SLR - May 2014 - Trevor E. Black

The Value of Lower Extremity Duplex Surveillance to Detect Deep Vein Thrombosis in Trauma Patients

Reference: Bandle, J., et al. The Value of Lower Extremity Duplex Surveillance to Detect Deep Vein Thrombosis in Trauma Patients. Journal of Trauma Acute Care Surgery, 74(2):  2013.

Scientific Literature Review

Reviewed By: Trevor E. Black, DPM
Residency Program: Grant Medical Center Podiatric Residency Program

Podiatric Relevance: Foot and ankle specific trauma comprises a large portion of the total trauma that is treated in emergency departments throughout the country. One of the most common complications that afflict trauma patients in general is venous thromboembolism (VTE), and while these patients are routinely administered prophylaxis, the incidence of VTE has been reported as high as 28 percent in acute trauma patients. Some trauma facilities have adopted venous duplex surveillance (VDS) to diagnose VTE even in the asymptomatic patient. Previous studies looking at the cost analysis of this practice have failed to evaluate the clinical utility. The clear understanding of the clinical and diagnostic utility as it compares to the cost of the procedure could greatly affect the standard of care as it relates to foot and ankle trauma patients. The aim of this study was to calculate the value of VDS stratified by risk for VTE with the goal of identifying those that would most benefit from routine surveillance.

Methods: A retrospective review was performed on all trauma patients admitted to Scripps Mercy Hospital between June 2006-December 2010. Medical records of all patients that were over 18 years of age, were bedridden for at least 72 hours, and had at least one venous duplex of the lower extremity during the admission were included in the study. Excluded patients included those who were ambulatory or those who were low risk for VTE. The data that was collected included age, sex, injury severity score, and the probability of survival. Patients were assigned to moderate, high, and highest risk. Patients received mechanical/chemical prophylaxis based on established guidelines which consisted of sequential compression devices and lovenox or heparin. VDS exams were performed every Tuesday for ward patients and every Monday/Thursday for ICU patients. The average yield of clinically relevant results was compared to the cost of providing the VDS study.

Results: Eleven thousand two hundred fifty-eight patients were admitted to the trauma service during the data collection period. Nine thousand eighty-nine patients were ambulatory or low risk. Two thousand one hundred and sixty-nine patients received at least one venous duplex during admission. The risk stratification of patients yielded the following results: 220 moderate risk; 1,173 high risk; 776 highest risk. Four thousand three hundred fifty-seven VDS exams were performed. There was an average of two exams per patient. A new DVT was identified in 196 patients (9 percent). Forty-three patients had bilateral DVT. One hundred thirty-two patients (17 percent) in the highest risk group were found to have DVT. By comparison, 62 patients (5 percent) in the high risk and two patients (<1 percent) in the low risk had DVT. Mean time to diagnosis was as follows: 1.5 days in moderate risk; 3.9 days in high risk; 7.6 days in highest risk. The rate of VTE diagnosed on VDS increased dramatically with increasing risk. Average time required by vascular technologist to find a DVT decreased dramatically as risk for VTE increased. 

Conclusions: Regular venous duplex for trauma patients identified VTE in all three risk stratified groups. The study focused on the cost benefit of utilizing regular VTE screening on patients and found that the cost in terms of time spent identifying a VTE decreased inversely proportional to an increase in the risk for developing the VTE. In the highest risk group, new DVT was identified in 1/9 patients. The development of VTE in the setting of hospitalization subjects the institution to significant punitive reductions in reimbursement for the services provided. The implementation of scheduled VTE screening is not widespread, but the current study suggests strong benefit from the standpoint of patient care and from a cost-benefit analysis. 

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