Current research supports the use of blood-thinners to help acutely ill, hospitalized patients minimize the risk of death from a pulmonary embolism (PE) and its precursor deep vein thrombosis (DVT).

To provide clinical evidence of how to most effectively minimize risk of DVT, a researcher from Brigham and Women's Hospital (BWH), in an international clinical trial, found that critically ill patients at risk for DVT and PE who received a once daily low molecular weight heparin - dalteparin - versus placebo, experienced a 45 per cent reduction in risk of a DVT.

According to the study's senior investigator, BWH's Samuel Z Goldhaber, a cardiologist who specializes in DVT and PE, "Patients who fit the profile - including those with cancer, respiratory and congestive heart failure - should be considered at-risk for DVT or a PE and be closely monitored. Previous research has demonstrated that undetected DVT can lead to pulmonary embolism, a potentially fatal condition in patients who are otherwise recovering well from other medical illnesses. For example, in patients with cancer, many die not from the condition itself but from a pulmonary embolism. At-risk patients and their families need to take proactive measures, and ask their physicians if the hospital treatment plan includes measures to prevent DVT."

Researchers analyzed 3,076 hospitalized patients who were randomized to receive either dalteparin 5,000 units per day or a placebo for 14 days. Patients were followed for 90 days. Researchers found that patients taking dalteparin experienced a 45 per cent reduction in the development of DVT. There was no significant increase in major bleeding among patients receiving the blood thinner, dalteparin, compared with the placebo group.

"These results provide physicians with concrete evidence that DVT and PE can be effectively treated in at-risk populations. The benefits far exceed the risks in this population," Goldhaber said adding, "This study's results are a call-to-action to ensure all hospitalized patients with medical illness receive a proven DVT prevention plan."

DVT, a medical condition that occurs when a blood clot forms in one of the body's large veins, put groups including elderly hospitalized patients and those who have had recent surgery, cancer, or previous blood clots at risk of death. According to the American Heart Association, DVT occurs in approximately two million people a year. More than 600,000 of those with DVT are at risk of a blood clot "breaking off," migrating to the lungs and blocking the pulmonary artery.

The PREVENT Trial was sponsored by Pfizer, the manufacturer of dalteparin.

Results of this clinical trial, known as "PREVENT" (Prospective Evaluation of Dalteparin Efficacy for Prevention of VTE in Immobilized Patients Trial), was published online in the August 2, 2004 issue of Circulation and in print on August 17, 2004.