Abstract 20778: Inducible Myocardial Ischemia Predicts Future Acute Coronary Syndromes in Healthy Individuals with a Family History of Premature Coronary Artery Disease
Background: Exercise-induced ischemia on myocardial perfusion imaging is associated with an increased risk of coronary artery disease (CAD) events in individuals referred for symptoms and/or with known CAD. This study was designed to determine the extent to which inducible ischemia predicts acute coronary syndromes (ACS) in completely healthy asymptomatic siblings of persons with premature CAD <age 60 followed for up to 25 years.
Methods: Siblings (n=1297, age 24-59 years, 54% female) were screened for traditional risk factors and underwent exercise treadmill testing with nuclear perfusion imaging and were followed for the development of ACS (mean follow-up 11.6 ± 5.1 years). The severity of ischemia was assessed by semiquantitative methods using the standard 17-segment model and then categorized by percent myocardium hypoperfused as none (0%), minimal (1 to <5%), mild (5 to <10%), moderate (10 to <15%), or severe (≥15%)
Results: ACS occurred in 134 subjects (10.3%) and included sudden cardiac death (n=13), acute MI (n=62), and unstable angina with revascularization (n=59). Minimal, mild, and moderate/severe ischemia was associated with an ACS incidence of 19.7%, 25.4%, and 38.9%, respectively (p for trend <0.0001). Kaplan-Meier event-free survival analyses by myocardial ischemia severity categories showed that even minimal and mild myocardial ischemia were associated with greater ACS incidence detectable as early as 2 years after baseline. A Cox proportional hazard model, adjusted for risk factors, showed that each 5% increment in myocardial hypoperfusion resulted in a 77% increase in the hazard of incident ACS (p<0.001).
Conclusion: These findings suggest that the presence of a long latent pre-clinical ischemic phase of CAD is relatively common in apparently healthy siblings of persons with premature CAD. Aggressive preventive efforts may beneficial in persons with a sibling history of premature coronary disease.
- Coronary artery disease
- Ischemic heart disease
- Subclinical atherosclerosis
- Myocardial perfusion
- © 2010 by American Heart Association, Inc.