FLOW CYTOMETRIC DETECTION OF PLATELET ACTIVATION IN PATIENTS UNDERGOING DIAGNOSTIC AND INTERVENTIONAL CORONARY ANGIOGRAPHY

In 30 patients we investigated the expression of activated GPIIb/IIIa- complex as an indicator of in vivo platelet activation before and afte r coronary angiography/angioplasty. Patients were divided into three g roups according to aspirin treatment: group I: patients having a diagn ostic coronary angiography without aspirin (n=6); group II: patients h aving a diagnostic coronary angiography with low dose aspirin therapy (n=11); group III: patients having a coronary angioplasty with low dos e aspirin therapy plus aspirin i.v. (n=13). Platelets were identified in a flow cytometer by their characteristic light scatter profile and binding of anti-GP Ib, and activated platelets by an antibody to the a ctivated GP IIb/IIIa. Cardiac catheterization lead to an increase of t he mean anti-GP IIb/IIIa-fluorescence of the platelets and of the perc entage of platelets with an anti-IIb/IIIa-FL exceeding a fixed thresho ld value (subpopulation). While aspirin substantially inhibited the in crease induced by diagnostic angiography, the increase in the angiopla sty group was the greatest of all groups despite aspirin.