A Guide to Venous Thromboembolism Risk Factor Assessment

Venous thromboembolism (VTE) remains a widespread clinical problem associated with signi~cant morbidity and mortality. It is estimated that VTE results in 300,000 to 600,000 hospitalizations each year in the United States [1]. Of these patients, 50,000 to 100,000 will die of a pulmonary embolism, which is presently the leading cause of preventable death in hospitalized patients [1,2]. Untreated deep vein thrombosis (DVT) predisposes patients to episodes of recurrent VTE and the development of the postphlebitic syndrome (PTS), which can involve a constellation of symptoms ranging from leg edema, pain, aching and tiredness, to the development of skin discoloration, scarring, and even open ulceration [3–7]. VTE and its post-thrombotic sequelae have a staggering impact on healthcare expenses, costing the United States over one billion dollars annually [8,9]. Surgical patients in particular are at a high risk for DVT since the surgical procedure itself is very traumatic and often accompanied by bed rest that increases venous stasis. Without appropriate prophylaxis, DVT rates range from 45–70% and 15–30% in orthopedic and general surgery patients respectively [2]. For this reason, surgeons should be aware of current guidelines that detail how to appropriately protect their patients from the development of DVT. The rationale for VTE prophylaxis is based on the fact that two-thirds of DVT cases are asymptomatic, and PE is most often clinically silent [3]. In addition, the clinical diagnosis of a DVT or PE is insensitive and unreliable since few of their signs and symptoms are speci~c. Implementation of treatment must be done before the complete clinical picture has developed, since the ~rst manifestation of the disease may be a fatal PE. Unrecognized and untreated DVT may also lead to long-term morbidity related to the development of the post-thrombotic syndrome and future episodes of recurrent VTE. Consequently, prevention is the key to reducing death and morbidity from VTE, and the key to appropriate prophylaxis is risk factor analysis (RFA). Even though the importance of preventing the development of VTE has been emphasized by a number of consensus conference guidelines over the past 20 years, the speci~c recommendations in the guidelines have not been universally adopted into clinical practice [1,10–13]. Various surveys over the past few years have reported wide practice variations in the prevention of VTE, including an under-utilization of prophylaxis and a lack of awareness among physicians of VTE as a problem. In a recent 1998 survey of 1,145 Fellows of the American College of Surgeons, Caprini showed that only 47% and 31% of the responding surgeons were familiar with the 1986 NIH Consensus Conference and the American College of Chest Physicians guidelines respectively [14]. An alarming 90% of the surgeons were not familiar with the 1992 THRIFT Conference or the 1992 European Consensus Conference Guidelines [14]. Some investigators feel that the availability and reinforcement of written protocols, particularly in non-teaching hospitals where VTE prophylaxis is signi~cantly underutilized, may improve the utilization of VTE prophylaxis [15]. It has already been shown that continual medical education (CME) programs and protocol implementation can signi~cantly increase the frequency with which physicians prescribe appropriate methods of VTE prophylaxis [16]. The 1998 Chest Consensus Guidelines emphasized the need for continuing educational programs to increase the use of appropriate prophylactic measures and the importance of risk factor assessment in diagnosing and treating DVT [17]. RFA is essential in surgical patients because prophylaxis is encumbered with risks (e.g., bleeding com-