Asymptomatic deep vein thrombosis in patients undergoing screening duplex ultrasonography

Because of concerns for propagating clots into pulmonary emboli by the placement of pneumatic compression boots (PCBs), the standard of care at our institution was to perform a duplex Doppler ultrasound with compression (DUSC) before applying PCBs. We sought to determine the rate of asymptomatic preexisting deep vein thrombosis (DVT) in hospitalized patients who underwent DUSC before PCB.

We evaluated consecutive patients who underwent lower extremity DUSC within 48 hours of admission. All patients were assessed for DVT risk factors using the American College of Chest Physicians' criteria (American College of Chest Physicians Conference on Antithrombotic/Thrombolytic Therapy: Evidence-Based Guidelines, 9th Edition). A t test, Wilcoxon rank sum test, and χ(2) or Fisher exact test were used to compare patients characteristics according to DVT status. Logistic regression was used to determine the importance of each risk factor on the risk of DVT.

DUSC was performed during 1136 hospitalizations; 1071 patients were included in the dataset. Of those, 19 patients (1.8%) had asymptomatic DVT and had at least 1 risk factor; 16 (84.2%) had more than 1 risk factor. The only risk factors that were statistically significant were ambulatory dysfunction and thromboembolic disease history.

Few patients have asymptomatic DVT upon admission; all of these patients have at least 1 predisposing risk factor. There appears to be no need for DUSC prior to initiation of PCBs. DUSC evaluation for DVT may be of value if there is a history of previous DVT, ambulatory dysfunction, or more than 3 risk factors, as the information may change therapeutic approaches.