Transmitted cardiac pulsations as an indicator of transjugular intrahepatic portosystemic shunt function: initial observations

Identification of the Most Important Subset of Doppler, Laboratory, and Clinical Parameters for Serial TIPS Evaluation

OBJECTIVE. The purpose of the present study was to identify the subset of a wide range of serial Doppler, laboratory, and clinical parameters most predictive (both individually and in combination) of TIPS dysfunction in a large patient sample. MATERIALS AND METHODS. The medical records of 189 patients who had undergone TIPS procedures were analyzed. The patients (mean age, 52 years; 62% of whom were men) had undergone 1139 Doppler studies and 323 portovenograms. Laboratory parameters included model for end-stage liver disease (MELD) scores, serum albumin levels, presence of ascites, and time since last intervention. Doppler parameters included intrashunt velocities, temporal change in intrashunt velocities, main portal vein velocity, direction of flow in the left portal hepatic vein, and venous pulsatility index. Statistical analysis used ROC, univariate, and multivariate regression models to assess the parameters both individually and in combination. Shunt dysfunction was defined by a portosystemic gradient of more than 12 mm Hg. RESULTS. The laboratory and clinical parameters of greatest predictive value included the MELD score and the time since the last intervention. The Doppler parameters that were of greatest predictive value included the change in velocity at the hepatic venous end and the left portal vein flow direction. Multivariate models produced an AUC of 0.74. Differences between functional and dysfunctional shunts were also statistically significant for absolute velocity at the hepatic venous end, the change in velocity within the stent, and the temporal change in the mid shunt velocity. CONCLUSION. The subset of serial parameters most predictive of TIPS dysfunction are the temporal change in the velocity at the hepatic venous end, the absolute velocity at the hepatic venous end, the direction of flow in the left portal venous branch, and changes in the MELD score.

Evaluation of Doppler-ultrasonography in the diagnosis of transjugular intrahepatic portosystemic shunt dysfunction: A prospective study

AIM

To prospectively evaluate the performance of Doppler-ultrasonography (US) for the detection of transjugular intrahepatic portosystemic shunt (TIPS) dysfunction within a multicenter cohort of cirrhotic patients.

METHODS

This study was conducted in 10 french teaching hospitals. After TIPS insertion, angiography and liver Doppler-US were carried out every six months to detect dysfunction (defined by a portosystemic gradient ≥ 12 mmHg and/or a stent stenosis ≥ 50%). The association between ultrasonographic signs and dysfunction was studied by logistic random-effects models, and the diagnostic performance of each Doppler criterion was estimated by the bootstrap method. This study was approved by the ethics committee of Tours.

RESULTS

Two hundred and eighteen pairs of examinations performed on 87 cirrhotic patients were analyzed. Variables significantly associated with dysfunction were: The speed of flow in the portal vein (P = 0.008), the reversal of flow in the right (P = 0.038) and left (P = 0.049) portal branch, the loss of modulation of portal flow by the right atrium (P = 0.0005), ascites (P = 0.001) and the overall impression of the operator (P = 0.0001). The diagnostic performances of these variables were low; sensitivity was < 58% and negative predictive value was < 73%. Therefore, dysfunction cannot be ruled out from Doppler-US.

CONCLUSION

The performance of Doppler-US for the detection of TIPS dysfunction is poor compared to angiography. New tools are needed to improve diagnosis of TIPS dysfunction.

Volumetric blood flow in transjugular intrahepatic portosystemic shunt revision using 3-dimensional Doppler sonography

OBJECTIVES

Three-dimensional (3D)/4-dimensional (4D) sonographic measurement of blood volume flow in transjugular intrahepatic porto systemic shunt revision with the intention of objective assessment of shunt patency.

METHODS

A total of 17 patients were recruited (12 male and 5 female; mean age, 55 years; range, 30-69 years). An ultrasound system equipped with a 2.0-5.0-MHz probe was used to acquire multivolume 3D/4D color Doppler data sets to assess prerevision and postrevision shunt volume flow. Volume flow was computed offline based on the principle of surface integration of Doppler-measured velocity vectors in a lateral-elevational c-surface positioned at the color flow focal depth (range, 8.0-11.5 cm). Volume flow was compared to routine measurements of the prerevision and postrevision portosystemic pressure gradient. Prerevision volume flow was compared with the outcome to determine whether a flow threshold for revision could be defined.

RESULTS

Linear regression of data from revised transjugular intrahepatic portosystemic shunt cases showed an inverse correlation between the mean-normalized change in prerevision and postrevision shunt volume flow and the mean-normalized change in the prerevision and postrevision portosystemic pressure gradient (r(2) = 0.51; P = .020). Increased shunt blood flow corresponded to a decreased pressure gradient. Comparison of prerevision flows showed preliminary threshold development at 1534 mL/min, below which a shunt revision may be recommended (P = .21; area under the receiver operating characteristic curve = 0.78).

CONCLUSIONS

Shunt volume flow measurement with 3D/4D Doppler sonography provides a potential alternative to standard pulsed wave Doppler metrics as an indicator of shunt function and predictor of revision.

