Long-term follow-up after TIPS: use of Doppler velocity criteria for detecting elevation of the portosystemic gradient

Use of doppler ultrasound to predict need for transjugular intrahepatic portosystemic shunt revision

BACKGROUND

Transjugular intrahepatic portosystemic shunt (TIPS) is used to treat complications of portal hypertension, such as ascites and variceal bleeding (VB). While liver doppler ultrasound (DUS) is used to assess TIPS patency, trans-shunt venography (TSV) is the gold standard.

AIM

To determine the accuracy of DUS to assess TIPS dysfunction and for need for revision.

METHODS

Retrospective review of patients referred for TIPS revision from 2008-2021. Demographics, DUS parameters at baseline and at the DUS preceding TIPS revision, TSV data were collected. Receiver operating characteristics curves, sensitivity, specificity, performance for doppler to predict need for revision were performed. Univariate and multivariate analyses were used to predict clinical factors associated with need for TIPS revision.

RESULTS

The cohort consisted of 89 patients with cirrhosis (64% men, 76% white, 31% alcohol as etiology); median age 59 years. Indication for initial TIPS were VB (41%), refractory ascites (51%), and other (8%). TIPS was revised in 44%. On univariate analysis, factors associated with need for TIPS revision were male (P = 0.03), initial indication for TIPS (P = 0.05) and indication for revision (P = 0.01). Revision of TIPS was associated with lower mortality (26% vs 46%) and significantly lower rates of transplant (13% vs 24%; P = 0.1). In predicting need for TIPS revision, DUS has a 40% sensitivity, 45% specificity, PPV 78%, and NPV 14%. The most accurate location for shunt velocity measure was distal velocity (Area under the curve: 0.79; P = 0.0007).

CONCLUSION

DUS has poor overall sensitivity and specificity in predicting need for TIPS revision. Non-invasive methods of predicting TIPS dysfunction are needed since those needing TIPS revision had better survival.

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.

Performance of ultrasound for detection of transjugular intrahepatic portosystemic shunt dysfunction: a meta-analysis

PURPOSE

Although ultrasound has been widely used to evaluate transjugular intrahepatic portosystemic shunts (TIPS) patency, several studies have reported conflicting data regarding its performance. Therefore, we aimed to evaluate performance of ultrasound for detection of TIPS dysfunction by performing a meta-analysis.

METHODS

Literature search was performed for studies evaluating ultrasound for TIPS dysfunction, stenosis, and occlusion using PubMed, EMBASE, Scopus, and Cochrane Library through February 2019. Pooled sensitivity, specificity, log diagnostic odds ratio (LDOR), and area under curve (AUC) of summary receiver-operating characteristic were calculated. Subgroup analyses were performed according to ultrasonographic criteria and type of stent.

RESULTS

In total, 21 studies were evaluated. Pooled sensitivity, specificity, and LDOR of ultrasound for detection of TIPS dysfunction were 0.82 (0.67, 0.93), 0.58 (0.46, 0.70), and 1.77 (1.20, 2.35). Pooled sensitivity, specificity, and LDOR for TIPS stenosis were 0.80 (0.69, 0.90), 0.80 (0.69, 0.91), and 2.83 (1.88, 3.78). Pooled sensitivity, specificity, and LDOR for TIPS occlusion were 0.96 (0.92, 0.99), 1 (0.99, 1.00), and 6.28 (4.96, 7.60). AUCs of ultrasound for TIPS dysfunction, stenosis, and occlusion were 0.77, 0.86, and 0.95, respectively.

CONCLUSIONS

Although ultrasound had excellent performance for TIPS occlusion and acceptable performance for TIP stenosis, most studies utilized bare metal stent, and therefore, application to current practice is limited. Ultrasound for TIPS dysfunction in the setting of covered metal stent appeared to have acceptable sensitivity of 0.82, but limited specificity of 0.58 and low LDOR of 1.77. A new noninvasive tool is needed for detection of TIPS dysfunction in the era of covered metal stent.

Shear wave elastography prior to transjugular intrahepatic portosystemic shunt may predict the decrease in hepatic vein pressure gradient

BACKGROUND

Transjugular intrahepatic portosystemic shunt (TIPS) is a procedure used to treat portal hypertension complications. Our aim was to evaluate liver and spleen stiffness measurement (LSM and SSM, respectively) changes using acoustic radiation force impulse imaging (ARFI) in comparison to Child-Pugh scores for predicting hepatic venous pressure gradient (HVPG) decreases after TIPS implantation.

