Abstract 10531: Reactive Hyperemia Index and Coronary Plaque in Asymptomatic Adults - Insights From the Miami Heart Study at Baptist Health South Florida

Objective: We aimed to evaluate the associations between the reactive hyperemia index (RHI), a non-invasive estimate of endothelial function, and coronary artery plaque presence and features on coronary computed tomography angiography (CCTA); and whether these associations differ by sex. Methods: Data from Miami Heart Study, an ongoing, prospective US cohort of individuals free of clinical ASCVD. A total of 2,097 participants underwent assessment of both RHI using EndoPAT® (abnormal RHI defined as <1.67) and a CCTA scan. We computed the unadjusted prevalence of 4 plaque outcomes (any coronary plaque on CCTA, CAC score >0, maximal coronary stenosis ≥50%, and presence of ≥1 high-risk plaque features) among individuals with and without abnormal RHI; overall and by sex. Multivariable logistic regression models were used to investigate the association between RHI and the outcomes adjusting for confounders, overall and by sex. Results: Of the 2,097 participants, mean age was 53 years, 50% were women, and 15% had abnormal RHI. Mean age was 54±7 vs. 53±7 years for normal vs. abnormal RHI, respectively, and 17% men vs 13% women had abnormal RHI. In unadjusted analyses, abnormal RHI was not associated with a significant higher prevalence of any of the study outcomes ( Figure Panel A ; all P >0.05). Adjusting for sociodemographics, no statistically significant associations were observed between abnormal RHI and any of the coronary plaque features evaluated ( Panel B ). Similar observations were noted further adjusting for other risk factors. There was no evidence of interaction by sex in any of the associations (P for interaction: all >0.05). Conclusions: In the Miami Heart Study, abnormal RHI measured using EndoPAT was not associated with coronary plaque in either women nor men. Our findings suggest that this measurement may be suboptimal in the assessment of endothelial function, and not informative in predicting the presence of subclinical coronary atherosclerosis.