Duplex Scanning in Post-Operative Surgical Patients

Abstract

The technique of duplex scanning for the diagnosis of deep venous thrombosis (DVT) has been developed in 3 stages. Initially B-mode imaging with compression was used. Subsequently interrogation of the venous lumen using the Doppler facility was introduced and finally the latter became simple and efficient with the introduction of colour flow imaging. Sensitivities and specificities in excess of 90% have been produced for thrombosis proximal to the calf by all methods in symptomatic patients. Colour flow imaging has given the best results for calf DVT in symptomatic patients with 86% sensitivity and 91% specificity. Before the introduction of colour flow imaging the accuracy for the detection of old thrombi in asymptomatic patients was poor. With the introduction of colour, sensitivities and specificities in excess of 90% have been obtained for proximal DVT; for calf DVT, sensitivity of 79% and specificity of 97% have been reported by 2 studies. If further studies substantiate these recent results duplex scanning will become the non-invasive method to be used in screening asymptomatic patients.

Incidence of Deep Vein Thrombosis After Laparoscopic vs Minilaparotomy Cholecystectomy

“…Duplex scanning is noninvasive, and experienced examiners report only marginally inferior results for duplex scanning compared with venography for symptomatic cases, especially for femoropopliteal segment DVT. [46][47][48] Asymptomatic DVTs are mostly small, hemodynamically insignificant calf thromboses, however, which may be missed by duplex scanning even if color duplex is used. 49 Although the specificity of color duplex for the detection of asymptomatic below-knee thrombi is greater than 95% in some reports, 46,49,50 the sensitivity of this test for symptomless calf DVT ranges from only 33% to 88%.…”

“…[46][47][48] Asymptomatic DVTs are mostly small, hemodynamically insignificant calf thromboses, however, which may be missed by duplex scanning even if color duplex is used. 49 Although the specificity of color duplex for the detection of asymptomatic below-knee thrombi is greater than 95% in some reports, 46,49,50 the sensitivity of this test for symptomless calf DVT ranges from only 33% to 88%. 49,51 Even allowing for the possibility that the number of undiagnosed DVTs in this surveillance study was as many as 2 or 3 times the number diagnosed, laparoscopic and minilaparotomy cholecystectomy remain procedures with a low risk of thrombosis if the thromboprophylaxis measures used in this study are employed.…”

O papel do mapeamento dúplex no diagnóstico da trombose venosa profunda assintomática dos membros inferiores

“…Nicolaides & Kalodiki28 referiram que o uso da cor no MD poderia melhorar o diagnóstico em TVP assintomática, com base que, em pacientes sintomáticos, na TVP proximal, a sensibilidade passava de 91 para 97% e a especificidade, de 98 para 99%. Sugeriam que mais trabalhos deveriam ser feitos para comprovar esses resultados.…”

Deep venous thrombosis in postoperative vascular surgical patients: A frequent finding without prophylaxis

“…The absence of phasic Doppler signals with respiration, loss of brisk augmented signals, and incomplete or no filling of a vein with color or power Doppler ultrasound scanning were used as a means of supporting the diagnosis. 2,3 Patients were examined daily for signs of DVT or PE. Patients were treated appropriately with anticoagulation Most surgical patients should receive perioperative thromboprophylaxis in accordance with published recommendations.…”