Selecting an agent for prophylaxis of venous thromboembolism

Q: It has become very common to use expensive low-molecular-weight heparins (LMWHs) for prophylaxis of deep venous thrombosis (DVT) in hospitalized medical and surgical patients. How can optimal prophylaxis be maintained while controlling the pharmacy expenses that result from the use of effective but costly antithrombotic agents? A: Over the past decade, the use of LMWHs has expanded exponentially as data and experience with the drugs have accumulated. As a result, hospital expenditures have increased dramatically, prompting many hospitals to evaluate LMWHs for potential formulary restriction or therapeutic interchange. The prevention of thrombotic complications is essential in the hospital setting, as venous thromboembolism (VTE), including DVT and pulmonary embolism (PE), is a major cause of morbidity and mortality in hospitalized patients, with 5–10% of all inpatient deaths associated with PE.1,–3 The frequency of VTE is 150-fold higher in hospitalized patients than in nonhospitalized individuals.4 An estimated 75% of all fatal PEs occur in medical patients, who account for 60% of all hospital admissions. 1 Early mortality rates of 3.8% and 38.9% in patients experiencing DVT and PE, respectively, have been reported.2 Patients undergoing major orthopedic surgery have an increased risk of fatal PE. Approximately 50–60% of patients undergoing total hip or knee replacement or surgery for hip fracture without prophylaxis will develop DVT, and up to 13% will die from PE.5,6 At the most basic level, the mean length of hospital stay increases from 5.4 days in patients who do not develop a DVT or PE to 11.5 and 12.4 days, respectively, in those who develop these complications (p < 0.0001 for both comparisons).6