Intravenous acetylsalicylic acid, magnesium and their combination in experimental arterial thrombosis in rats

Intravenous acetylsalicylic acid (ASA) and magnesium (Mg) both possess anti platelet properties and are thus potential inhibitors of the formation of a rterial thrombi. Their effect on the dynamic aspects of arterial thrombus f ormation was investigated following intravenous administration of both subs tances alone and in combination. A blinded, placebo-controlled, in-vivo stu dy was performed in 71 rats. Thrombus formation was induced by a standardiz ed arteriotomy in the right femoral artery with inversion of the vessel wal l during subsequent closure. Thrombus formation was recorded on video tapes and analysed off-line for 30 min. Animals were randomly assigned to one of four groups: 20 mg bolus of ASA followed by 0.3 mmol/h Mg (ASA/Mg group); NaCl followed by 0.3 mmol/h Mg (Mg group); 20 mg bolus of ASA followed by N aCl (ASA group); or NaCl throughout the experiment (control group). In the ASA-treated groups, serum levels of thromboxane Bz were reduced significant ly, and the Mg-treated groups reached a serum level of Mg just above 2.0 mm ol/l. No significant differences were observed in initial or maximum thromb us area or in mean thrombus area during the study period. In the ASA/Mg gro up, a trend towards reduced thrombus formation was observed (P = 0.06). In the same group, seven of 22 animals developed an occlusive thrombus (P < 0. 01), an unexpected adverse event possibly related to the combined administr ation of ASA and Mg. Blood Coag Fibrinol 10:351-357 (C) 1999 Lippincott Wil liams & Wilkins.