METHODS

This prospective study included 31 consecutive clinically significant portal hypertension patients with TIPS indication. All patients received LSM and SSM before TIPS, at baseline, 2 days (follow-up 1) and 6 weeks (follow-up 2) post-implantation. HVPG was performed during the TIPS procedure.

RESULTS

The mean decrease in HVPG after TIPS was 63%. LSM and SSM decreased significantly between baseline and follow-up 2 (p < 0.001 and p < 0.001, respectively). At baseline, follow-up 1 and follow-up 2, significant correlations were detected between mean SSM and mean HVPG (p = 0.026; p = 0.018; p = 0.002, respectively). HVPG decreased to ≤ 10 mmHg in 61% of patients for which LSM, SSM, and Child-Pugh score were predictors (p = 0.033, p = 0.002 and p = 0.030, respectively). The area under the curve (AUC) for LSM, SSM, and Child-Pugh was 0.88, 0.90, and 0.84, respectively, with close sensitivity and specificity. SSM had the highest diagnostic accuracy for predicting an HVPG decrease to ≤ 10 mmHg in comparison to LSM and Child-Pugh score.

CONCLUSION

Spleen stiffness is superior to liver stiffness and Child-Pugh score as a non-invasive surveillance tool for evaluating patients with clinically significant portal hypertension (HVPG ≥ 10 mmHg) prior to TIPS.

Longitudinal Monitoring of Hepatic Blood Flow before and after TIPS by Using 4D-Flow MR Imaging

Purpose To demonstrate the feasibility of four-dimensional (4D)-flow magnetic resonance (MR) imaging for noninvasive longitudinal hemodynamic monitoring of hepatic blood flow before and after transjugular intrahepatic portosystemic shunt (TIPS) placement. Materials and Methods The institutional review board approved this prospective Health Insurance Portability and Accountability Act compliant study with written informed consent. Four-dimensional-flow MR imaging was performed in seven patients with portal hypertension and refractory ascites before and 2 and 12 weeks after TIPS placement by using a time-resolved three-dimensional radial phase-contrast acquisition. Flow and peak velocity measurements were obtained in the superior mesenteric vein (SMV), splenic vein (SV), portal vein (PV), and the TIPS. Flow volumes and peak velocities in each vessel, as well as the ratio of in-stent to PV flow, were compared before and after TIPS placement by using analysis of variance. Results Flow volumes significantly increased in the SMV (0.24 L/min; 95% confidence interval [CI]: 0.07, 0.41), SV (0.31 L/min; 95% CI: 0.07, 0.54), and PV (0.88 L/min; 95% CI: 0.06, 1.70) after TIPS placement (all P < .05), with no significant difference between the first and second post-TIPS placement acquisitions (all P > .11). Ascites resolved in six of seven patients. In those with resolved ascites, the TIPS-to-PV flow ratio was 0.8 ± 0.2 and 0.9 ± 0.2 at the two post-TIPS time points, respectively, while the observed ratios were 4.6 and 4.3 in the patient with refractory ascites at the two post-TIPS time points, respectively. In this patient, 4D-flow MR imaging demonstrated arterio-portal-venous shunting, with draining into the TIPS. Conclusion Four-dimensional-flow MR imaging is feasible for noninvasive longitudinal hemodynamic monitoring of hepatic blood flow before and after TIPS placement. ^© RSNA, 2016 Online supplemental material is available for this article.

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.

Covered transjugular intrahepatic portosystemic shunts: accuracy of ultrasound in detecting shunt malfunction

OBJECTIVE

The purpose of this study was to determine the accuracy of ultrasound for detecting transjugular intrahepatic portosystemic shunt (TIPS) malfunction in covered stents in comparison with bare metal stents.

MATERIALS AND METHODS

During a 6-year period, 126 TIPS angiography examinations were performed in 78 patients who had undergone a recent TIPS ultrasound examination. Radiology reports and images were retrospectively reviewed, and the sensitivity and specificity of sonographic parameters for detecting TIPS dysfunction were calculated using TIPS angiography and portosystemic gradient as the reference standards.

