Ultrasound Detection of Below-the-Knee Medial Arterial Calcifications in Asymptomatic Patients Is an Early Negative Predictor of Major Adverse Cardiovascular Events

Background: Medial arterial calcification (MAC) is a vascular disorder that affects the arterial media layer. It represents a predictor of major adverse limb events in patients affected by diabetes mellitus (DM). This single-center retrospective observational study investigates whether ultrasound (US) detection of MAC in below-the-knee (BTK) vessels represents a negative predictor of major adverse cardiovascular events (MACE) in asymptomatic patients. Methods: In 2019, 584 patients, referred to the Vascular Surgery Unit for lower limb US, were examined by the same operator, who assessed the presence of BTK MAC. The primary outcome was the rate of MACE during a 5-year follow-up period. The secondary outcomes included the development of peripheral arterial disease (PAD), the overall survival rates, lower limb revascularizations, and major amputations. Results: MAC in BTK vessels was highlighted in 239 patients (MAC+) who exhibited a younger age (p < 0.001), DM (p < 0.001), and chronic kidney disease (CKD) (p = 0.048). The 345 subjects without MAC (MAC−) showed prior myocardial infarction (p < 0.001), stroke (p = 0.034), and smoking habits (p < 0.001). After propensity score matching, the MAC+ group presented a higher risk of MACE (HR: 1.84; CI: 1.01–3.38; p = 0.047) during a median follow-up of 57 months. Age (HR: 1.06; CI: 1.01–1.12) and MAC (HR: 1.22; CI: 1.06–1.57) were independently associated with MACE. New diagnoses of PAD mainly occurred in the MAC− group (p < 0.001). No differences were observed in major amputations, revascularization procedures, or overall survival rates. Conclusions: Ultrasound detection of BTK MAC was associated with the presence of DM and CKD and with a 1.8-fold increased risk of developing a MACE within 5 years in asymptomatic patients.