The venous thrombotic risk in nonsurgical patients.

The risk of venous thromboembolism is not restricted to surgical situations: previous surgery is encountered in less than one-third of fatal pulmonary embolism cases, and less than 30% of patients hospitalised because of venous thromboembolic events are surgical patients. Some nonsurgical situations, e.g. ischaemic strokes and myocardial infarction (AMI), have been identified as having a risk for thromboembolism. More recently, critically ill patients in intensive care wards have been shown to be exposed to a significant risk of deep venous thrombosis. More often, at-risk situations in nonsurgical patients are less well defined. Clinical trials assessing the efficacy and safety of prophylactic methods in nonsurgical patients are rare, with the exception of those involving stroke and AMI. Several clinical trials have demonstrated that low molecular weight heparins are a suitable alternative to low dose unfractionated heparin in medical patients, offering a decrease in the number of injections and a lower potential for heparin-induced thrombocytopenia. Further research is needed to characterise the extent and duration of the risk of thromboembolism in nonsurgical patients, and the global benefit/risk ratio of various methods of prevention.