RESULTS

Of 126 paired studies, 43 were in bare metal TIPS and 83 were in covered TIPS. Peak shunt velocity of covered and bare metal TIPS measured by ultrasound showed comparable sensitivities for detection of shunt dysfunction, using both depressed (< 90 cm/s) and elevated (> 200 cm/s) peak shunt velocity criteria. However, a depressed velocity was more specific in covered TIPS (0.939 vs 0.550, p < 0.001) whereas elevated velocity was more specific in bare TIPS (0.485 vs 0.800, p = 0.041). An interval change in peak TIPS velocity greater than 25% was significantly more sensitive in detection of dysfunction in covered TIPS (0.815 vs 0.400, p = 0.015) whereas detection based on main portal vein velocities (≤ 30 cm/s) was not statistically different in the two groups.

CONCLUSION

Our data suggest that the accuracy of ultrasound for detection of TIPS shunt malfunction is at least as high in covered stents as in bare metal stents. Diagnostic performance for several sonographic parameters varied significantly between bare and covered stents, suggesting the need for optimization of sonographic criteria for covered stents.

Changes in portal hemodynamics after TIPS in liver cirrhosis and portal hypertension

OBJECTIVE

The objective of this study is to analyze the changes in portal hemodynamics that occurs in portal hypertension before and after transjugular intrahepatic portosystemic shunt (TIPS), to investigate the relationship between these changes and portal pressure (PP) and to determine the significance of sonographic parameters in measuring PP.

METHODS

Ultrasonography of the portal and splenic veins and direct measurement of the PP were performed in 92 patients before and after TIPS. The differences observed in the portal and splenic vein diameters, the blood flow velocity in the portal and splenic veins and the PP were measured, and the correlations between PP and the other parameters were assessed using the SPSS 13 (SPSS Inc., Chicago, IL, USA). P < 0.05 was considered statistically significant.

RESULTS

We observed a significant decrease in the PP and the diameters of the portal and splenic veins compared to preoperative conditions (p < 0.001). The velocity of blood flow in the portal and splenic veins was significantly increased after TIPS (p < 0.001). The PP correlated with the diameter and velocity of blood flow in portal (r = 0.46, p = 0.020; r = 0.47, p = 0.017) and splenic vein (r = 0.57, p = 0.003; r = 0.33, p = 0.003) only in Child's A and was absent in Child's B cirrhosis patients.

CONCLUSION

The PP is influenced by the complex interaction between intrahepatic vascular resistance, collaterals and the amount of portal blood flow, which varies considerably between individuals. Once a certain pressure threshold is reached, collaterals form, and the correlation between the ultrasonographic parameters and PP becomes limited.

Doppler US of the liver made simple

Doppler ultrasonography (US) is usually the first-line modality for evaluating flow in native liver vessels and transjugular intrahepatic portosystemic shunts (TIPS). Waveforms, which represent flow in each of the major vessels and in TIPS, have been well described. The appearance of these waveforms should be recognized, and the mechanisms behind their generation should be understood by those interpreting these examinations. Understanding how waveforms are formed--that is, their mechanisms for generation--is predicated on knowing basic vascular Doppler concepts and established nomenclature. This article is a review of these basic concepts and nomenclature as applied to the interpretation of liver Doppler US waveforms.

Transcatheter local thrombolysis in patients with extensive TIPS thrombosis

BACKGROUND

Transcatheter local thrombolytic therapy in patients with portosplanchnic venous thrombosis has been used in few cases.

CASE REPORTS

Here, we present our single-center experience with transcatheter thrombolytic therapy in three patients with extensive refractory portal and transjugular intrahepatic portosystemic shunt (TIPS) thrombosis. Thrombolytic therapy was successful for all three patients. Two patients developed minor procedure-related bleeding.

CONCLUSION

Local thrombolysis could be proposed in case of TIPS thrombosis for patients in whom the venous flow cannot be restored by using conventional anticoagulant therapy and stent mechanical revision.

Comparison study of Doppler ultrasound surveillance of expanded polytetrafluoroethylene-covered stent versus bare stent in transjugular intrahepatic portosystemic shunt

OBJECTIVE

This prospectively randomized controlled study aimed to assess with Doppler ultrasound (US) the shunt function of expanded polytetrafluoroethylene (ePTFE)-covered transjugular intrahepatic portosystemic shunt (TIPS) stent versus bare stent and to evaluate the usefulness of routine TIPS follow-up of ePTFE-covered stents.

METHODS

Sixty consecutive patients were randomized for bare or covered transjugular TIPS stenting in our institution between April 2007 and April 2009. Data of follow-up Doppler US, angiography, and portosystemic pressure gradient measurements were collected and analyzed.

