Prolonged prophylaxis in postoperative medicine.

Major surgical procedures, especially orthopedic surgeries, such as elective hip or knee replacement, are associated with a high incidence of postoperative deep vein thrombosis (DVT) and potentially fatal pulmonary embolism (PE). Although most surgeons exercise thromboprophylaxis, the length of time of prophylactic measures is at this time uncertain. With increasing shortening of in-hospital stays and thus shorter times of prophylaxis, increasing numbers of "late" PE are being recognized. These observations have raised the issue of postdischarge continuation of prophylaxis. This problem was recently addressed by four studies involving hip arthroplasty patients. In all trials prophylaxis was performed with low-molecular-weight heparins (LMWH). Two studies used enoxaparin, two used dalteparin. Duration of in-hospital treatment lasted from 7 to 15 days. The length of postdischarge prophylaxis ranged from 21 to 28 days. DVT was diagnosed by bilateral venography. In all instances there was a significant reduction in DVT in the treated patient group, compared with those who were not treated after discharge. It is assumed that this reduction also impacts the frequency of potentially fatal PE. The trials suggest that thrombosis prophylaxis should be continued in patients following discharge from hospital after major surgical procedures, especially when risk factors persist.