Effects of Treadmill and Pacing Stress Testing on Peripheral Arterial Thromboxane, Platelet Function and Catecholamine Activities in Patients with Chronic Coronary Artery Disease

Abstract

Two different methods of causing myocardial oxygen demand and supply imbalance; symptom limited treadmill exercise and right atrial pacing stimulation, were used to examine the alteration of hemodynamics and the effects upon sympathetic nerve activities, platelet functions and prostaglandin synthesis in patients with coronary artery disease (CAD). Age and sex distributions, the cardiothoracic ratio, left ventricular endiastolic pressure, ejection fraction and coronary artery obstructions of the patients did not differ significantly between the two tests. Arterial blood samples were obtained to assay for plasma catecholamine, β-thromboglubulin (βTG), platelet factor 4 (PF4), TXB2 (thromboxane B2) and 6 ketoPGF1-α (6 ketoprostaglandin F1-; ) without any difficulties before and immediately after testing. The arterial systolic pressure and pressure rate product (PRP) were changed more significantly by treadmill exercise than pacing, while the DPTI/TTI (diastolic pressure time index/tention time index) ratio and ST segment deviations showed similar changes with both tests. The plasma NE (norepinephrine) level, βTG, PF4, and TXB2/6 ketoPGF1-α were significantly elevated by treadmill exercise, but not by pacing. 6 ketoPGF1-α was not markedly affected by either tests. There were no significant differences between the patients with and without anginal pain either in hemodynamics or metabolites. Significant relationships were observed between changes in plasma NE levels and the PRP (r=0.76, n=26, p < 0.01) and also changes in the arterial systolic pressure (r=0.64, n=26, p < 0.01), but there were no significant correlations between any other hemodynamic parameters with plasma NE, platelet function, prostaglandin activity, or between each metabolite. These results suggest that the hemodynamic effects might have a more significant influence on platelet function and arachidonic acid metabolism in patients with CAD than limited cardiac stimulation even if myocardial ischemia can be provoked. © 1987, The Japanese Society of Internal Medicine. All rights reserved.