Session V - Polytrauma
Deep Vein Thrombosis in Polytrauma: Anatomic Location of Clots and the Role of Magnetic Resonance Venography
James P. Stannard, MD1; Aloke K. Singhania, MD2; Robert R. Ben-Lopez, MD1; Edward R. Anderson, MD1; Rory C. Farris, BS1; David A. Volgas, MD1; Gerald McGwin, Jr., PhD1; Jorge E. Alonso, MD1;
Purpose: We report on the incidence and location of deep vein thrombosis (DVT) that occurs after high-energy skeletal trauma, and compare the results of magnetic resonance venography (MRV) and ultrasound in detecting the clots.
Methods: A total of 312 patients were enrolled in two separate prospective randomized studies regarding prophylaxis against DVT after skeletal trauma. Ultrasound and MRV readings were obtained of patients prior to discharge from the hospital and read in a blinded fashion. Of the patients, 222 had a pelvic or acetabulum fracture as part of their injuries, whereas 90 sustained skeletal trauma that did not include either fracture.
Results: Thirty-six patients (11.5%) developed DVT despite either pharmacologic or mechanical prophylaxis or both. Nine (10%) of the 90 patients who sustained polytrauma without a pelvis or acetabulum fracture developed a DVT. All of these patients sustained at least one fracture on the same side as the DVT, and only one patient had a clot in the pelvic vasculature. That patient had a femoral neck and shaft fracture and developed a DVT that involved the external iliac vein. Of the 222 patients who sustained injuries that included a pelvic or acetabular fracture, 27 developed a DVT (12.2%). The source of the clot was the pelvic veins in 12 (45%) and the lower extremity veins in 15 (55%). Four patients developed a pulmonary embolus (1.3%), with three occurring after pelvic or acetabular fracture (1.4%) and one after nonpelvic polytrauma (1.1%). Of the 13 patients who had a DVT located in the pelvic veins, the ultrasound was negative in 10, for a 77% rate of false-negative tests, but MRV was not negative in any of these patients. Of the 23 patients who had a lower extremity DVT, ultrasound was negative in three, for a false negative rate of 13%; MRV was negative or inconclusive in 8 and not done in 3 because of medical instability or claustrophobia. The rate of false negative MRV in the lower extremities was 40% (8 of 20). The anatomic location of DVT was as follows: external iliac vein, 9; common iliac vein, 4; internal iliac vein, 1; common femoral vein, 21; femoral vein, 5; and popliteal vein, 4. Some patients had clots that involved more than one vein, and three patients with pulmonary emboli and negative lower extremity ultrasound were too unstable to undergo MRV, preventing the determination of which pelvic veins were involved.
Conclusion/Significance: Pulmonary embolism and DVT remain significant problems after high-energy skeletal trauma despite adequate prophylaxis. Deep vein thrombosis involving the pelvic veins is a major component of thromboembolic disease in patients after pelvic or acetabular fractures (45%), compared with only 11% of pelvic vein involvement in patients who sustain lower extremity trauma. Ultrasound is an inadequate study for the diagnosis of pelvic DVT, with a false negative rate of 77%. It is an excellent tool for the diagnosis of lower extremity DVT and was more accurate than MRV in the extremities. Ultrasound should not be used to evaluate patients for DVT after significant pelvic or acetabular fractures. Magnetic resonance venography is an excellent tool for diagnosis in these patients, but the added cost and difficulty of obtaining MRV are not justified for patients who have high-energy skeletal trauma that does not involve the pelvis or acetabulum.