Comparative value of tests for the diagnosis of venous thrombosis

Clinical Utility of Real-Time Compression Ultrasonography for Diagnostic Management of Patients with Recurrent Venous Thrombosis

In the diagnostic management of patients with clinically suspected recurrent deep-vein thrombosis (DVT), there are potential limitations to all available diagnostic techniques. Since venous abnormalities may persist for some time after an acute thrombosis, the usefulness of compression ultrasonography (US) for the detection of recurrent DVT may be jeopardized. We determined the rate of normalization of an abnormal compression US test of the popliteal and the common femoral veins in patients after a first episode of proximal DVT. In a cohort of 60 consecutive patients, the test result was normalized in only 29, 44, 54, and 60% of patients at 3, 6, 9, and 12 months, respectively. The investigation shows that for the detection of recurrent DVT of the leg, real-time compression US (using the single criterion of compression of the common femoral and popliteal vein) is of limited value. Future studies need to be performed, using more subtle interpretation of the compression US result, by quantifying the extent of residual thrombus, which may increase the usefulness of this test in patients with recurrent symptoms.

Prophylaxis Against Thromboembolism in Vascular Surgery

Thrombosis prophylaxis is indicated in vascular surgical patients for two general considerations: to prevent thromboembolism from the venous system and occlusion of reconstructed arterial vessels.

The purpose of this randomized, prospective study was to compare the effectiveness of low-dose heparin, heparin in combination with dihyder gotamine, and dextran-60 in the prevention of postoperative venous throm bosis and pulmonary embolism after vascular operations. In addition, any adverse effects of each medication on patency after arterial reconstruction was to be determined.

Emergency department use of hand-held Doppler ultrasonography

Doppler ultrasonography (DU) using a hand-held Doppler device represents a readily available emergency department (ED) technique that has been used for diagnostic testing with conditions associated with abnormal vascular flow, such as deep venous thrombosis, testicular torsion, and arterial insufficiency. DU may serve as a useful initial diagnostic test in the ED setting. The appropriate indications, techniques of examination, and accuracy of DU are summarized for the aforementioned conditions.

Early diagnosis of iliofemoral venous thrombosis by Doppler examination

The diagnosis of iliofemoral venous thrombosis prior to its progression to phlegmasia cerulea dolens can be difficult and, at times, confusing. The Doppler ultrasound examination in experienced hands can be extremely reliable and rapid in diagnosing the condition. During an 18 month period, we used the Doppler examination to diagnose iliofemoral venous thrombosis in 21 patients, 15 of whom had corroboration by venogram. The key to successful treatment and avoidance of significant complications was early and accurate diagnosis by the Doppler examination. No patient underwent operation or progressed to venous gangrene. Six were treated with streptokinase and the rest, with intravenous heparin, leg elevation, and stockings. We believe that iliofemoral venous thrombosis is a much more common disease than previously recognized and should be vigorously diagnosed and treated when a patient presents with a symptomatic extremity. The Doppler ultrasound examination represents a rapid, reliable alternative to the venogram in the early diagnosis of iliofemoral venous thrombosis.

Clinical studies with low-molecular-weight heparin(oid)s: an interim analysis

In this review an interim analysis was made of all clinical studies performed with low-molecular-weight heparin(oid)s (LMWH) up to January 1987. Thus far, many experimental studies on LMWH show these substances to have an increased benefit/risk ratio concerning efficacy and bleeding as compared to standard heparin. In man, this increased ratio was verified in some small open studies. However, until the present day, controversy still exists. Some of the difficulties in assessing the results of different investigations include the existence of various kinds of LMWH and the lack of a consensus as to the unitage in which they are expressed. Furthermore, no international agreement exists as to the test measuring dosage/effect and its standard. In the following review all published clinical studies were analyzed for patient groups. Important issues concerning controversy with regard to efficacy, bleeding risk, diagnosis, and testing are discussed. In general, it may be concluded that LMWH have an antithrombotic potential comparable to that of heparin, and that the benefit/risk ratio i.e., decreased bleeding potential when compared to standard heparin, as found in animal experiments, has not been clearly demonstrated in man.

The diagnosis of acute, recurrent, deep-vein thrombosis: a diagnostic challenge

Recurrent venous thrombosis presents a diagnostic challenge. Venography, impedance plethysmography and fibrinogen leg scanning all have potential limitations, and their role in this context has not been evaluated. We performed a prospective cohort study evaluating impedance plethysmography and leg scanning, plus venography, using outcome on long-term follow-up as the end point in 270 patients with clinically suspected recurrent deep-vein thrombosis. Anticoagulant treatment was withheld in the 181 patients negative by noninvasive testing and was given in patients positive by impedance plethysmography if leg scanning was positive or if intraluminal filling defects were detected by venography. The validity of this approach was tested by long-term follow-up. Three of 181 patients (1.7%) negative by noninvasive testing had a recurrence, compared with 18 of 89 (20%) with positive findings (p less than 0.001). Our objective diagnostic approach has high clinical utility; an objective rationale for withholding or giving treatment was established in 95% of patients.

Radionuclide venography as an outpatient screening test for deep venous thrombosis

This study evaluated the use of radionuclide venography (RNV) as a screening test for patients with signs and symptoms of deep venous thrombosis (DVT). Seventy patients underwent RNV; 27 of the 70 patients also had contrast venography. The incidence of DVT was 19% (13 of 70). RNV had an observed sensitivity of 93% and an observed specificity of 100%. Follow-up at one month revealed no evidence of thromboembolic disease in patients with a negative scan. RNV is an accurate, practical screening test for DVT.

Noninvasive detection and prevention of deep-vein thrombosis in the geriatric patient

Noninvasive methods for the early detection of, and prevention of deep-vein thrombosis can significantly reduce postoperative morbidity and mortality in the elderly due to venous thromboembolism. The technique of venous impedance plethysmography provides a rapid means of assessing the patency of the venous system by detecting changes in venous volume and maximum venous outflow, thus providing for early detection of deep-vein thrombosis. Prevention of deep-vein thrombosis can be accomplished through use of external intermittent pneumatic compression. This technique prevents venous stasis and stimulates the natural fibrinolytic activity of the vein-wall endothelium.