RESULTS

The follow-up period was 8.34 + or - 4.42 months in the bare-stent group and 6.16 + or - 3.89 months in the covered-stent group. Baseline clinical characteristics were similar in both groups. Two hundred three US studies were performed in 60 patients, with a mean of 3.4 per patient, and demonstrated abnormalities in 28 patients (21 bare stents, 7 ePTFE-covered stents), 19 of them (13 in bare-stent group, 6 in covered-stent group) showing no clinical evidence of recurrence. Ten of 13 patients in the bare-stent group underwent balloon angioplasty or additional stent placement, whereas only one of six patients in the covered-stent group needed reintervention for intimal hyperplasia. The average peak velocity in the midshunt of ePTFE-covered stent was 139 + or - 26 cm/s after TIPS creation and 125 + or - 20 cm/s during follow-up, which was significantly higher than the bare-stent group (p < 0.05). The main portal vein and hepatic artery showed higher flow velocities in the ePTFE-covered stent group than in the bare-stent group. ePTFE-covered stents maintained lower portosystemic pressure gradient than bare stents (9.5 + or - 2.9 versus 13.2 + or - 1.5 mmHg, p < 0.05).

CONCLUSIONS

ePTFE-covered stents resulted in higher patency rates and better hemodynamics than bare stents. Routine US surveillance may not be necessary in patients with ePTFE-covered TIPS stent.

TIPS thrombosis related to abdominal trauma

Abdominal trauma is a very rare cause of portal vein thrombosis. A 47-year-old woman presenting alcoholic cirrhosis was referred to our institution for refractory ascites. A transjugular intrahepatic portosystemic shunt (TIPS) was placed in October 2008 and the immediate post-operative course was uneventful. The efficiency of the TIPS was regularly checked by Doppler ultrasonography disclosing the complete regression of ascites and the patency of the stent. In February 2009, she was readmitted for recurrence of ascites. One week before admission, the patient reported a fall of a ladder with severe abdominal trauma and pain. The abdominal computed tomography scan showed thrombosis of the portal system extending from the spleno-mesenteric confluence to the portal vein. A mechanical revision of TIPS was realised, associated with local thrombolytic therapy. The clinical course was favourable and the efficiency of the TIPS was therefore regularly checked by Doppler ultrasonography disclosing the complete regression of ascites and the patency of the stent. Exhaustive search of an underlying thrombophilic state was performed to explain the occurrence of extensive portal thrombosis in our patient and identified a protein C deficiency. In conclusion, we report the first case of a patient who presented a TIPS and extensive portal and TIPS thrombosis probably because of an abdominal trauma. Biological screening identified an inherited protein C deficiency, which supports a recent notion that portal vein thrombosis most often occurs when both the local and the systemic aetiological factors are combined.

The transjugular intrahepatic portosystemic shunt (TIPS)

The creation of an intrahepatic portosystemic shunt via a transjugular approach (TIPS) is an interventional radiological procedure used to treat the complications of portal hypertension. TIPS insertion is principally indicated to prevent or arrest variceal bleeding when medical or endoscopic treatments fail, and in the management refractory ascites. This review discusses the development and execution of the technique, with focus on its clinical efficacy. Patient selection, imaging surveillance, revision techniques, and complications are also discussed.

Role of ultrasound surveillance of transjugular intrahepatic portosystemic shunts in the covered stent era

PURPOSE

To assess ultrasound (US) surveillance of expanded polytetrafluoroethylene (ePTFE)-covered stents in transjugular intrahepatic portosystemic shunts (TIPS).

MATERIALS AND METHODS

Procedural data, including stent size and portosystemic gradients (PSG) before and after creation of TIPS, were obtained retrospectively in 55 patients (33 men, 22 women). Chart review provided clinical information, including etiology of liver disease, indication for TIPS creation, and Child-Pugh class. Radiology reports provided US venography data and pathology reports confirmed shunt status in transplant recipients. Patients had baseline US examinations 3-7 days after TIPS creation with scheduled follow-up at 1, 3, 6, and 12 months after the procedure. Clinical and radiology reports were compared to evaluate US surveillance of Viatorr stents.

