Noninvasive Diagnosis of Deep Vein Thrombosis in Postoperative Patients

Abstract

The accuracy of noninvasive testing for the diagnosis of deep vein thrombosis (DVT) generally is less in asymptomatic patients than it is in those with symptoms suggestive of thrombosis. This is because asymptomatic DVT often is confined to the distal veins and, when it involves the proximal veins, the thrombi usually are smaller than in symptomatic patients with proximal thrombosis. Because the positive predictive value of noninvasive tests for asymptomatic DVT generally is 80% or less, abnormal results should be confirmed by venography. There are two main reasons why asymptomatic DVT is sought in the postoperative period: (1) to identify the need for full-dose anticoagulant therapy to prevent symptomatic episodes of venous thromboembolism (VTE), including fatal pulmonary embolism (this represents a form of secondary prophylaxis), and (2) to use this outcome as a surrogate for episodes of clinically important VTE in studies that are designed to evaluate methods of venous thrombosis prophylaxis. In relation to the first of these indications, evidence suggests that routine surveillance of high-risk patients to detect asymptomatic postoperative DVT does not result in improved clinical outcomes in patients who received appropriate VTE prophylaxis. In relation to the second indication, there is concern that asymptomatic VTE may not be a reliable surrogate for clinically important VTE, particularly if the effectiveness of different antithrombotic agents is being compared. Coupled with the comparatively low accuracy of noninvasive testing for asymptomatic DVT, this suggests that the results of such testing are unsuitable for the evaluation of new methods of prophylaxis in clinical trials.

Diagnosis and treatment of deep-vein thrombosis and approach to venous thromboembolism in obstetrics and gynecology

“…In many centres, ultrasound testing is limited to proximal veins (from the common femoral vein caudally to the region of the calf veins where they join the popliteal vein), for which the sensitivity is 97% for DVT. For DVT in the calf veins, sensitivity is only 73% (11).…”

Optimal management of venous thromboembolism in adolescent and young adult oncology patients

“…42 Incorporation of these tools into a diagnostic algorithm suggests that either D-dimer testing or diagnostic imaging further improves sensitivity and specificity. 43 For DVT, the accepted modality is now the compression ultrasound (validated against venogram, the prior gold standard) 44 and for PE, either spiral computed tomography of the chest 45 or ventilation/perfusion lung scan 46 (validated against the pulmonary angiogram, the prior gold standard). This diagnostic algorithm has not been specifically validated in the cancer population.…”

More on: venous thromboembolism and mortality after hip fracture: the ESCORTE study

“…Furthermore, the authors suggest that postoperative VTE is difficult to verify if venography is not performed; however, this invasive method is not commonly used in clinical practice and may be responsible for variability of interpretation according to the different observers [4]. Even though compression ultrasound (CUD) has less sensitivity for identifying asymptomatic deep vein thrombosis (DVT) [5][6][7], this technique has been validated as the firstline diagnostic test in suspected symptomatic DVT [8], for either postoperative or ambulatory patients [8,9] …”

“…The implemented diagnostic workup was insufficient to reach a conclusion in 27 of 76 cases of suspected PE; these were adjudicated as ÔpossibleÕ PEs. Ultrasonography used to confirm suspected DVT has limited sensitivity to distal vein thrombosis [7]. Both untested symptomatic patients and those diagnosed with possible PE were accounted for as being VTE-free in the analysis.…”