Improved Prediction of Cardiovascular Events Using Serial Cardio-Ankle Vascular Index (CAVI) Measurements: A 10-Year Prospective Cohort Study

Abstract

Background: Most studies evaluating the cardio-ankle vascular index (CAVI) as a marker of arterial stiffness are cross-sectional, limiting insights into long-term vascular changes. We investigated whether serial CAVI measurements improve the prediction of cardiovascular (CV) events beyond a single baseline value. Methods: The Electricity Generating Authority of Thailand (EGAT) study is a prospective cohort with 5-year follow-up intervals. Participants with prior coronary artery disease (CAD) or stroke were excluded. Demographic, clinical, laboratory data, medication use, and CAVI were collected. Serial CAVI was analyzed as a time-varying covariate in Cox proportional hazards models, incorporating baseline, 5-year, and 10-year measurements. The primary composite CV outcomes comprised CAD, stroke, or CV death. Cox proportional hazards models assessed associations between baseline or serial CAVI and CV outcomes, adjusted for conventional risk factors. Results: Among 3913 participants (mean age 49.0 ± 10.8 years; 73.4% male; BMI 24.3 ± 3.6 kg/m²), mean CAVI increased from 7.7 ± 1.1 to 8.2 ± 1.3 over 10 years (p < 0.001). During a median follow-up of 9.1 ± 3.1 years, 0.8% experienced composite CV events. Serial CAVI was independently associated with CV outcomes (HR 1.47; 95% CI 1.06–2.03; p = 0.019), whereas baseline CAVI was not (HR 1.14; 95% CI 0.93–1.40; p = 0.22). Model indices (ΔAIC = 37.1; ΔBIC = 32.7) supported superior predictive performance for serial CAVI. Conclusion: Serial CAVI measurements better predict long-term CV events than a single baseline value. Longitudinal CAVI monitoring may enhance CV risk stratification and support preventive cardiovascular care.