Association of Baseline Cardio-Ankle Vascular Index with 12-month Change in Arterial Stiffness in Patients with Coronary Artery Disease: An Exploratory Single-Center Longitudinal Analysis

Background: The cardio-ankle vascular index (CAVI) reflects arterial stiffness and is associated with the severity of coronary artery disease (CAD). Short-term change in CAVI in patients with angiographically documented CAD is poorly described. We explored whether baseline CAVI was associated with its 12-month change. Methods: This exploratory secondary analysis used data from a previously published single-center study, extended with 12-month follow-up. Clinically stable patients with at least 50% coronary stenosis on invasive angiography and paired CAVI measurements were included. Change in the mean of right and left CAVI (ΔCAVI-mean) was the 12-month value minus the baseline value; positive values indicate greater stiffness, and ΔCAVI-mean ≥ +0.5 defined worsening. Non-worsening was analyzed by logistic regression; post hoc analyses estimated the change expected from regression to the mean. Results: Of 157 patients, 33 (21.0%) worsened. CAVI-mean was 9.20 ± 0.80 at baseline and 9.15 ± 0.76 at 12 months (r = 0.43). Baseline CAVI-mean ≥ 9.0 was associated with non-worsening (odds ratio adjusted for age and sex 8.10, 95% CI 3.35– 19.58). ΔCAVI-mean differed by − 0.81 (95% CI − 1.08 to − 0.54) between patients with baseline CAVI-mean ≥ 9.0 and those below 9.0; regression to the mean alone predicted a difference of − 0.74. ΔCAVI-mean was not related to the average of the two measurements (Oldham’s method: r = − 0.05; p = 0.54). Conclusion: In this selected single-center CAD cohort, baseline CAVI-mean ≥ 9.0 was associated with lower odds of CAVI worsening over 12 months. The association was of the size expected from regression to the mean and should not be interpreted as a biological effect. The worsening threshold is not clinically validated and no clinical outcomes were assessed. Studies of change in CAVI need repeated measurements, continuous modeling, and validation in larger cohorts with clinical outcomes. Keywords: cardio-ankle vascular index, arterial stiffness, coronary artery disease, longitudinal change, regression to the mean