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Doppler Ultrasound Lab Report

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appear similar to conventional stents.”8 Middleton, Teefey and Darcy8 note that the use of PFTE endografts will likely become standard as their performance outweighs the early stent materials used. Color Doppler as well as pulsed Doppler should be used to interrogate the stent and supporting vessels. Velocity measurements are taken using angle correct and spectral waveforms are recorded. Careful examination of the liver vasculature is imperative to verify proper stent function. Specifically, thrombosis or occlusion can be assessed with color and Doppler ultrasound. Velocity parameters may vary from patient to patient and also will change from immediate post procedure velocities to those obtained during long term follow up. Universal Doppler…show more content…
The study hoped to find an acceptable correlation with abnormal or normal Doppler ultrasound and venography. The results were not sufficient to determine that Doppler ultrasound alone was an adequate tool to determine stent malfunction consistently. Future objectives are for non-invasive Doppler testing to be sensitive and reproducible enough to detect early stent malfunction even before symptoms occur.29 Boyer,23 reports that Doppler ultrasound has sensitivity and specificity rates from 70%-100% in cases of stent stenosis, but it is still not ideal. Ultrasound requires a technologist and radiologist with experience and must be conducted with consistent parameters to obtain dependable results. Most of the trials recommend follow up studies including some or all of the following: venography, Doppler ultrasound combined with two-dimensional ultrasound, angiography, magnetic resonance imaging and computerized…show more content…
According to Middleton, Teefey and Darcy,8 TIPS placement is successful in about 90% of patients, but does hold a complication rate of 10-16%. Research has shown that placement of TIPS as a secondary treatment for variceal bleeding has produced encouraging results. In 13 random clinical trials, including over 900 patients, recurrent variceal bleeding rates were 9-40%, which is superior to endoscopic treatments that have recurrent bleeding rates from 20-60%. This success rate has made TIPS procedures more utilized in the setting of variceal bleeding. Additionally, the same clinical trials indicate that ascites reduction after shunting ranges from 38-84%, which is favorable to large volume paracentesis that reported rates of 0-43%. “Compared with large-volume paracentesis, TIPS improved transplant-free survival and the incidence of recurrent ascites in cirrhotic patients with refractory ascites.”26 There is evidence of an increase in the development of HE in patients who undergo TIPS, whereas endoscopic treatment does not show an increase. Furthermore, HE is twice as likely to occur when paracentesis is performed. An important consideration is that the complication rate for hepatic encephalopathy does increase with TIPS usage whereas it doesn’t with endoscopic treatment and it is twice as likely to occur as when paracentesis is performed.28 Presently, TIPS is often used as a temporary solution for patients who are
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