PREVENTION OF DEEP VENOUS THROMBOSIS: CONCLUSIONS OF A CONSENSUS DEVELOPMENT CONFERENCE
Authors: Roberts H R 
Published: August 2018

Deep venous thrombosis (DVT) and pulmonary embolism (PE) are major health problems that lead to significant morbidity and mortality. In the United States, it is estimated that these two problems result in over 300,000 hospitalizations annually and available data indicate that 50,000 to 100,000 patients per year die of pulmonary embolism.

The advent of several diagnostic tests has permitted the identification of groups of patients at high risk for development of deep venous thrombosis and subsequent pulmonary embolism. Identification of these patient groups has led to therapeutic measures designed to prevent both deep venous thrombosis and subsequent embolic episodes. However, the efficacy of these preventive measures have not been widely adopted and reservations have been expressed regarding use of low dose anticoagulant drugs for prevention of DVT and PE, especially in surgical patients. Because of the apparent reluctance to adopt putative preventive measures for DVT and PE, the National Heart, Lung and Blood Institute convened a Consensus Development Conference on the issue of prevention in 1986. Experts from North America, Europe, and South Africa presented data, both pro and con, on prevention of DVT and PE, using one or more therapeutic regimens. An impartial Panel was then asked to arrive at a consensus statement on the following questions: 1) the level of risk of DVT and PE in different patient groups; 2) the efficacy and safety of prophylactic measures in these groups; 3) the recommended prophylactic regimens for different patient groups, and 4) remaining questions related to prevention of DVT and PE. Recommendations for prevention were based on the assumption that reduction in DVT would also result in reduction of pulmonary embolism. Furthermore, the consensus was based, at least in part, upon data combined from multiple clinical trials. Thus, combined data on 12,000 individuals in randomized clinical trials indicated that in appropriate patient groups, treated with low dose heparin, there was a 68 percent reduction in DVT, as measured by the 125I-fibrinogen uptake test and venography, and that there was a reduction of 49% in pulmonary embolism and a significant decrease in overall mortality resulting from pulmonary embolism.

Prophylactic measures for the following different patient groups were assessed: 1) general surgery; 2) orthopedic surgery; 3) urology; 4) gynecology-obstetrics; 4) neurosurgery and neurology; 5) trauma; and 6) medical conditions.

Basically, the following prophylactic regimens were considered: 1) low dose heparin; 2) low dose dihydroergotamine heparin; 3) dextran; 4) low dose warfarin; and 5) external pneumatic compression. In general terms, low dose heparin appears to be one of the more effective prophylactic regimens in certain groups of high risk patients. This regimen is not useful in orthopedic or certain neurosurgical procedures where heparin has been shown to be of little value or hazardous. In these cases, dextran, warfarin, or external pnuematic compression may be more beneficial. In some groups of high risk patients, combination of mechanical measures with anticoagulant agents appear to be of value in prevention of DVT and PE.

The recommendations of the Consensus Panel for Prevention of DVT and PE for each patient group will be assessed.