Ultrasound-detected tibial artery calcification as a marker of cardiovascular and lower-limb risk in asymptomatic patients with type-2 diabetes

Background: Medial arterial calcification (MAC) is a vascular disease distinct from atherosclerosis. Recently, several studies have demonstrated that MAC is an important marker of cardiovascular events. We aim to assess the presence of MAC during ultrasound screening of lower-limb vasculature and its association with both cardiovascular (CV) and lower-limb events in patients with type-2 diabetes. Methods: A retrospective cohort study was conducted on 1119 patients with type-2 diabetes free from CV disease. A CV work-up, including vascular ultrasound, was performed for each patient. The presence of MAC was assessed on posterior tibial arteries and ankle–brachial index (ABI) was measured. Major acute CV events (MACEs) and lower-limb events (MALEs) were recorded as a composite endpoint for a 5-year period. Results: We identified MAC among 212 (18.9%) patients. The independent determinants of MAC were age and diabetic retinopathy. Over a period of 5 years, 125 MACEs and 22 MALEs occurred. MAC was significantly associated with the composite outcome MACE + MALE (HR = 1.94; 95% CI: 1.23, 3.08, p = 0.005) or with MACE (HR = 1.85; 95% CI: 1.16, 2.95, p = 0.010). Adjusted for ABI and diabetic foot wound, MAC remained a determinant of MALE (HR = 5.49; 95% CI: 2.19, 13.76, p < 0.001). Considering each ABI group, MAC was associated with both MACE and MALE in the normal ABI group. Conclusions: Ultrasound-detected MAC on tibial arteries seems to be a determinant of both CV and lower-limb events, independent from ABI. MAC helps to refine the CV risk in patients with normal ABI.