The interaction of vasoactive substances during exercise modulates platelet aggregation in hypertension and coronary artery disease.
BACKGROUND
Acute vigorous exercise, associated with increased release of plasma catecholamines, transiently increases the risk of primary cardiac arrest. We tested the effect of acute submaximal exercise on vasoactive substances and their combined result on platelet function.


METHODS
Healthy volunteers, hypertensive patients and patients with coronary artery disease (CAD) performed a modified treadmill exercise test. We determined plasma catecholamines, thromboxane A2, prostacyclin, endothelin-1 and platelet aggregation induced by adenosine diphosphate (ADP) and collagen at rest and during exercise.


RESULTS
Our results during exercise showed a) platelet activation (increased thromboxane B2, TXB2), b) increased prostacyclin release from endothelium and c) decreased platelet aggregation in all groups, significantly more in healthy volunteers than in patients with CAD (with hypertensives lying in between these two groups).


CONCLUSIONS
Despite the pronounced activation of Sympathetic Nervous System (SNS) and increased TXB2 levels during acute exercise platelet aggregation decreases, possibly to counterbalance the prothrombotic state. Since this effect seems to be mediated by the normal endothelium (through prostacyclin and nitric oxide), in conditions characterized by endothelial dysfunction (hypertension, CAD) reduced platelet aggregation is attenuated, thus posing such patients in increased risk for thrombotic complications.
Petidis
Konstantinos
K
2nd Propedeutic Department of Internal Medicine, Hippokration Hospital, Aristotle University of Thessaloniki, Greece. petidisk@med.auth.gr
Douma
Stella
S
Doumas
Michael
M
Basagiannis
Ilias
I
Vogiatzis
Konstantinos
K
Zamboulis
Chrysanthos
C
D000328:Adult; D002395:Catecholamines / Q000097:blood; D003324:Coronary Artery Disease / Q000097:blood* / Q000503:physiopathology*; D019332:Endothelin-1 / Q000097:blood; D004730:Endothelium, Vascular / Q000378:metabolism*; D011464:Epoprostenol / Q000378:metabolism; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D006973:Hypertension / Q000097:blood* / Q000503:physiopathology*; D008297:Male; D015539:Platelet Activation; D010974:Platelet Aggregation; D013928:Thromboxane A2 / Q000097:blood
D002395:Catecholamines; D019332:Endothelin-1; D013928:Thromboxane A2; D011464:Epoprostenol