Maehara K, Porszasz J, Riley M, Kang X, Detrano R C, Wasserman K
Department of Medicine, Harbor-UCLA Medical Center, Torrance, CA 90509-2910, USA.
Chest. 1998 Dec;114(6):1562-9. doi: 10.1378/chest.114.6.1562.
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 unknown in asymptomatic elderly men. The purpose of this study is to explore whether CAC in asymptomatic aging men signifies the presence of cardiovascular dysfunction during exercise.
This study was designed to address whether elderly asymptomatic men, selected because they have CAC, have reduced exercise tolerance due to functionally significant CAD.
Thirty-eight asymptomatic male volunteers (ages 50 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.
Each subject underwent a symptom-limited incremental exercise test with 12-lead ECG monitoring and respiratory gas analysis. Four indexes of exercise oxygen transport were evaluated: peak oxygen uptake (VO2), lactic acidosis threshold, peak VO2/heart rate ratio, and VO2 relative to a work rate increase. Eleven of 38 subjects (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 oxygen 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 exercise ST depression.
Significant CAC in asymptomatic men over age 50 does not signify exercise limitation due to CAD.
通过心脏成像检测冠状动脉钙化（CAC）对无症状中年男性冠心病（CAD）诊断的价值已得到证实。然而，CAC的发生率随年龄增长而增加。在无症状老年男性中，CAC的功能意义仍不明确。本研究的目的是探讨无症状老年男性中的CAC是否表明运动期间存在心血管功能障碍。
本研究旨在探讨因患有CAC而入选的老年无症状男性是否因功能性显著的CAD而运动耐量降低。
在一项人群研究中，38名无症状男性志愿者（年龄50至75岁，平均[±标准差]64±7岁），静息心电图正常且至少有一项冠心病危险因素。19名受试者通过数字减影荧光透视法在至少两条主要冠状动脉中检测到CAC，19名受试者未检测到可识别的CAC。
每位受试者均接受了症状限制递增运动试验，并进行12导联心电图监测和呼吸气体分析。评估了四个运动氧转运指标：峰值摄氧量（VO2）、乳酸酸中毒阈值、峰值VO2/心率比以及相对于工作率增加的VO2。38名受试者中有11名（28%）被发现氧转运降低，氧转运降低定义为上述四个氧转运指标中的两个以上出现异常降低。11名氧转运降低的受试者中有5名患有CAC，6名没有（无显著性差异）。只有一名患有CAC的受试者出现运动性ST段压低。
50岁以上无症状男性中显著的CAC并不意味着因CAD导致运动受限。