Diagnostic radiology of transjugular intrahepatic portosystemic shunts

Transjugular intrahepatic portosystemic shunts (TIPS) are an effective method for treating the complications of portal hypertension. Specific indications for TIPS include secondary prevention of variceal bleeding and refractory ascites. The purpose of this review is to summarize the role of diagnostic radiology in the creation and assessment of TIPS, to highlight the complications that can occur post-TIPS, and to critically evaluate the literature regarding ultrasound evaluation of TIPS.

Parâmetros dopplervelocimétricos na avaliação da perviedade da anastomose portossistêmica intra-hepática transjugular (TIPS)

A anastomose portossistêmica intra-hepática transjugular (TIPS) é um procedimento intervencionista minimamente invasivo realizado pela introdução de prótese metálica auto-expansível no parênquima hepático, via transjugular. Tem por objetivo tratar as complicações da hipertensão portal, principalmente a hemorragia digestiva alta e a ascite refratária. A estenose é complicação freqüente, embora o procedimento seja eficaz e com baixo índice de insucesso. O diagnóstico precoce da estenose é de fundamental importância, pois interfere no tipo de tratamento a ser realizado e o reaparecimento dos sintomas pode ser grave. O ultra-som Doppler é então utilizado para o seguimento dos pacientes portadores do TIPS, e vários parâmetros são descritos na literatura para o diagnóstico de estenose, como: as velocidades mínima e máxima no interior da prótese, a velocidade na veia porta, o gradiente de velocidade entre dois pontos da prótese, e outros. Infelizmente não há consenso sobre qual parâmetro ou conjunto de parâmetros é mais eficaz no diagnóstico, porque os protocolos de avaliação variam de instituição para instituição. Os autores realizaram uma revisão dos parâmetros de estenose descritos na literatura e de outros aspectos de fundamental importância na compreensão do procedimento, como as indicações, as contra-indicações e a fisiopatologia da estenose.

Parâmetros dopplervelocimétricos na avaliação da perviedade da anastomose portossistêmica intra-hepática transjugular (TIPS): estudo prospectivo

OBJETIVO: Estudar as alterações hemodinâmicas consideradas normais após a realização da anastomose portossistêmica intra-hepática transjugular (TIPS) e a eficácia dos parâmetros sugestivos de estenose do TIPS com o ultra-som Doppler. MATERIAIS E MÉTODOS: Dezesseis pacientes foram avaliados de maneira prospectiva, no período de dezembro de 2001 a março de 2003. As avaliações foram realizadas 24-48 horas após o TIPS e a seguir em intervalos regulares de 30 dias, três meses, seis meses e um ano, com ultra-som modo B, Doppler pulsado, Doppler colorido e de amplitude em diferentes pontos da prótese relacionados ao TIPS. A angiografia foi realizada apenas para a confirmação dos resultados e terapêutica pertinente. RESULTADOS: Até o momento apenas os achados de fluxo contínuo no terço proximal da prótese e o gradiente de velocidade entre dois pontos da prótese apresentaram significância estatística para o diagnóstico de estenose do TIPS (p < 0,001), mas outros diferentes critérios também estiveram presentes, porém sem significância estatística. CONCLUSÃO: O ultra-som Doppler é uma ferramenta eficaz no diagnóstico da perviedade e das complicações secundárias à realização do TIPS, sobretudo da estenose. No entanto, é necessária casuística maior, a fim de determinar um conjunto de parâmetros que facilite o seguimento destes pacientes, reservando a angiografia apenas para o tratamento pertinente.

Doppler Ultrasound Evaluation of Transjugular Intrahepatic Portosystemic Shunt Function

The current literature reflects controversy regarding the accuracy of Doppler ultrasound for the detection of transjugular intrahepatic portosystemic shunt (TIPS) malfunction. Experience has revealed many pitfalls and artifacts that can potentially interfere with the proper performance and interpretation of Doppler studies in patients with TIPS. In this article the author discusses and illustrates the spectrum of pitfalls that may be encountered during Doppler evaluation of TIPS function.

Doppler evaluation of transjugular intrahepatic portosystemic shunts

Transjugular intrahepatic portosystemic shunts are becoming an increasingly popular technique for the treatment of portal hypertension and its complications. However, to maintain patency, revisions are periodically required to treat stenosis and thrombosis. At many centers, Doppler sonography is used for routine follow-up. A variety of hemodynamic parameters, including main portal vein velocity, maximum stent velocity, minimum stent velocity, velocity gradient in the stent, temporal changes in stent velocity, flow direction in the intrahepatic portal and hepatic veins, and pulsatility of flow in the stent can be used. Many studies have confirmed that Doppler sonography is a valuable, noninvasive means of detecting stent malfunction, although the criteria vary somewhat at different institutions.

Current use of transjugular intrahepatic portosystemic shunts

The principal indication for transjugular intrahepatic portosystemic shunts (TIPS) continues to be rescue therapy for variceal hemorrhage that cannot be controlled by endoscopic or medical therapy. TIPS provide no survival advantage in prevention of rebleeding or refractory ascites. The indications for TIPS continue to expand, however, especially for Budd-Chiari syndrome and hydrothorax. Other more novel indications include bleeding portal hypertensive gastropathy or ectopic varices, Budd-Chiari syndrome, veno-occlusive disease, hepatorenal syndrome, hepatopulmonary syndrome, hepatocellular carcinoma, and polycystic liver disease. Great strides have been made recently in models to predict mortality and complications following TIPS placement. Graft stents hold promise based on early studies. Finally, complications are common and may be life threatening.