Abstract 636: Influence of Gender on Platelet Reactivity in Patients With and Without Obstructive Coronary Artery Disease
Background: Recent results suggest that atherogenesis differs in women and men. Because platelet reactivity and microthrombosis contribute to atherogenesis, we characterized platelet function in men and women with and without obstructive coronary artery disease (CAD) demonstrated by coronary angiography.
Methods: Platelet function was analyzed with the use of flow cytometry in whole blood obtained from 45 patients at the time of cardiac catheterization. Platelet activation in response to ADP, thrombin and platelet activating factor (PAF) was assessed with the use of fluorochrome labeled fibrinogen and PAC-1 for activation of glycoprotein IIb-IIIa, anti-CD62 for surface expression of P-selectin, and annexin-V for exposure of phosphatidylserine that has been associated with platelet activation and procoagulant activity.
Results: Women (n=18) and men (n=27) did not differ with respect to age (60±11 and 61±12 years), presence of diabetes (33% and 26%), or pretreatment with clopidogrel (72% and 67%). Obstructive coronary artery disease (stenosis > 70%, thrombolysis with positive biomarkers, and/or past CABG) was diagnosed in 10 women (56%) and 17 men (63%). Women with obstructive CAD had two-fold higher ADP-induced platelet reactivity and thrombin-induced annexin binding than those without angiographic evidence of CAD (Table⇓). Differences were less pronounced in men (Table). Platelet activation in response to PAF was similar in those with and without CAD but greater in women than in men (p<0.02 for PAC-1 binding).
Conclusion: Greater platelet reactivity is evident in women with obstructive CAD than in those without and this may contribute to a greater risk of subsequent cardiac events.