ACETYLSALICYLIC-ACID MAY PROTECT THE PATIENT BY INCREASING FIBRIN GELPOROSITY - IS WITHDRAWING OF TREATMENT HARMFUL TO THE PATIENT

The effect of acetylsalicylic acid In preventing cardiovascular compli cations is ascribed to acetylation of the enzyme cyclo-oxygenase there by inhibiting prostaglandin synthesis. Acetylsalicylic acid, however, also acetylates fibrinogen. In the present pilot study, we investigate d the permeability, i,e. porosity, of the fibrin gel in male patients with stable angina pectoris treated with this drug, before and at 1 an d 2 weeks after withdrawal. Ten patients were treated with 75 mg and e ight with 160 mg. The results were compared to those in seven untreate d healthy controls. Bleeding times were longer during treatment and we re reduced after withdrawal indicating patient compliance. Fibrin gels were more porous during treatment although there were large interindi vidual variations in porosity. One week after withdrawal, the porosity was reduced by 30-41%, i.e. the network became righter (75 mg group P =0.001; 160 mg group P=0.002). The tightness was more pronounced after withdrawal than in the untreated controls. In conclusion. the protect ive effect of acetylsalicylic acid may be ascribed to its effect not o nly on platelets but also on fibrinogen. The withdrawal of acetylsalic ylic and may cause a markedly reduced fibrin gel porosity that we assu me is disadvantageous in patients with cardiovascular disease.