EFFECT OF COLD PRESSOR TEST AND AWARENESS OF HYPERTENSION ON PLATELET-FUNCTION IN NORMOTENSIVE AND HYPERTENSIVE WOMEN

Plasma beta-thromboglobulin (beta-TG) concentration, reflecting platel et function in vivo, was compared in fertile women with untreated esse ntial hypertension and age-matched normotensives, in two separate stud ies. In the first study, hypertensives and normotensives were aware of their blood pressure status. Blood was sampled through arterial and v enous indwelling catheters, and no difference in beta-TG was found bet ween the groups. Arterial beta-TG was significantly lower than venous concentration (p less-than-or-equal-to 0.05). Cold pressor test increa sed arterial beta-TG significantly in both groups (p < 0.05). In the s econd study, both women and investigator were unaware of blood pressur e status, and beta-TG concentration, platelet count, and mean platelet volume obtained by venipunctures were similar in the hypertensive and normotensive group. Thus, platelet function in vivo seems to be norma l in fertile hypertensive women, in contrast to the platelet dysfuncti on previously reported in hypertensive men. In women, as in men, plate let release occurred during venous catheter blood sampling ana during cold pressor test. However, at variance from men, platelet function wa s not influenced by awareness of blood pressure status in the hyperten sive females.