Incompressible ankle arteries predict increased morbidity and mortality in patients with an elevated ankle brachial index.

OBJECTIVES: Patients with an elevated ankle brachial index (ABI) > 1.3 have a high burden of disease and poorer outcome compared to patients with a lower ABI. Previously differences between patients with ABI > 1.3 have not been studied in detail. The aim of this study was to analyze the morbidity and mortality of patients with ABI > 1.3.

METHODS: ABI measurements were performed in the vascular laboratory of Turku university hospital 2011-2013. Patients with ABI>1.3 in at least one lower limb were included in the study and divided into 3 groups: At least one lower limb ABI 1.3-2.5 but both limbs <2.5 (group 1), one limb ABI ≥2.5 (group 2), both limbs ABI ≥ 2.5 (group 3).

RESULTS: 534 patients were included in the study. The patients in groups 2 and 3 were more often female ( p < .001), older ( p < .001), had more diabetes ( p = .013), coronary artery disease ( p = .001) and chronic heart ( p = .010) and kidney failure ( p = .013) compared to patients in group 1. The survival of patients in group 2 and 3 was significantly poorer compared to the patients in group 1 (HR1.6, 95% CI 1.2-2.2, p = .002 and 1.7, 95% CI 1.2-2.3, p < .001, respectively). Overall and cardiovascular mortality was higher in groups 2 and 3 than group 1.39.5% of patients with incompressible ankle arteries (ABI ≥ 2.5) in both lower limbs had toe pressure (TP) <50 mmHg and a poorer survival compared to patients with a higher TP.

CONCLUSIONS: Patients with incompressible ankle arteries have significantly higher overall and cardiovascular mortality and a greater burden of disease compared to the patients with a measurable yet abnormally high ABI. TP is a useful diagnostic tool when ABI is immeasurably high. All patients with ABI > 1.3 should be considered as high cardiovascular risk patients.