The role of prostacyclin during exercise in patients with chronic angina pectoris

To determine changes in platelet activity, prostaglandin metabolism and catecholamine release along with changes in hemodynamics during exercise, we measured these parameters before and immediately after treadmill exercise. Measurements were made on peripheral arterial blood simultaneously with a direct aortic pressure recording in 30 patients with coronary artery disease (Group 1), in 20 patients without significant coronary disease (Group 2), and in 11 young healthy volunteers as controls. At the peak of the exercise regimen, the ST segment depression was found to be significantly lower in Group 1 than in Group 2, whereas the changes in the DPTI/TTI ratio in Group 2 and the controls decreased with the increase in the duration of exercise. The increased serum lactate level at the intermediate level of exercise (420 +/- 20 sec) was significantly lower in the controls than in the other 2 groups. Changes in beta thromboglobulin, platelet factor 4, and plasma norepinephrine were similarly increased in all 3 groups by exercise. At the termination of exercise, however, 6 keto-prostaglandin F1 alpha in Group 1 was insignificantly elevated, whereas it increased from 42.9 +/- 7 pg/ml to 55.7 +/- 7.1 (p less than 0.05) in Group 2 and from 38.2 +/- 5.7 pg/ml to 45.1 +/- 6.8 (p less than 0.01) in the controls. These results suggest that decreased prostacyclin production in the vessel wall might be an indicator of myocardial ischemia, and that the administration of prostacyclin may modulate the coronary vascular tone exaggerated by exercise.