BETTER INCREASE IN FIBRIN GEL POROSITY BY LOW-DOSE THAN INTERMEDIATE-DOSE ACETYLSALICYLIC-ACID

Aim To investigate the influence on plasma fibrin gel structure of low and intermediate doses of acetylsalicylic acid in healthy individuals . The influence of acetylsalicylic acid on thrombin formation, fibrino lytic capacity and plasminogen inhibitor-1 in plasma was also investig ated. Methods Nineteen subjects were treated with 75 mg and 11 with 32 0 mg acetylsalicylic acid daily; eight subjects received both doses. F ibrin gel structure was determined by a permeability technique yieldin g a porosity constant (K-s), and the thromboxane metabolite 11-dehydro -thromboxane B-2 (TxM) was determined by an ELISA. Results Acetylsalic ylic acid increased fibrin porosity by 65% at 75 mg (P<0.001, n=19), w hereas lower increases were found at 320 mg (+22%, P<0.05, n=11). One week after withdrawal K-s had essentially returned to baseline (ns). U rinary thromboxane metabolites were suppressed during treatment (-61%, P<0.001 at 75 mg, n=19; -46%, P<0.01 at 320 mg, n=11). The intra-indi vidual comparison showed similar results (K-s+92%, TxM - 62% at 75 mg; K-s+5%, TxM-52% at 320 mg). Fibrinolytic capacity, plasminogen inhibi tor-1 levels and thrombin generation tin platelet-poor citrated plasma ) were not influenced. Conclusion Low dose acetylsalicylic acid causes the greatest increase in fibrin gel porosity; this may well be of the rapeutic importance.