Prophylaxis of postoperative thromboembolism with low molecular weight heparins

Abstract

To evaluate the thromboprophylactic use of low molecular weight heparins (LMWHs), publications from 27 orthopaedic trials and 35 studies of patients undergoing general or gynaecological surgery were scrutinized and subjected to a partial meta-analysis. In orthopaedic surgery, LMWHs were superior to placebo or dextran and at least as efficient as unfractionated heparin in the prevention of deep vein thrombosis (DVT). Compared with unfractionated heparin, one of the LMWH preparations significantly reduced the total incidence of DVT. The rate of non-fatal pulmonary embolism was 0.49 per cent in patients receiving LMWH and 1.22 per cent in controls. Seven orthopaedic patients (0.15 per cent) died from pulmonary embolism, none of whom received LMWH. In general surgery, the LMWHs were at least as efficient as unfractionated heparin, with a trend towards a lower risk of pulmonary embolism with the former. Compared with unfractionated heparin, LMWHs did not reduce the postoperative mortality rate, nor did they cause haemorrhage. LMWHs provide safe and efficient prophylaxis by administration once daily.

Incidence and natural history of deep-vein thrombosis after total hip arthroplasty

“…23 Charnley abandoned the use of phenindione because the benefit from a reduction in the mortality rate due to pulmonary embolism was matched by an increased mortality from gastrointestinal haemorrhage. 24 Coventry et al 2 recommended postponing anticoagulation with warfarin until the fifth postoperative day, but this would have failed to prevent three of the four cases of fatal pulmonary embolism which were reported by Warwick et al 16 Meta-analysis shows that both low-dose, unfractionated and low-molecular-weight heparin substantially reduce the incidence of venographically demonstrated DVT after THR from about 45% to about 23% 25 and about 19%, 26 although with some haemorrhagic side-effects. This reduction in DVT has been extrapolated to imply a reduction in the incidence of fatal pulmonary embolism, but no study has been powerful enough to demonstrate this.…”

Low molecular weight heparin and radical prostatectomy: a prospective analysis of safety and side effects

“…Moreover, some studies have shown less risk of thrombocytopenia and bleeding complications with LMWH compared with unfractionated heparin. 3,4 We report the results of a prospective study designed to address the safety of LMWH used in patients undergoing radical retropubic prostatectomy.…”

Risks and Benefits of Prophylaxis Against Venous Thromboembolism in Orthopaedic Surgery

“…In elderly people undergoing surgery for fracture of the hip, the incidence of fatal PE is probably higher than in elective surgery, at around 4%. 10,23,24 This is within the high-risk category under the THRIFT classification. Data from the PEP study, produced after this review, suggest that even after fracture of the hip the incidence of fatal PE is much lower.…”