Right hepatic vein stenosis at anastomosis in patients after living donor liver transplantation: optimal Doppler US venous pulsatility index and CT criteria--receiver operating characteristic analysis

Asian Pacific Association for the Study of the Liver clinical practice guidelines on liver transplantation

Liver transplantation is a highly complex and challenging field of clinical practice. Although it was originally developed in western countries, it has been further advanced in Asian countries through the use of living donor liver transplantation. This method of transplantation is the only available option in many countries in the Asia-Pacific region due to the lack of deceased organ donation. As a result of this clinical situation, there is a growing need for guidelines that are specific to the Asia-Pacific region. These guidelines provide comprehensive recommendations for evidence-based management throughout the entire process of liver transplantation, covering both deceased and living donor liver transplantation. In addition, the development of these guidelines has been a collaborative effort between medical professionals from various countries in the region. This has allowed for the inclusion of diverse perspectives and experiences, leading to a more comprehensive and effective set of guidelines.

Diagnostic accuracy of CT and Doppler US for hepatic outflow obstruction after pediatric liver transplantation using left lobe or left lateral section grafts

PURPOSE

The aim of this study was to evaluate diagnostic accuracy and to establish computed tomography (CT) and Doppler ultrasonography (US) criteria for hepatic outflow obstruction after pediatric liver transplantation (LT) using left lobe (LL) or left lateral section (LLS) grafts.

METHODS

Pediatric patients who underwent LT using LL or LLS grafts between January 1999 and December 2021 were retrospectively included. The diagnostic performance of Doppler US and CT parameters for hepatic outflow obstruction was calculated using receiver operating characteristic (ROC) curve analysis. A diagnostic decision tree model combining the imaging parameters was developed.

RESULTS

In total, 288 patients (150 girls; median age at LT, 1.8 years [interquartile range, 0.9 to 3.6 years]) were included. Among the Doppler US parameters, venous pulsatility index (VPI) showed excellent diagnostic performance (area under the ROC curve [AUROC], 0.90; 95% confidence interval [CI], 0.86 to 0.93; Youden cut-off value, 0.40). Among the CT parameters, anastomotic site diameter (AUROC, 0.92; 95% CI, 0.88 to 0.95; Youden cut-off, 4.2 mm) and percentage of anastomotic site stenosis (AUROC, 0.88; 95% CI, 0.84 to 0.92; Youden cut-off, 35%) showed excellent and good diagnostic performance, respectively. A decision tree model combining the VPI, peak systolic velocity, and percentage of anastomotic site stenosis stratified patients according to the risk of hepatic outflow obstruction.

CONCLUSION

VPI, anastomotic site diameter, and percentage of anastomotic site stenosis were reliable imaging parameters for diagnosing hepatic outflow obstruction after pediatric LT using LL or LLS grafts.

Endovascular treatment of symptomatic hepatic venous outflow obstruction post major liver resection

PURPOSE

To evaluate efficacy, safety, and outcomes of endovascular treatment of hepatic vein stenosis post major liver resection.

METHODS

A retrospective data analysis was performed including all interventional treatments of hepatic vein stenosis post major liver resection since 2010. Post procedural course and clinical parameters including amount of ascites accumulation and relevant laboratory values were assessed during the follow-up period. Primary and primary assisted hepatic venous patency time were calculated.

RESULTS

Twelve patients (median age 55.5, IQR 49.75 to 61.5 years) undergoing a total of 16 interventions were included. Interventions were primary stent placement (n = 3), primary balloon angioplasty (n = 8), three re-interventions and two aborted interventions (no significant pressure gradient). Technical success was 100% (16/16). Permanent reduction and / or complete resolution of ascites was achieved in 72% (8/11). Laboratory parameters related to liver function did not show significant improvement after intervention. Median follow-up period was 6 months (IQR: 1.5 to 18 months). The median primary patency time for patients with balloon angioplasty was 11 months (IQR: 1.375 to 22.25 months) and assisted patency time was 13.25 months (IQR: 4.5 to 22.25 months). The median primary patency time for patients with angioplasty and stent placement was 1 months (IQR: 1.0 to 1.5 months) and assisted patency time was 2.0 months (IQR: 1.5 to 2.5months).

CONCLUSION

An endovascular approach for the treatment of hepatic venous stenosis post major liver resection is safe and efficient to reduce and / or resolve refractory ascites. However, liver function parameters seem not to be improved by the procedure. Stent placement can be a reasonable option in patients with significant residual stenotic disease post angioplasty.

Venous outflow reconstruction using a polytetrafluoroethylene (PTFE) graft in right lobe living donor liver transplantation: A single center study

BACKGROUND

Venous outflow reconstruction is very important especially in right lobe living donor liver transplantation without middle hepatic vein. Various interposition (venous or synthetic) grafts have been recommended for reconstruction of anterior sector tributaries.

