Exercise Thallium Tomography Predicts Future Clinically Manifest Coronary Heart Disease in a High-Risk Asymptomatic Population

BACKGROUND: Exercise testing, even when combined with radionuclide perfusion imaging, does not accurately predict future clinical coronary heart disease (CHD) in low-risk asymptomatic populations. We hypothesized that these tests would perform better in a higher-risk population with a high prevalence of occult CHD. Siblings of persons with premature CHD represent such a group in whom it would be advantageous to identify affected individuals before the occurrence of clinically manifest CHD. METHODS AND RESULTS: Exercise thallium scintigraphy was performed in 264 asymptomatic individuals less than 60 years of age who had a sibling with documented CHD before age 60. Despite an average age of only 46 years at the time of screening, 19 of 264 siblings developed clinical CHD (sudden death in 1, myocardial infarction in 10, coronary revascularization in 8) over a mean of 6.2 years (range, 1 to 9 years) of follow-up. Abnormal thallium scans were observed in 29% of men and 9% of women, while abnormal exercise ECGs occurred in 12% and 5% respectively. Of men >/= 45 years of age, 45% had an abnormal exercise ECG, thallium scan, or both. In contrast, only 3% of women 45 years of age at the time of screening and had a strikingly high incidence of CHD (6 of 12, 50%). CONCLUSIONS: Exercise thallium scintigraphy appears to be useful in the risk assessment of asymptomatic siblings of patients with premature CHD, particularly in male siblings who are 45 years of age or older.