RESULTS

One hundred fifty-nine US examinations were performed on 52 patients, for an average 3.1 studies per patient (range, 1-7) over a mean follow-up duration of 173 days (range, 0-1,013 d). Sixty-four US studies (40%) were baseline studies, 88 studies (55%) were routine follow-up studies, and seven (4%) were interval studies. US predicted TIPS abnormalities in 30 of 159 studies (19%); venography followed 15 of 30 abnormal US findings (50%) and clinical examinations complemented 10 of 15 venograms (67%). Venography and US were concordant in eight of 15 paired studies (53%); clinical examinations, when conducted, accurately predicted shunt status in all but one case. US findings changed management in six of 159 studies (4%): five of six (83%) were baseline evaluations and the other one (17%) was a routine follow-up examination. A total of five baseline US examinations (8%) and one surveillance examination (1%) altered patient management.

CONCLUSIONS

A single US examination after a TIPS procedure to confirm immediate function may be valuable, but routine US is not effective for long-term surveillance of ePTFE-covered stents.

Clinical evaluation of magnetic resonance imaging flowmetry of portal and hepatic veins in patients following hepatectomy

BACKGROUND

Hepatic blood flow was associated with degree of hepatic damage. Measurements of blood flow using ultrasonography (US) may vary due to any observer's and patient's conditions. The utility of magnetic resonance imaging (MRI) flowmetry in portal and hepatic veins was assessed.

PATIENTS AND METHODS

Using the phase-contrast method, the mean flow velocity of portal (PVF) and hepatic vein (HVF) were determined by MRI and US in 75 consecutive patients with liver diseases, including 58 patients undergoing hepatectomy. The correlations between these parameters and clinicopathological findings were examined.

RESULTS

PVF and HVF measured by MRI flowmetry were 12.8+/-4.5 and 14.7+/-5.3 cm/s, respectively. There was no significant correlation of both flows between MRI and US. PVF correlated significantly with portal pressure (r = -0.722; P < 0.05). There was a negative correlation between HVF and histological activity index score (r = -0.366; P < 0.05). PVF and HVF were lower in patients with cirrhosis and higher staging score (2-4) and PVF was lower in patients with higher grading score (2-3; P < 0.05). PVF and HVF were not significantly associated with postoperative complications.

CONCLUSIONS

Our results suggest that MRI flowmetry is a potentially useful tool for measurement of hepatic blood flow and recommend its use for estimation of liver cirrhosis-associated impairment.

Utility of color Doppler ultrasonography predicting tips dysfunction

OBJECTIVES

Color Doppler ultrasonography (CDUS) has been proposed as an alternative to portal pressure gradient (PPG) measurement to detect transjugular intrahepatic portosystemic shunt (TIPS) dysfunction but with inconsistent results. This study aimed at developing and validating CDUS criteria to assess TIPS dysfunction.

METHODS

A total of 117 consecutive follow-up simultaneous CDUS and hemodynamic evaluations in 34 patients with TIPS were analyzed. TIPS dysfunction was defined as a PPG >12 mmHg. A predictive model was obtained with logistic regression and was validated in an independent, prospective sample of 119 consecutive paired CDUS/hemodynamic evaluations in 55 patients.

RESULTS

TIPS dysfunction was present in 57 of the 117 studies in the retrospective series. At multivariate analysis, mean maximum flow velocity at the portal vein (mVPmax) and direction of flow in the intrahepatic portal vein branches (FD) were the only independent predictors of TIPS dysfunction. The prediction rule for TIPS dysfunction derived from the model (mVPmax <28 cm/s when flow is hepatofugal or mVPmax <39 cm/s when flow is hepatopetal) had 90% sensitivity, 45% specificity, and negative likelihood ratio of 0.23. This prediction rule was validated both in patients with bare stents and in patients with polytetra fluoroethylene (PTFE)-covered stents, showing an overall 87% sensitivity, 57% specificity, and 0.23 negative likelihood ratio.

CONCLUSIONS

The combination of two CDUS parameters correlate with TIPS dysfunction with high sensitivity and low specificity but with a good negative likelihood ratio. TIPS catheterization can be safely avoided in half of the patients using this predictive rule.

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.

