Summary
We performed a retrospective analysis on the influence of three types of anaesthesia
on the incidence of deep vein thrombosis (DVT) following total hip replacement (THR)
in consecutive patients randomized to either the low molecular weight heparinoid Otg
10172 (97 patients), of placebo (99 patients). Ninety patients were operated under
epidural anaesthesia, 77 patients under psoas compartment block with additional inhalation
anaesthesia, and 29 patients under general anaesthesia. DVT assessment was performed
by bilateral venography between days 8 and 12 postoperatively. The overall incidence
of DVT in the 196 patients was 37% in the epidural anaesthasia group, 35% in the psoas
compartment block group, and 36% in the general anaesthesia group. Although the incidence
of DVT in patients randomuedto placebo was similar in the two anaesthesia groups (53%),
there was an important reduction of the occurrence of proximal DVT by the heparinoid
in the psoas compartment block group (from 20 to 0%), compared to the epidural anaesthesia
group (from 27 to l8%) (p <0.0061). Significant y more minor wound hematomas occurred
in the psoas compartment block group as compared to the epidural anaesthesia group
(p <0.05). Synergrsm of thrombin generation inhibition by the heparinoid and inhibition
of plateletlggregation at the damaged vessel wall, by high local concentrations of
bupivacaine in the psoas compartment block technique, is proposed as a possible mechanism
behind this observation.
