Detection of Asymptomatic Deep Vein Thrombosis by Real-Time B-Mode Ultrasonography in Hip Surgery Patients

Abstract

SummaryThe aim of this study was to prospectively evaluate the accuracy of real-time B-mode ultrasonography in the diagnosis of asymptomatic proximal deep vein thrombosis (DVT) in hip surgery patients. Venography was adopted as the gold standard. We studied 100 consecutive patients undergoing hip surgery: 60 patients for hip fracture and 40 patients for elective hip replacement. Bilateral real-time B-mode ultrasonography was performed prior to bilateral venography. The two diagnostic procedures were performed on the same day by different investigators unaware of the assigned prophylatic regimen for DVT Compressibility of the vein segment was adopted as the single criterion for DVT. Venography was performed and judged by radiologists unaware of the ultrasonography results. In 13 limbs venography was either impossible to perform or not adequate for judgement. Ultrasonography and an adequate venography was obtained in 187 limbs. A venography proven DVT was observed in 49 limbs (26.2%) and a proximal DVT in 21 limbs (11.2%). All the patients were asymptomatic for DVT. The sensitivity and specificity of real time B-mode ultrasonography for proximal DVT were 57% (95% confidence interval: C. I. 36–80) and 99% (C. I. 99–100), respectively and the positive and negative predictive values were 93% (C.I. 73–100) and 95% (C.I. 91–97), respectively. The sensitivity and specificity for overall DVT were 25% (C.I. 11–38) and 99% (C.I. 97–100), respectively and the positive and negative predictive values were 92% (C. I. 73–100) and 79% (C.I. 76–85), respectively. Our data indicate that realtime B-mode ultrasonography for its high specificity could make venography unnecessary in patients with positive results. However, because of its low sensitivity it cannot be used for the screening of DVT in asymptomatic patients, nor can it replace venography for outcome measurements in clinical trials on DVT prophylaxis.

Duplex Ultrasound for Thromboembolism

“…30 The sensitivity of detecting asymptomatic calf DVT is lower and ranges from 33% to 58%. 1,9,11,17 These findings reinforce the importance of experienced sonographers in making an accurate diagnosis.…”

Sonography for Deep Venous Thrombosis

“…Imaging usually begins at the brachial level and continues commonly bidirectional as a reflection of the cardiac cycle (Fig. 6,[55][56][57][58][59][60][61][62] When available, the results of the sonogram should be compared with MR venography, CT venography, or contrast venogram. Spectral waveform evaluation is especially important in the upper extremity evaluation, and, if a unilateral examination is ordered, the contralateral subclavian vein should also be studied.…”

The Diagnostic Approach to Acute Venous Thromboembolism

“…Without prophylaxis, the risk of DVT is approximately 50% after total hip replacement and as high as 65% after total knee replacement (89). Prospective clinical trials enrolling consecutive patients and using previously established objective criteria for CV and US with independent, blinded comparisons of the two techniques were assessed (level 1 trials) (43,68,(90)(91)(92)(93)(94)(95)(96)(97)(98). Other studies were deemed level 2 (76,(99)(100)(101)(102).…”

“…Because of the above-described technical considerations, however, the sensitivity is frequently much lower (67). The sensitivity of US for detecting isolated calf DVT in asymptomatic high-risk patients is even lower, ranging from 33 to 58% (91,93,97,107). Clinical investigations evaluating US techniques for calf DVT are both level 1 and level 2.…”