A COMPARISON OF COMPRESSION ULTRASOUND WITH COLOR DOPPLER ULTRASOUND FOR THE DIAGNOSIS OF SYMPTOMLESS POSTOPERATIVE DEEP-VEIN THROMBOSIS

Background: Despite advances in primary prophylaxis, venous thromboemb olism still occurs ina considerable number of high-risk surgical patie nts. Screening with conventional ultrasound imaging to detect asymptom atic deep vein thrombosis (DVT) has been suggested as a strategy to im prove management of such patients, but it is insufficiently sensitive. We evaluated the ability of color Doppler ultrasound to improve the s ensitivity of compression ultrasound in the detection of asymptomatic DVT in high-risk orthopedic patients. Methods: We prospectively evalua ted bilateral compression and color Doppler ultrasound measurements of the entire leg in 204 consecutive patients who underwent elective hip or knee replacement surgery, using contrast venography as the referen ce test. The sensitivity, specificity, and positive predictive value o f the ultrasonography tests were determined. Results: The sensitivity, specificity, and positive predictive value (with 95% confidence inter vals [CIs]) of compression ultrasound for the detection of proximal DV T were 60% (39%-81%), 96% (92%-99%), and 71% (48%-89%), respectively. The sensitivity, specificity, and positive predictive value (with 95% Cls) of compression ultrasound for the detection of calf vein thrombos is were 33% (18%-52%), 91% (83%-96%), and 58% (34%-80%), respectively. Color Doppler ultrasonography did not identify any additional proxima l or calf vein thrombi to those detected by compression ultrasound alo ne. The sensitivity for all thrombi was 47% (95% CI, 34%-61%) with a p ositive predictive value of 65% (95% CI, 48%-79%). Conclusions: Color Doppler ultrasonography has a moderate to low accuracy for the detecti on of DVT in patients who have bad hip and knee replacement surgery. C olor Doppler ultrasonography does not increase the detection rate for asymptomatic DVT over compression ultrasound and thus cannot be recomm ended as a screening test in this setting.