Background: Venous thromboembolic disease remains a difficult problem in the trauma patient population. The purpose of this study was to delineate the incidence and natural history of below-knee deep venous thrombosis (BKDVT) in high-risk trauma patients.
Methods: Patients were stratified into risk categories (low, high, or very high) for deep venous thrombosis on the basis of an institutional practice management guideline and known risk factors. All at-risk patients received either sequential compression devices (SCDs) or subcutaneous heparin (SQH) compounds, and high-risk patients also underwent weekly surveillance by duplex scanning. Very-high-risk patients had prophylactic inferior vena cava (IVC) filter placement. This prospective, observational study examines the duplex results on all high-risk patients. Data regarding method of prophylaxis, the incidence of proximal propagation on serial duplex examinations, and changes in management (anticoagulation or IVC filter placement) were collected on the high-risk patients who developed a BKDVT.
Results: Between March 1997 and June 2001, 601 patients were stratified into the high-risk category and underwent a total of 1,109 duplex examinations. Eighty-five patients (14.1%) had 113 BKDVTs. These patients underwent a total of 212 duplex examinations; all patients developed their BKDVTs within 34 days. Weekly incidence was 40 (47.1%), 25 (29.4%), 15 (17.6%), 1 (1.2%), and 4 (4.7%) for weeks 1 through 5, respectively. SCDs, SQH compounds, and SCDs with SQH compounds were used on 73, 3, and 9 patients, respectively. In 4 of 85 (4.7%) patients, the BKDVT propagated proximally to an above-knee location in 4 to 8 days. Two of these patients were anticoagulated, and two underwent placement of an IVC filter. One patient (1.2%) with a BKDVT that had not propagated on duplex study developed a pulmonary embolus.
Conclusion: Patients identified as high-risk by our practice management guideline had a 14.1% incidence of a BKDVT; 94.1% were diagnosed within the first 3 weeks of hospitalization. Proximal propagation occurred in 4.7% and led to changes in management. Serial duplex examination of the BKDVT alone, rather than systemic anticoagulation or IVC filter placement, appears to be a reasonable treatment alternative.