METHODS

We aimed to describe our surgical technique and analyze anterior sector venous reconstruction using expanded polytetrafluroethylene graft. Retrospective analysis of prospectively collected data for 760 primary right lobe living donor liver transplantations performed at our institute between December 2011 and June 2018. Reconstruction of anterior sector: expanded polytetrafluroethylene (group A, n = 705) and autologous vein (group B, n = 55).

RESULTS

Pretransplant characteristics were comparable among both groups. Group A has significantly lower cold ischemia time (68.7 ± .3.5 minutes vs 127.8 ± 7.2 minutes; P < .001) and anhepatic time (116.3 ± 5.5 minutes vs 190.81 ± 9.35 minutes; P < .001) compared with group B. There was no difference in recovery pattern of liver functions, morbidity, and mortality between the 2 groups. One- and 6-month patency rates of interposition grafts were 97.6% and 84.4% (group A) and 96.4% and 78.1% (group B), respectively.

CONCLUSION

In centers with limited access to homologous or autologous vascular grafts, use of expanded polytetrafluroethylene graft for anterior sector venous outflow reconstruction in right lobe living donor liver transplantation is a viable option with excellent patency and patient outcomes.

Hepatic Venous Outflow Stenosis After Auxiliary Left Hemiliver Transplantation Diagnosed by Ultrasonic Shear Wave Elastography Combined With Doppler Ultrasonography

Hepatic vein stenosis after liver transplantation is a relatively rare complication that could even result in graft loss. However, it is difficult to arrive at a definite diagnosis at the early stage of postoperation, and there are few researches on ultrasonic shear wave elastography in the diagnosis of hepatic vein stenosis. We report the case of an 11-year-old male patient with cirrhosis due to hepatolenticular degeneration who received an auxiliary left hemiliver graft from his uncle. Massive ascites developed in 4 days after the operation. Stenosis was suspected at the site of anastomosis by Doppler ultrasonography when elevating the velocity of the left hepatic vein. Meanwhile, increased stiffness of the graft was revealed by ultrasonic shear wave elastography. The stenosis was confirmed by subsequent digital subtraction angiography. Ascites decreased gradually after the stent implantation. Our case indicates that ultrasonic shear wave elastography combined with Doppler ultrasonography is a promising method for noninvasive diagnosis of hepatic venous outflow stenosis following liver transplantation.

Efficacy and patency of primary stenting for hepatic venous outflow obstruction after living donor liver transplantation

BACKGROUND

Hepatic venous outflow is important for graft survival in living donor liver transplantation (LDLT). If hepatic venous outflow obstruction occurs, hepatic vein stenting is considered to restore the patency.

PURPOSE

To retrospectively evaluate the efficacy and patency of primary hepatic vein stenting for hepatic venous outflow obstruction (HVOO) after LDLT.

MATERIAL AND METHODS

Percutaneous interventions, including hepatic vein stent placement with or without balloon angioplasty, were performed in 21 patients who had undergone LDLT and had HVOO confirmed through hepatic venography or manometry, including the patients who had a structural abnormality. Two stents each were inserted in four patients; therefore, the total number of treated anastomoses was 25. Technical success, patency rates, and pressure gradients between hepatic veins and the right atrium were evaluated in 19 patients each.

RESULTS

Technical success was achieved in 25 of 26 vessels (96%). The mean interval between operation and stenting was 43 days. After the procedure, the follow-up period was a mean 530 days. The mean pressure gradient decreased from 8.5 mmHg to 2.1 mmHg after treatment (P < 0.01). The patency rates of the 25 vessels were 80% at 1, 2, and 3 years after stent placement. However, middle hepatic vein stenting revealed a low patency rate (all were 36%). Three of seven stents (43%) in the middle hepatic vein occluded during follow-up.

CONCLUSION

Percutaneous primary hepatic vein stent replacement is an effective treatment for HVOO after LDLT.

Vascular complications after adult living donor liver transplantation: Evaluation with ultrasonography

Living donor liver transplantation (LDLT) has been widely used to treat end-stage liver disease with improvement in surgical technology and the application of new immunosuppressants. Vascular complications after liver transplantation remain a major threat to the survival of recipients. LDLT recipients are more likely to develop vascular complications because of their complex vascular reconstruction and the slender vessels. Early diagnosis and treatment are critical for the survival of graft and recipients. As a non-invasive, cost-effective and non-radioactive method with bedside availability, conventional gray-scale and Doppler ultrasonography play important roles in identifying vascular complications in the early postoperative period and during the follow-up. Recently, with the detailed vascular tracing and perfusion visualization, contrast-enhanced ultrasound (CEUS) has significantly improved the diagnosis of postoperative vascular complications. This review focuses on the role of conventional gray-scale ultrasound, Doppler ultrasound and CEUS for early diagnosis of vascular complications after adult LDLT.

