Vascular reactivity to mental stress is associated with poor cardiovascular disease outcomes in females following acute coronary syndrome

Background: We aimed to test the hypothesis that peripheral endothelial dysfunction induced by mental stress may predict cardiovascular events after acute coronary syndrome beyond traditional cardiovascular disease risk factors. Methods: This was a prospective study in which 417 patients who had acute coronary syndrome were enrolled in two sites at the US and Qatar. Cardiovascular disease risk factors such as past medical history, blood pressure, heart rate, peripheral endothelial dysfunction, and response to three different mental stress examinations (Stroop Color Word, Arithmetic, and Spiral Omnibus) as assessed by ratio of reactive hyperemia tonometry (EndoPAT) with stress over EndoPAT at rest were obtained at baseline. Major adverse cardiac events were then recorded at 1 year after the index event. Results: There were no differences in baseline peripheral endothelial dysfunction or vascular response to mental stress between the US vs. Qatar patients. Women were more likely to experience major adverse cardiac events in the year following acute coronary syndrome (relative risk 2.42, 95% confidence interval 1.53-3.84, P = 0.044), and had a significantly lower mental stress ratio compared to women who did not (1.0 ± 0.17 vs. 1.20 ± 0.17, P = 0.04). In multivariate analyses stratified by sex, baseline peripheral endothelial dysfunction (EndoPAT < 1.7) (χ² = 8.0, P = 0.005) and mental stress ratio (χ² = 7.7, P = 0.006), were independently predictive of major adverse cardiac events in women, but not men. Conclusion: The current study demonstrates that in women both baseline endothelial function and vascular function in response to mental stress ratio are predictive of worse cardiovascular disease outcomes 1 year after acute coronary syndrome. The study may suggest an important mechanism for adverse clinical outcomes in women following acute coronary syndrome.