Pulmonary embolism in medical patients: improved diagnosis and the role of low-molecular-weight heparin in prevention and treatment.

Pulmonary embolism is the major complication of deep-vein thrombosis (DVT) and has been shown in autopsy studies to account for 5-10% of hospital deaths. Approximately 75% of fatal pulmonary emboli (PE) occur in medical patients, a clinically heterogeneous group of patients. Ten percent of deaths due to PE occur within the first hour of the acute thrombotic event. Unfortunately, only 25% of all PE are diagnosed and receive appropriate treatment. The major focus for preventing this complication in medically ill hospitalized patients is to provide venous thromboembolism (VTE) prophylaxis. Unfractionated heparin (UFH) was the mainstay for preventing VTE in hospitalized medical patients. However, over the past few years, low-molecular-weight heparins (LMWHs) have been shown to be at least as effective and safer in preventing VTE in this population. Although highly effective in preventing VTE, there remains a small incidence of thrombotic events. Therefore, clinicians must be attentive to the symptoms and signs that would indicate a PE. If a PE is confirmed, then appropriate treatment based on the clinical status of the patient with either LMWH or body-weight dose-adjusted UFH is indicated.