Of the patients who had adequate venograms,
DVT was found in 21.2% of those who received enoxaparin and in 23.5%
of those who received tinzaparin. Rates of proximal and distal DVT were
similar in the two groups. There were no differences in bleeding rates
or transfusion requirements.
These three prevention trials indicate
that for prevention of DVT after hip or knee replacement, tinzaparin
is superior to placebo and roughly equivalent to warfarin and enoxaparin.
Note that even after aggressive prophylaxis, the rate of DVT is approximately
20% in these patients. Most of this DVT is distal in location and without
symptoms. It appears that if prophylaxis with warfarin of LMWH is given
for at least 7-10 days, the rate of fatal pulmonary embolism is very
low.
