease: Data from the I-PAD NAGANO Registry

Objective Despite reports on the effects of ankle-brachial index (ABI) improvement following endovascular therapy (EVT) on the limb prognosis, studies evaluating cardiovascular events are limited. We investigated whether or not ABI improvement 1 year following EVT was associated with cardiovascular events. Methods The I-PAD NAGANO registry is an observational multicenter cohort study that enrolled 337 patients with peripheral artery disease (PAD) who underwent EVT between August 2015 and July 2016. From this cohort, we identified 232 patients whose ABI data 1 year following EVT were available, after excluding patients with critical limb ischemia. We divided the patients into two groups according to the degree of ABI improvement 1 year following EVT (ΔABI) - the ΔABI <0.15 group and the ΔABI ≥0.15 group - and compared the outcomes. The primary endpoint was major adverse cardiovascular events (MACEs), including all - cause death, myocardial infarction (MI), and stroke. The secondary endpoints were major adverse limb events (MALEs), defined as a composite of target lesion revascularization and major amputation, all - cause death, MI, and stroke. The median follow-up period was 3.3 years. Results The incidence of MACEs was significantly higher in the ΔABI <0.15 group than in the ΔABI ≥0.15 group (ΔABI <0.15 vs. ΔABI ≥0.15, 25.8% vs. 11.9%, log-rank p=0.036), as was the incidence of stroke (14.1% vs. 2.2%, log-rank p=0.016). A Cox regression analysis revealed that ΔABI ≥0.15 was significantly associated with fewer MACEs (hazard ratio 0.38, 95% confidence interval 0.17-0.83, p=0.016). Conclusion An increase in ABI ≥0.15 at 1 year following EVT was a predictor of reduced MACEs.