Venous thromboembolism prophylaxis in the medical patient: controversies and perspectives.

Despite the high morbidity and mortality associated with venous thromboembolism in hospitalized at-risk medical patients, the publication of large-scale studies showing that prophylaxis is effective in this patient group, and the presence of international guidelines, prophylaxis rates in medically ill patients remain suboptimal. Studies show that low-molecular-weight heparins, given once daily, are at least as effective as unfractionated heparin usually given thrice daily with equivalent or improved safety profiles, and that thrice-daily dosing of unfractionated heparin might be more effective than twice-daily dosing. However, the most recent American College of Chest Physicians guidelines do not distinguish between these regimens, and twice-daily unfractionated heparin is still commonly used in the United States. Furthermore, the optimal duration for out-of-hospital and extended prophylaxis for specific patient groups is not established. Finally, there are few data on the use of mechanical methods in this patient group and no established standard of care for prophylaxis of special patient populations, such as obese patients or those with renal insufficiency. Even though prophylaxis entails additional acquisition costs, it can reduce the incidence of venous thromboembolism, which can improve care and decrease overall costs.