Application of contrast-enhanced ultrasound after liver transplantation: Current status and perspectives

Liver transplantation is an effective treatment for patients with end-stage liver disease. Accurate imaging evaluation of the transplanted patient is critical for ensuring that the limited donor liver is functioning appropriately. Ultrasound contrast agents (UCAs), in combination with contrast-specific imaging techniques, are increasingly accepted in clinical use for the assessment of the hepatic vasculature, bile ducts and liver parenchyma in pre-, intra- and post-transplant patients. We describe UCAs, their technical requirements, the recommended clinical indications, image interpretation and the limitations for contrast-enhanced ultrasound applications in liver transplantation.

Usefulness of B-mode and doppler sonography for the diagnosis of severe acute viral hepatitis A

BACKGROUND

To investigate B-mode and Doppler ultrasonography (US) features correlating with laboratory findings for the diagnosis of severe acute hepatitis (SAH) in patients with hepatitis A virus infection.

METHODS

Thirty-nine consecutive serologically proven patients were enrolled. Decreased parenchymal echotexture, periportal tracking, gallbladder wall change, and splenomegaly were assessed on B-mode images. Blood flow velocities were measured in the main portal (V(PORTAL)) and in the hepatic veins, and the hepatic venous pulsatility index was calculated. SAH was defined as high model for end-stage liver disease (MELD) score ≥ 15 with or without coagulopathy. The relationship between US features and laboratory findings was assessed, and SAH diagnosis was evaluated.

RESULTS

Serum alanine transaminase and prothrombin time were significantly different depending on the presence of gallbladder wall change and splenomegaly (p < 0.05). V(PORTAL) was inversely correlated with MELD score (r = -0.485) and several laboratory markers. The hepatic venous waveform and hepatic venous pulsatility index were significantly correlated with MELD score. For the diagnosis of SAH, the area under the receiver operating characteristic curve of V(PORTAL) was 0.798. It reached 0.869 in the patients with typical GB change.

CONCLUSIONS

Both B-mode and Doppler US correlated well with several laboratory variables and may be helpful to diagnose SAH in patients with hepatitis A virus infection.

Sequential preoperative hepatic vein embolization after portal vein embolization for extended left hepatectomy in colorectal liver metastases

Background

The role of portal vein embolization to increase future liver remnant (FLR) is well-established in the treatment of colorectal liver metastases. However, the role of hepatic vein embolization is unclear.

Case report

A patient with colorectal liver metastases received neoadjuvant chemotherapy prior to attempted resection. At the time of resection his tumor appeared to invade the left and middle hepatic vein, requiring an extended left hepatectomy including segments five and eight. Post-operatively, he underwent sequential left portal vein embolization followed by left hepatic vein embolization and finally, middle hepatic vein embolization. Hepatic vein embolization was performed to increase the FLR as well as to allow collateral drainage of the FLR to develop. A left trisectionectomy was then performed and no evidence of postoperative liver congestion or morbidity was found.

Conclusion

Sequential portal vein embolization and hepatic vein embolization for extended left hepatectomy may be considered to increase FLR and may prevent right hepatic congestion after sacrificing the middle vein.

Contrast-enhanced sonography for screening of vascular complication in recipients following living donor liver transplantation

The purpose of this article is to discuss the role of CEUS for screening of vascular complication in recipients admitted to ICU following LDLT, effect of microbubble contrast agent on Doppler phenomenon, CEUS technique, and illustrate CEUS findings in recipients with complication following LDLT. CEUS can enhance the role of US in the diagnosis of postoperative vascular complication in recipients following living donor liver transplantation at the bedside.

How to avoid graft thrombosis requiring graftectomy: immediate posttransplant CT angiography in pancreas transplantation

BACKGROUND

Graft thrombosis immediately after surgery remains a problem for successful pancreas transplantation. The present study evaluated the efficacy of computed tomography (CT) angiography for monitoring of graft patency in the immediate postoperative period.

METHODS

The study involved 119 patients who underwent pancreas transplantation between July 1992 and December 2009 in a single center. The anticoagulation strategy was heparin during and after transplantation and then oral warfarin for 1 to 6 months. Graft thrombosis was monitored using color Doppler ultrasonography until July 2005 (group A) and, thereafter, using CT angiography (group B). We retrospectively analyzed the efficacy of diagnosis of graft thrombosis in two groups. Graft survival was assessed using Kaplan-Meier analysis.