Transjugular intrahepatic portosystemic shunt

The transjugular intrahepatic portosystemic shunt (TIPS) is an interventional treatment resulting in decompression of the portal system by creation of a side-to-side portosystemic anastomosis. Since its introduction 16 years ago, more than 1,000 publications have appeared demonstrating broad acceptance and increasing clinical use. This review summarizes our present knowledge about technical aspects and complications, follow-up of patients and indications. A technical success rate near 100% and a low occurrence of complications clearly depend on the skills of the operator. The follow-up of the TIPS patient has to assess shunt patency, liver function, hepatic encephalopathy and the possible development of hepatocellular carcinoma. Shunt patency can best be monitored by duplex sonography and can avoid routine radiological revision. Short-term patency may be improved by anticoagulation, while such a treatment does not influence long-term patency. Stent grafts covered with expanded polytetrafluoroethylene show promising long-term patency comparable with that of surgical shunts. With respect to the indications of TIPS, much is known about treatment of variceal bleeding and refractory ascites. The thirteen randomized studies that are available to date show that survival is comparable in patients receiving TIPS or endoscopic treatment for acute or recurrent variceal bleeding. Another group comprises patients with refractory ascites and related complications, such as hepatorenal syndrome and hepatic hydrothorax. It has been demonstrated that TIPS improves these complications. Five randomized studies comparing TIPS with paracentesis and one study comparing TIPS with the peritoneo-venous shunt showed good response of ascites but controversial results on survival. In addition, TIPS has been successfully applied to patients with Budd-Chiari syndrome, portal vein thrombosis, before liver transplantation, and for the treatment of ectopic variceal bleeding.

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.

Results of a Retrospective Multicenter Trial of the Viatorr Expanded Polytetrafluoroethylene– covered Stent-Graft for Transjugular Intrahepatic Portosystemic Shunt Creation

PURPOSE

To report the results of a multicenter experience with the Viatorr expanded polytetrafluoroethylene-covered stent-graft for transjugular intrahepatic portosystemic shunt (TIPS) creation in which patency and clinical outcome were evaluated.

MATERIALS AND METHODS

One hundred consecutive patients with portal hypertension, with a mean age of 52 years (range, 22-86 years), underwent implantation of the Viatorr TIPS stent-graft at one of three hospital centers. The indications for TIPS creation were variceal bleeding (n = 81) and refractory ascites (n = 19). Twenty patients had Child-Pugh class A disease, 46 had class B disease, and 34 had class C disease. Eighty-seven patients underwent de novo TIPS placements, with 13 treated for recurrent TIPS stenosis. Sixty-two patients were available for follow-up portal venography and portosystemic pressure gradient (PSG) measurement commencing 6 months after Viatorr stent-graft placement.

RESULTS

The technical success rate was 100%. TIPS creation resulted in an immediate decrease in mean PSG (+/-SD) from 21 mm Hg +/- 6 to 7 mm Hg +/- 3. Acute repeat intervention (within 30 days) was required for portal vein thrombosis (n = 1), continued bleeding (n = 3), and encephalopathy (n = 1). The all-cause 30-day mortality rate was 12%. Two patients developed acute severe refractory encephalopathy, which led to death in one case. New or worsening encephalopathy was identified in 14% of patients. The incidence of recurrent bleeding was 8%. The cumulative survival rate at 1 year was 65%. Sixty-two patients available for venographic follow-up had a mean PSG of 9 mm Hg +/- 5 at a mean interval of 343 days (range, 56-967 days). There were four stent-graft occlusions (6%) and seven hemodynamically significant stenoses (11%), four within the stent-graft and three in the non-stent-implanted hepatic vein. The primary patency rate at 1 year by Kaplan-Meier analysis was 84%.

CONCLUSIONS

This retrospective multicenter experience with the Viatorr stent-graft confirms the preliminary findings of other investigators of good technical results and improved patency compared with bare stents. Early mortality and symptomatic recurrence rates are low by historical standards. The theoretical increase in TIPS-related encephalopathy was not demonstrated. Longer-term follow-up will be required to determine whether the additional cost of the Viatorr stent-graft will be offset by reduced surveillance and repeat intervention.

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.

Direct intrahepatic portacaval shunt: An experimental study

AIM: To determine the feasibility of creating direct intrahepatic portacaval shunt (DIPS) in swine with puncture under sonographic guidance.

METHODS: DIPS was created in 10 domestic swine under sonographic guidance. Liver function, blood ammonia level and portosystemic gradient (PSG) were compared before and after the procedure. Patency of shunt was followed by portography every 7 d after DIPS.

