In this study, we investigated circulating beta-endorphin, ACTH and cortisol in subjects with suspected coronary artery disease (CAD) and in patients with CAD during stress testing. Group I: 18 subjects, all male (average age 48 +/- 9 yrs) with suspected (CAD) were enrolled. Group II: 35 patients, 30 males and 5 females (average age 54.3 +/- 7 yrs) with CAD, were enrolled. Ten patients had previous myocardial infarction. In all patients that underwent coronarography a stenosis > 75% was found in at least one coronary artery. The stress test was performed with a cycloergometer, increasing work loads 25 watt every 2 min. All subjects and patients were in the recumbent position for at least 30 minutes prior to testing. During this period a 3-way catheter was placed in the antecubital vein and blood was drawn for Beta-endorphin, ACTH and cortisol; additional blood samples were drawn using a pre-chilled syringe at maximum effort and during the recovery period.
Results: group I: 9 of the subjects with suspected CAD had either ECG or clinical signs of ischemic during the stress test. In subjects with a negative test, the test was carried out for a longer period of time and at a higher work load. There was an increase in Beta-endorphin and ACTH at peak exercise and during recovery. Plasma cortisol increase during the period of recovery. Group II: 16 of the 35 patients with CAD exhibited ECG signs of induced myocardial ischemia; there was no difference in work loads in patients with positive or negative stress test. Exercise time was reduced in all patients and plasma Beta-endorphin increased at peak exercise and recovery in patients with a negative stress test. In conclusion our study revealed a different response of Beta-endorphin, ACTH and cortisol plasma levels in subjects with suspected CAD and in patients with CAD during exercise testing.