The efficacy of three prophylactic regimens against deep venous
thrombosis was assessed in 135 patients who were more than thirty-nine
years old and had a total hip replacement. The three regimens were 1.2
grams of aspirin daily, 0.3 gram of aspirin daily, and external pneumatic
compression of the calf and thigh combined with low-molecular-weight
dextran that was given for three days, beginning during the operation. In
all patients, detection of fresh thrombi was by the fibrinogen-uptake test,
cuff-impedance plethysmography, and venography. New venous thromboses
developed in twenty-nine of forty-eight patients receiving 1.2 grams of
aspirin and in twenty-six of forty-three receiving 0.3 gram of aspirin,
indicating that the lower dose of aspirin had no advantage. Thromboembolic
disease developed in only nine of forty-four patients who were on the
regimen of external compression and dextran. This combination was
significantly better than aspirin in both men and women. Dextran appeared
to be associated with excessive bleeding when given in doses of more than
500 milliliters during the operation, but not when given in less than that
amount.