Background:
Mental stress-induced myocardial ischemia (MSIMI) is common in patients with ischemic heart disease (IHD) and has been associated with an elevated risk of mortality and adverse cardiac events. Microcirculation dysfunction may have a critical mechanistic role as MSIMI has been associated with microvascular constriction but not epicardial coronary stenotic burden. This may also play a role in the etiology of heart failure and other cardiovascular (CV) events. We explored the relationship of MSIMI to heart failure exacerbations and other categories of CV events using data from the REMIT trial.
Methods:
Patients with stable IHD (N=310) underwent mental and exercise tress testing; 44% had mental stress induced myocardial ischemia (by echocardiographic wall motion abnormality, left ventricular ejection fraction (LVEF) reduction of > 8%, and/or ischemic ST-change on ECG). Patients were followed for up to 6 years (median 4 yrs) for all-cause mortality and CV events resulting in hospitalization. Cox proportional hazard models, controlling for age, sex, and resting LVEF, were used to examine the associations of MSIMI indices with each CV category.
Results:
MSIMI, as a dichotomous variable, was not significantly associated with any CV category. Continuous mental stress-induced LVEF change scores were linearly associated with risk of being hospitalized for a heart failure exacerbation (HR = 2.35, 95%CI = 1.30 - 4.25,p=.005) (Table). This association did not significantly change after controlling for exercise-induced LVEF changes (HR = 2.35, 95%CI = 1.24 - 4.47,p=.009).
Conclusion:
In patients with stable IHD, every incremental 5% reduction in LVEF change induced by mental stress was associated with a 2.35 times greater risk of experiencing a hospitalization for heart failure exacerbation over an average 4-year period. This is independent of the risk conferred by traditional exercise testing.
Laboratory mental stress tests are weak inducers of myocardial ischemia