RESULTS: DIPS was successfully established in all 10 swine without any complications. One day after procedure the alanine aminotransferase (ALT), aspartate aminotransferase (AST), and blood ammonia level (BAL) of swine rose from 5.40 ± 0.69, 16.00 ± 0.79 and 35.66 ± 4.10 to 34.20 ± 3.46, 59.70 ± 2.22 and 66.94 ± 3.44 respectively (P < 0.05). The PSG decreased from 0.59 ± 0.20 kPa to 0.24 ± 0.11 kPa after DIPS (P < 0.05). The shunt of 10 swine was kept patent from 7-28 d (median patency time was 14 d).

CONCLUSION: This initial experience demonstrated that creating intrahepatic portacaval shunt from retrohepatic segment of IVC to portal vein with puncture under sonographic guidance in swine is safe and feasible. Further studies are necessary to perform DIPS in cirrhosis patients.

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

PURPOSE

To determine if cardiac pulsations are visible and quantifiable on spectral waveforms during Doppler ultrasonographic (US) evaluation of transjugular intrahepatic portosystemic shunts (TIPS), and if so, whether their magnitude declines with shunt dysfunction.

MATERIALS AND METHODS

Baseline and pre-revision US images obtained in 15 patients with venographically confirmed TIPS malfunction were retrospectively examined for spectral waveform pulsation. Cardiac pulsatility was quantified by using the venous pulsatility index (VPI), the venous equivalent of resistive index. VPIs were obtained at four locations from the main portal vein to the stent-hepatic venous junction. Baseline and follow-up examination results in 11 patients with functional TIPS acted as controls and were evaluated similarly. Baseline and follow-up mean VPIs at all four locations were compared for both sets of patients by using the Newman-Keuls pairwise multiple sample comparison test. The chi(2) test was used to determine if a VPI threshold that would result in an acceptable sensitivity and specificity for shunt dysfunction existed.

RESULTS

One hundred twenty mean VPIs were obtained in the study group, and 88 mean VPIs were obtained in the control group. Pre-revision VPIs at each location were significantly lower (P <.01) than all baseline values and than the follow-up values in the control group. A VPI less than 0.16 was 94% sensitive and 87% specific for shunt dysfunction.

CONCLUSION

The VPI, a quantitative measure of cardiac pulsation obtained with Doppler US, may be a useful parameter for assessing TIPS function.

Management of suspected hemodialysis graft dysfunction: usefulness of diagnostic US

PURPOSE

To evaluate the role and usefulness of diagnostic ultrasonography (US) in the assessment of hemodialysis access grafts with an intermediate probability of graft malfunction.

MATERIALS AND METHODS

One hundred forty-seven complete US examinations were performed in 91 patients. Average volume of flow, peak systolic velocity, and diameter of residual lumen were recorded. Patients were referred by the nephrology department when clinical findings were suggestive, but not obviously, of graft malfunction. Study results were deemed normal if flow volume exceeded 1,300 mL/min without significant visualized stenosis of 50% of the diameter or greater or if flow approached 1,300 mL/min without peak systolic velocity greater than 400 cm/sec.

RESULTS

Of the 147 examinations, 49 (33%) had normal results, seven (5%) showed thrombosis at examination, and 91 (62%) had evidence of at least one significant visualized stenosis or diffuse notable degree of thrombus. Three patients with normal results required fistulography within 90 days, one for thrombosis. In the 91 studies with abnormal results, 69 patients underwent fistulography; results in 63 showed agreement, and three showed false-positive results. More central venous stenoses were found at fistulography than at US.

CONCLUSION

US is a useful and reliable first step in managing clinically suspected hemodialysis graft stenosis. One-third of the studies showed no significant stenosis and did not require angiographic evaluation. US should be the initial study in patients suspected of having hemodialysis access dysfunction without exceptional evidence of stenosis.

[TIPS - Transjugular intrahepatic portosystemic shunt. A review]

At the present time several therapeutic options are used for the treatment of bleeding esophageal varices in patients with portal hypertension. We will review the main medical publications on transjugular intrahepatic portosystemic shunt (TIPS), a procedure seldom used among us. TIPS works as a portocaval side-to-side shunt and decreases the risk of esophageal bleeding through lowering of the portal system pressure and a decrease of the portal hepatic pressure gradient. TIPS consists in the percutaneous insertion, through the internal jugular vein, of a metallic stent under fluoroscopic control in the hepatic parenchyma creating a true porta caval communication. There are several studies demonstrating the efficacy of TIPS, although only a few of them are randomized and control-matched to allow us to conclude that this procedure is safe, efficient and with a good cost benefit ratio. In this review, we search for the analysis of the TIPS utilization, its techniques, its major indications and complications. TIPS has been used in cases of gastroesophageal bleeding that has failed with pharmacologic or endoscopic treatment in patients Child-Pugh B and C. It can be used also as a bridge for liver transplantation. Others indications for TIPS are uncontrolled ascites, hepatic renal syndrome, and hepatic hydrothorax. The main early complications of TIPS using are related to the insertion site and hepatic encephalopathy and the stent occlusion is the chief late complication.

