Abstract P184: Racial Differences In Mental Stress-induced Transient Endothelial Dysfunction And Its Association With Cardiovascular Outcomes

Background: An established link exists between acute mental stress and the development of transient endothelial dysfunction (TED) as assessed by brachial artery flow-mediated vasodilation (FMD). Black individuals have a high burden of cardiovascular (CV) risk factors and social disadvantages, which may result in adverse vascular responses to stress. We investigated differences in TED with mental stress in Black and non-Black individuals with coronary artery disease (CAD), and whether TED is associated with CV outcomes in both groups. Methods: We enrolled 812 patients with stable CAD between June 2011 and March 2016 and followed them through February 2020. Study participants were subjected to a public-speaking mental stress task and FMD (derived from % vasodilation with brachial artery hyperemia testing) was assessed by ultrasound before and 30 minutes after mental stress. TED was defined as a lower post-stress FMD than pre-stress FMD. We compared pre-stress FMD, post-stress FMD, and TED between Black and non-Black participants. In both groups, we examined the association of TED with an adjudicated composite end point of CV death and myocardial infarction (MI) after adjusting for demographic, clinical, and socioeconomic factors. Both first and recurring events were counted and multivariable models for repeated events were used for analysis. Results: The mean (SD) age was 59 (10) years, and 328 (40%) were Black. Pre-stress FMD was lower in Black than non-Black participants [3.7 (2.8) vs. 4.9 (3.8) p<0.001], and significantly declined with mental stress in both groups. TED occurred more often in Black (76%) than non-Black patients (67%), age- and sex-adjusted OR, 1.6, 95% CI, 1.4-1.7). Race related differences in TED persisted after adjustment for demographic factors, CAD risk factors and medications (Black vs. non-Black OR, 1.6, 95% CI, 1.5-1.7). After further adjusting for socioeconomic indicators (education, income, and employment status), TED remained elevated in Black patients (OR, 1.4 (95% CI, 1.3-1.6). Over a median (interquartile range) follow-up period of 75 (65-82) months, 142 (18%) patients had at least one event. Development of TED with mental stress was associated with an increased risk for the study outcome both in Black (age- and sex-adjusted HR, 3.0; 95% CI, 1.3-6.8) and non-Black participants (HR, 1.7, 95% CI, 0.96-3.0), p=0.26 for interaction. Adjustment for demographic, clinical and socioeconomic factors did not diminish these associations. Conclusions: Among CAD patients, Black individuals are more likely than non-Black individuals to develop endothelial dysfunction with mental stress, which in turn is associated with an increased risk of adverse cardiovascular events. Endothelial dysfunction in response to psychological stress may represent an important mechanism for the disproportionate risk of adverse CV outcomes in Black patients.