Coronary artery calcium, exercise tolerance, and CHD events in asymptomatic men

Abstract

Coronary artery calcium (CAC) scores ≥100 are predictive of CHD events in asymptomatic men. Exercise tolerance of ≥10 METs predicts lower event rates in CHD patients; however, its relationship with events in individuals with subclinical atherosclerosis is less known. Participants were 710 asymptomatic men from the Aerobics Center Longitudinal Study whose exercise tolerance (ET) was quantified (<10 or ≥10 METs) and whose CAC score was ≥100 as measured by electron beam tomography. During 3.5 years of follow-up 59 CHD events occurred. The age-adjusted hazard ratio (HR) of CHD events was 0.26 (95% CI = 0.15–0.45) in men whose ET was ≥10 METs compared with men whose ET was <10 METs. Adjustment for CHD risk factors and abnormal exercise ECG did not change the association between ET and CHD. The extent of underlying atherosclerosis did not influence the association between ET and CHD; for example, the HR for CHD events in the ≥10 MET group among men with CAC scores <400 and ≥400 was 0.16 (95% CI = 0.05–0.56) and 0.23 (95% CI = 0.11–0.46), respectively. In asymptomatic men with subclinical coronary atherosclerosis, an ET of ≥10 METs identifies patients at lower risk for manifest CHD.