Abstract P366: Repeatability of Cardio-Ankle Vascular Index in Morbidly Obese Individuals

Abstract

Background: The AHA 2016 Statement for arterial stiffness evaluation introduced several novel parameters. Cardio-ankle vascular index (CAVI) is one of them and has a unique property of being largely independent of blood pressure (BP) at the time of examination. The repeatability of CAVI has been confirmed in healthy population but not in morbidly obese individuals. Methods: We investigated 76 participants (mean age 44 years, and mean BMI 48 kg/m 2 [ranged from 36-70]) in the BARI-Heart Study, who underwent 2 standardized visits (1-10 months apart) before bariatric surgery. CAVI was measured twice 5-minute apart at each visit using oscillometric device VaSera VS-1500 (Fukuda Denshi, Tokyo, Japan) at a supine position. We calculated intra-class correlation coefficient (ICC), minimal detectable change (MDC 95 ) and minimal detectable difference (MDD) using a nested random-effects analysis of variance model for CAVI. As a contrast, we also calculated these repeatability statistics for brachial and ankle BP measured using the same device when CAVI was measured. Results: At the first visit, average CAVI was 6.2 (SD 1.1) and average brachial systolic and diastolic BP was 146 mmHg (SD 13) and 86 mmHg (SD 7). For short-term repeatability in 5 minutes at the first visit, the ICCs were very high for both CAVI and brachial and ankle BPs (all with ICC ≥ 0.82 bilaterally). When we observed longer term repeatability over several months, the ICCs were fair for BPs (ranged from 0.42-0.57) but remained very high for CAVI with ≥0.72 for both sides. The MDC 95 between repeated measures within an individual across two visits was 1.6-1.7 for CAVI and 15-35 mmHg for BP parameters. In this scenario, the MDD for two independent samples of 100 per group was ~0.5 for CAVI and 4-8 mmHg for BP parameters. Conclusion: The short- and longer-term repeatability of CAVI was overall good even among morbidly obese individuals. Our results suggest that a longitudinal change of CAVI by 1.6-1.7 indicates a change beyond the measurement error.