Abstract
BACKGROUND: Microvascular measures of vascular dysfunction during acute mental stress may be important determinants of major adverse cardiovascular events (MACE), especially among younger and middle-aged women survivors of an acute myocardial infarction. METHODS: In the MIMS2 study (Myocardial Infarction and Mental Stress 2), individuals who had been hospitalized for a myocardial infarction in the past 8 months were prospectively followed for 5 years. MACE was defined as a composite index of cardiovascular death and first/recurring events for nonfatal myocardial infarction and hospitalizations for heart failure. Reactive hyperemia index and flow-mediated dilation were used to measure microvascular and endothelial function, respectively, before and 30 minutes after a public-speaking mental stress task. Survival models for recurrent events were used to examine the association between vascular response to stress (difference between poststress and resting values) and MACE. Reactive hyperemia index and flow-mediated dilation were standardized in analyses. RESULTS: Of 263 patients (the mean age was 51 years; range, 25-61), 48% were women, and 65% were Black. During a median follow-up of 4.3 years, 64 patients had 141 adverse cardiovascular events (first and repeated). Worse microvascular response to stress (for each SD decrease in the reactive hyperemia index) was associated with 50% greater risk of MACE (hazard ratio, 1.50 [95% CI, 1.05-2.13]; P=0.03) among women only (sex interaction: P=0.03). Worse transient endothelial dysfunction in response to stress (for each SD decrease in flow-mediated dilation) was associated with a 35% greater risk of MACE (hazard ratio, 1.35 [95% CI, 1.07-1.71]; P=0.01), and the association was similar in women and men. CONCLUSIONS: Peripheral microvascular dysfunction with mental stress was associated with adverse events among women but not men. In contrast, endothelial dysfunction was similarly related to MACE among both men and women. These results suggest a female-specific mechanism linking psychological stress to adverse outcomes.