Aspirin has been demonstrated to be an effective prophylactic agent
against postoperative venous thromboembolic disease, but the optimum dosage
is unknown. We compared the efficacy of daily doses of 3.6 grams of aspirin
(high dose) with that of 1.2 grams (low dose) in 182 patients. All patients
were more than forty years old and all underwent a total hip replacement.
This randomized, prospective, double-blind study was done using only
objective dta for diagnosis. Twenty-three (44 per cent) of fifty-two women
who were treated with the low dose had thrombi, compared with eighteen (34
per cent) of fifty-three women who were given the high dose. Thrombi
developed in thirteen (32 per cent) and in eighteen (49 per cent) of
thirty-seven men who were given the high dose. There were no statistically
significant differences among the four groups, nor was there a significant
difference among the subgroups that were determined according to prior
history of venous thromboembolic disease. Therefore, the higher dose of
aspirin was neither more nor less effective than the lower dose. Our data
continue to support the use of 1.2 grams in men.