Longer post-op VTE prophylaxis needed

The risk of venous thromboembolism (VTE) after many different types of surgery is greater and lasts for longer than previously thought, new research finds. The large study showed that the risk of VTE peaks at 3 weeks following surgery but risks are substantially increased up to 12 weeks post-operatively. It also found that risks for VTE were greatest after joint replacement surgery and surgery for cancer. In an accompanying editorial, vascular surgeon Dr Alexander Cohen (King's College Hospital, London, UK) says the study "confirms and broadens the findings of existing studies on the ongoing risk of VTE after surgery" and "is a wake-up call to all surgeons." Using data from the prospective Million Women Study in the UK, the researchers, which included the George Institute for International Health in Sydney, examined questionnaires linked with National Health Service hospital admission and death records for almost 948,000 middle-aged women. During an average follow-up of 6 years there were almost 240,000 hospital admissions for surgery and 5,000 admissions for VTE, and a further 270 women died from VTE. Compared with not having surgery, women were almost 70 times more likely (relative risk 69.1) to be admitted with VTE during the first six weeks after an inpatient operation - with the peak incidence being three weeks following surgery - and almost 10 times more likely after a day case operation (RR 9.6). The risks were lower but still elevated seven to 12 weeks after surgery, with women almost 20 times more likely to have a VTE compared with those undergoing no surgery (RR 19.6). Risk also varied considerably by type of surgery, being highest after inpatient surgery for hip or knee replacement (relative risk 220.6) and cancer (RR 91.6) within the first six weeks postoperatively. In his editorial, Dr Cohen said the findings were clinically important as most patients receive preventive treatment only while in hospital and median stays for surgical patients worldwide are six days, so in most cases, thromboprophylaxis stops two weeks before the peak incidence of VTE. One reason for the poor uptake of prolonged prophylaxis is the relative inconvenience of parenteral anticoagulants. “Newly available oral anticoagulants will be important if prolonged treatment is needed," he concluded. BMJ 2009; published online before print.    ...