title: Enhanced platelet aggregability under high shear stress after treadmill exercise in patients with effort angina.
abstract: Platelet activation induced by shear forces occurring in a stenosed coronary artery is one of the mechanisms of coronary thrombosis. We evaluated the shear-induced platelet aggregation (SIPA) dynamics in patients with effort angina during treadmill exercise. SIPA was measured by a rotational cone-plate aggregometer. SIPA was markedly increased by exercise from 71.2 +/- 8.9% to 81.9 +/- 7.6% (p < 0.01) in the patient group. Although epinephrine concentrations were elevated, its rate of increase was not correlated with that of SIPA. Yohimbine partially inhibited the exercise-induced increase in SIPA. In contrast, a significant correlation between the changing rate of plasma von Willebrand factor (vWF) larger multimers and that of SIPA (r = 0.74, p < 0.05) was observed. Exercise-augmented SIPA is probably dependent on an increase in vWF larger multimers rather than platelet alpha2-receptor activation. Prevention of the interaction between vWF and its platelet receptors may play some role in decreasing the risk of coronary thrombosis during exercise.
authors.affiliation: Department of Medicine and Gerontology, Kyorin University, Tokyo, Japan.
authors.forename: J
authors.initials: J
authors.lastname: Tokuue
authors.forename: J
authors.initials: J
authors.lastname: Hayashi
authors.forename: Y
authors.initials: Y
authors.lastname: Hata
authors.forename: K
authors.initials: K
authors.lastname: Nakahara
authors.forename: Y
authors.initials: Y
authors.lastname: Ikeda
mesh_terms: D000328:Adult; D000368:Aged; D000787:Angina Pectoris / Q000097:blood*; D004837:Epinephrine / Q000097:blood*; D015444:Exercise; D005080:Exercise Test; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010974:Platelet Aggregation; D013314:Stress, Mechanical
chemical_list: D004837:Epinephrine