Value of Doppler sonography in revealing transjugular intrahepatic portosystemic shunt malfunction: a 5-year experience in 216 patients

OBJECTIVE

The purpose of the study was to evaluate the long-term clinical efficacy of Doppler sonography in revealing failure of transjugular intrahepatic portosystemic shunts (TIPS).

SUBJECTS AND METHODS

During a 5-year period, 1192 Doppler examinations were performed in 216 patients with TIPS. No regular follow-up shunt venography was performed. Doppler examinations were retrospectively compared with the results of shunt revisions. Sonograms with negative findings were compared with the patients' clinical status so that the number of false-negative sonographic findings leading to an episode of shunt failure (recurrence of gastrointestinal bleeding or ascites) could be ascertained. Sonographic parameters assessed included diameter, velocity, flow volume, and congestion index of the portal vein; and shunt velocities.

RESULTS

Doppler sonography revealed shunt occlusion in 25 of 26 angiographically proven cases (sensitivity, 96%). The combination of velocity criteria (peak intrashunt velocity > or =250 cm/sec, maximum velocity in the portal third of the shunt < or =50 cm/sec, or maximum portal vein velocity less than or equal to two thirds of the baseline value) revealed shunt stenosis in 103 of 110 cases (sensitivity, 94%). Doppler sonography missed a significant shunt stenosis that led to an episode of gastrointestinal bleeding or ascites recurrence in only seven cases. The congestion index of the portal vein showed significant differences between patent and malfunctioning shunts (p < 0.001).

CONCLUSION

Doppler sonography is an effective primary imaging method for long-term follow-up of patients with TIPS.

Transjugular intrahepatic portosystemic shunts (TIPS): a decade later

Since the introduction of transjugular intrahepatic portosystemic shunt (TIPS) 10 years ago, it has been used increasingly in the management of portal hypertension and its complications. TIPS is now considered the procedure of choice for management of refractory variceal bleeding. Its role in the management of refractory ascites, hepatic hydrothorax, hepatorenal syndrome, and hepatopulmonary syndrome still awaits further prospective studies. The two main complications of TIPS are hepatic encephalopathy and shunt malfunction. Generally, TIPS stenosis or occlusion is a major drawback requiring routine surveillance of TIPS with doppler ultrasound. Venography with balloon dilation of the stent or placement of serial or parallel stents may be required in some cases. Promising modalities of preventing TIPS malfunction (e.g., brachy-therapy, covered stents, or anti-platelet derived growth factor) are currently being investigated.

Improved patency of transjugular intrahepatic portosystemic shunts in humans: creation and revision with PTFE stent-grafts

PURPOSE

To determine whether polytetrafluoroethylene (PTFE) stent-grafts yield longer patency for creation or revision of transjugular intrahepatic portosystemic shunts (TIPS).

MATERIALS AND METHODS

Fourteen PTFE-covered Wallstents were placed in 13 patients with TIPS: seven at shunt creation and seven during revision of TIPS with one to five prior thromboses at 1 day to 1 year after initial TIPS formation. In six cases, prior to stent-graft placement persistent biliary-TIPS fistulas were demonstrated despite repeated shunt revisions with additional metallic stents.

RESULTS

All but one graft-lined TIPS were widely patent at a mean duration of venographic follow-up of 19 months (median, 17 months; range, 5-32 months). The limiting percentage of stenosis within the grafted shunts was 0%-10%. One patient developed stent-graft thrombosis; the prior biliary-TIPS fistula was seen despite the graft. A second, parallel PTFE-lined transcaval shunt was created in this patient; it was widely patent at 11-month follow-up. In two asymptomatic patients, stenoses developed in the short, nongrafted portions of the outflow hepatic veins.

CONCLUSION

PTFE stent-grafts can markedly prolong TIPS patency, potentially reducing the need for shunt follow-up and revision and the risk of recurrent symptoms associated with shunt stenosis or occlusion.