Strain gauge plethysmography for the detection of deep vein thrombosis

Department of Orthopaedic Surgery, Queen's University of Belfast, N. Ireland.
Journal of Biomedical Engineering 04/1993; 15(2):135-9. DOI: 10.1016/0141-5425(93)90043-X
Source: PubMed


Deep venous thrombosis is a widely recognized medical problem which results in significant morbidity and mortality. Venography is the current 'gold standard' diagnostic test for deep venous thrombosis; however it is costly, invasive and is unnecessarily performed in 50% of cases. This paper describes a self-contained, non-invasive system for automatic venous occlusion plethysmographic measurement and analysis. An examination of 274 symptomatic limbs was conducted using strain gauge plethysmography and a subsequent venographic examination was then performed. The plethysmographic results were then compared with venography so as to develop a means of discrimination for thrombotic and non-thrombotic limbs. Strain gauge plethysmography using the Belfast DVT Screener yielded a sensitivity of 100% and a sensitivity of 66.3% for proximal segment DVT. The efficacy of the discriminatory algorithm was then tested for the diagnosis of DVT in a further 101 symptomatic patients. A sensitivity of 94.7% and a specificity of 81.7% were observed for strain gauge plethysmography for proximal segment thrombosis in this patient group. The Belfast DVT Screener is highly sensitive for deep venous thrombosis and may be used to reduce the need for venography, which is of benefit to both the patient and clinician.

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    • "SGP was carried out in the admissions unit by one of the authors (BJR) who was blinded to the results of the d-dimer assay. The technique was carried out as described by Croal et al (1993). With the patient lying semi-recumbent, the leg was elevated and placed in a foot support with the knee flexed to a 90-degree bend. "
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    ABSTRACT: Suspicion of deep vein thrombosis (DVT) is a common reason for medical referral to hospital. Clinical signs and symptoms are notoriously unreliable, hence there is the need for objective testing. Strain gauge plethysmography (SGP) has been marketed as a technique for excluding lower limb DVT. We therefore set out to evaluate this screening tool. Over a 2 year period, 437 consecutive patients referred with suspected DVT were assessed using both plethysmography and Doppler ultrasound. When the two techniques were compared, plethysmography was found to have a negative predictive value of 90%. We conclude that strain gauge plethysmography has a role in the screening of patients with suspected DVT but should not be used as the sole method in patient assessment.
    Full-text · Article · Sep 2002 · British Journal of Haematology
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    ABSTRACT: This study compares the results of a computerized strain-gauge plethysmograph with ascending lower limb venography in 94 patients with clinical deep venous thrombosis, and in 121 patients with asymptomatic legs being screened after total hip replacement. In the symptomatic patients, strain-gauge plethysmography had a sensitivity of 100%, an accuracy of 73%, a specificity of 64% and a negative predictive value of 100% for thrombosis above the popliteal confluence. In the screened patients, the figures were 38.1%, 55.4%, 60.0% and 81.1% respectively. Computerized strain-gauge plethysmography is a safe, non-invasive, reliable and portable method of excluding proximal thrombosis in a symptomatic patient. It avoids the need for urgent venography when anticoagulation therapy is reserved for those with proximal thrombosis. The device was not valuable as a screening tool after total hip replacement, since it had a low specificity and did not reliably detect the non-occlusive mural femoral thrombi which typically follow this procedure.
    No preview · Article · Nov 1994 · British Journal of Radiology
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    ABSTRACT: Because clinical signs and symptoms are unreliable the diagnosis of deep vein thrombosis (DVT) should be objectified. Advantages and disadvantages of contrast venography, plethysmography, ultrasound techniques, fibrinogen leg scanning, computer-assisted tomography, magnetic resonance imaging and blood tests are discussed. In patients with a first event of suspected DVT non-invasive methods like serial plethysmography or ultrasound testing are sensitive and specific enough to make a treatment decision. It is safe to withhold anticoagulants if the test remains normal within 1 week. In patients with suspected recurrent DVT new non-invasive techniques are being tested, but up to now the definitive objective diagnostic test continues to be contrast venography. In first period as well as in recurrent DVT D-Dimer testing could be an additional test to exclude active thromboembolism.
    Full-text · Article · Apr 1996 · The Netherlands Journal of Medicine
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