Cardio-Ankle Vascular Index is Independently Associated with Future Cardiovascular Events in Outpatients with Metabolic Disorders

Aim: We investigated whether cardio-ankle vascular index (CAVI), an arterial stiffness marker, independently predicts future cardiovascular events in subjects with metabolic disorders. Methods: 1562 outpatients underwent CAVI between April 2004 and March 2006 at Toho University, Sakura Medical Center in Chiba, Japan. Patients who already had cardiovascular events at baseline, patients with low ankle brachial index (<0.9), and patients with atrial fibrillation were excluded. After exclusion, 1080 subjects with metabolic disorders including diabetes mellitus, hypertension and dyslipidemia were screened and followed prospectively. Results: Eventually, 1003 subjects (92.9% of 1,080 subjects) followed until March 2012 (follow-up duration 6.7+/-1.6 years) were analyzed. During the observation period, 90 subjects had new-onset myocardial infarction or angina pectoris confirmed by angiography. All subjects were stratified into quartiles by baseline CAVI (Q1: CAVI <= 8.27, Q2: CAVI 8.28-9.19, Q3: CAVI 9.20-10.08, Q4: CAVI >= 10.09). Age, male ratio and future cardiovascular events increased as CAVI quartile became higher. In Cox proportional hazards regression analysis, the factors independently associated with higher risk of future cardiovascular events were every 1.0 increment of CAVI [hazard ratio (HR) 1.126, p=0.039], male gender (HR 2.276, p=0.001), smoking (HR 1.846, p=0.007), diabetes mellitus (HR 1.702, p=0.020), and hypertension (HR 1.682, p=0.023). Conclusion: In individuals with metabolic disorders, CAVI was a predictor of future cardiovascular events, independent of traditional coronary risk factors. CAVI is a potentially valuable tool to identify persons likely to benefit from more intensive therapeutic approaches.