Changes of platelet function during exercise in ischemic heart disease.

To investigate the role of platelet in ischemic heart disease, plasma levels of β-thromboglobulin (βTG) and thromboxane B2 (TXB2) were measured in 12 normal subjects and 18 patients with effort angina pectoris (EAP), 14 with vasospastic angina pectoris (VSA), 31 with old myocardial infarction (OMI). Levels of βTG and TXB2 were monitored before, during and after an ergometer exercise.1) Plasma βTG levels at rest were significantly elevated in the patients with EAP and with OMI, compared to that in normal subjects (p<0.05).2) During ergometer exercise, plasma, βTG levels were significantly (p<0.05) increased in the cases of EAP, especially in the cases having significant ST depression, and chest pain at maximal exercise.3) TXB2 levels changed during exercise neither in the normal nor in the patients with ischemic heart disease.4) At rest, platelet aggregation by collagen were decreased in the cases with EAP, VSA and with OMI.5) There were no significant changes in TXB2 production by arachidonate and thrombin, at rest and during exercise in 4 groups.These results indicate that platelets are activated in the patients with ischemic heart disease. Measurement of plasma, βTG level may be useful to detect the presense of myocardial ischemia.