Exercise tolerance in asymptomatic elderly men with fluoroscopically detected coronary artery calcification

Study objective: The value of detecting coronary artery calcification (CAC) , by cardiac imaging, for the diagnosis of coronary artery disease (CAD) in asymptomatic middle-aged men has been demonstrated. However, the incidence of CAC increases with age. The functional significance of CAC remains unkn own in asymptomatic elderly men. The purpose of this study is to explore wh ether CAC in asymptomatic aging men signifies the presence of cardiovascula r dysfunction during exercise. Design: This study was designed to address whether elderly asymptomatic men , selected because the) have CAC, have reduced exercise tolerance due to fu nctionally significant CAD. Participants and setting: Thirty-eight asymptomatic male volunteers (ages 5 0 to 75 years, mean [+/- SD] 64 +/- 7 years) with a normal resting ECG and at least one coronary risk factor, in a population study. Nineteen subjects had CAC detected by digital subtraction fluoroscopy in at least two major coronary arteries, and 19 subjects had no identifiable CAC, Methods and results: Each subject underwent a symptom-limited incremental e xercise test with 12-lead ECG monitoring and respiratory gas analysis. Four indexes of exercise oxygen transport were evaluated: peak oxygen uptake (( V)over dot O-2), lactic acidosis threshold, peak (V)over dot /heart rate ra tio, and (V)over dot O-2 relative to a work rate increase. Eleven of 38 sub jects (28%) were found to have reduced oxygen transport, which was defined as an abnormal reduction in more than two of the above four indexes of oxyg en transport, Five of the 11 subjects with reduced oxygen transport had CAC , and 6 subjects did not (not significant). Only one subject with CAC had e xercise ST depression. Conclusion: Significant CAC in asymptomatic men over age 50 does not signif y exercise limitation due to CAD.