Background: Current guidelines for assessing the risk of experiencing a hospitalized CV event discourage stress testing of asymptomatic individuals; however, these recommendations are based on evidence gathered primarily from those aged <60 years, and do not address the possibility of unrecognized “silent myocardial ischemia.”
Methods: We performed dobutamine cardiac magnetic resonance stress testing funded by the United States National Institutes of Health in 466 consecutively recruited participants aged >55 years without CV-related symptoms, but otherwise at increased risk for a future CV event due to pre-existing coronary artery disease (CAD), hypertension or diabetes mellitus. After testing, personnel blinded to the stress test results contacted participants at 4-month intervals for the next 5 years to determine and verify the incidence of post-stress testing hospitalized CV events. After accounting for the Framingham risk score, log-rank test and Cox proportional hazards models were used to determine the additional predictive value of the stress test results for forecasting hospitalized CV events.
Results: Participants averaged 69±8 years in age; 49% were men, 79% were Caucasian. Thirty-eight hospitalized CV events occurred during the mean follow-up of 58 months. After accounting for an individual’s Framingham risk score, stress-induced left ventricular (LV) wall motion abnormalities (WMA) indicative of ischemia were associated with future hospitalized CV events in men 3.61 (95% CI: 1.53-8.03; p=0.005), but not in women (p=0.55). This relationship was driven by the strong association between inducible LV WMA and hospitalized CV events in those asymptomatic men with pre-existing risk factors for but not with known CAD nor having sustained a prior CV event.
Conclusions: In asymptomatic middle aged and elderly men at increased risk for but yet to experience a CV event, an independent association exists between stress testing results and future hospitalized CV events. This finding raises the possibility to re-consider stress testing high risk elderly men to uncover silent ischemia and identify those at risk of a future hospitalization for a CV event.