RESULTS

Group A comprised 51 patients, and group B comprised 68 patients. Total vascular thrombosis was diagnosed in three (5.9%) group A and one (1.4%) group B patients, and partial venous thrombosis was diagnosed in 1 (2.0%) group A and 19 (31.6%) group B patients. Eighteen of the 19 grafts with partial thrombosis in group B were successfully treated using heparin-based anticoagulant therapy. There were no CT contrast media-related complications in group B. In group B, graft survival rates were the same for grafts with partial thrombosis and grafts without thrombosis.

CONCLUSIONS

CT angiography was safe and effective for evaluating graft patency after pancreas transplantation. Partial vascular thrombosis in the immediate posttransplantation period showed no effect on graft survival under intensive anticoagulation and monitoring by CT angiography.

Obstruction at middle hepatic venous tributaries in modified right lobe grafts after living-donor liver Transplantation: diagnosis with contrast-enhanced US

PURPOSE

To investigate the ability of contrast material-enhanced ultrasonography (US) to help diagnose obstruction of middle hepatic venous (MHV) tributaries soon after living-donor liver transplantation with modified right lobe grafts.

MATERIALS AND METHODS

The institutional review board approved the study and waived requirement for informed consent. Sixty-five consecutive patients (48 men, 17 women; mean age, 52.8 years; range, 33-69 years) who underwent living-donor liver transplantation with modified right lobe grafts between February and May 2009 were included. All patients underwent contrast-enhanced US and Doppler US on postoperative day 1 and underwent computed tomography (CT) within 7 days after US. At contrast-enhanced US, parenchymal enhancement patterns in the territory of each MHV tributary during arterial and portal venous phases were evaluated. With use of most frequent enhancement patterns in patients with obstruction at MHV tributaries as a criterion, diagnostic performance of contrast-enhanced US was compared with that of Doppler US for diagnosis of obstruction at MHV tributaries; CT was the reference standard. Generalized estimating equations were used to adjust for data clustering.

RESULTS

Of 148 MHV tributaries in 65 patients, 36 (24.3%) in 31 patients were diagnosed as obstructed at CT. With arterial high echogenicity or portal low echogenicity used as a criterion for hepatic venous obstruction, contrast-enhanced US had sensitivity, specificity, and accuracy of 91% (33 of 36), 97% (109 of 112), and 95% (142 of 148), respectively, whereas Doppler US had values of 83% (30 of 36), 86% (97 of 112), and 85% (127 of 148), respectively. Contrast-enhanced US was significantly more specific and accurate than Doppler US for diagnosis of obstruction at MHV tributaries (P=.024 and .01, respectively). Arterial high echogenicity was noted only in the hepatic venous obstruction group.

CONCLUSION

Contrast-enhanced US can help accurately assess hepatic venous obstruction at MHV tributaries after living-donor liver transplantation with a modified right lobe graft. Contrast-enhanced US was significantly more specific than Doppler US, with arterial hyperenhancement in the affected area being specific to hepatic venous obstruction.

Hemodynamics-compliant reconstruction of the right hepatic vein for adult living donor liver transplantation with a right liver graft

Secure reconstruction of the right hepatic vein (RHV) is essential for the successful implantation of a right liver graft during living donor liver transplantation (LDLT). To develop reliable surgical techniques for RHV reconstruction, we performed 3 concurrent studies: a simulation study using a fluid dynamics experimental model and a computational simulation model; an observational study analyzing the hemodynamic changes during radiological interventions for RHV stenosis; and a prospective clinical study establishing hemodynamics-compliant surgical techniques. The simplified fluid dynamics experimental model revealed that actually measured outflow volumes were very similar to theoretical values derived from a fluid dynamics formula. The computational simulation model showed that outflow decreases were nearly linearly correlated with the degree of stenosis when it exceeded 50%. The clinical observational study revealed that mild (≤50%), moderate (50%-75%), and severe RHV stenoses (≥75%) had mean pressure gradients of 2.5 ± 1.0, 6.6 ± 2.3, and 9.6 ± 2.8 mm Hg, respectively. The prospective clinical study was performed for patients who underwent RHV reconstruction with RHV angle blunting and inferior vena cava enlargement (n = 274); a historical control group of patients who underwent reconstruction by other methods (n = 225) was also used. RHV stenting within 2 weeks and 1 year was necessary for 1 patient (0.4%) and 5 patients (1.8%) in the study group, respectively, and for 9 patients (4.0%) and 21 patients (9.1%) in the control group, respectively (P < 0.01). The mean cephalocaudal length of patulous RHV anastomoses was greater in the study group versus the control group (P < 0.001). In conclusion, our modified RHV reconstruction technique significantly reduces the risk of RHV stenosis. We thus suggest the routine or selective use of this technique as a part of graft standardization for LDLT using a right liver graft.

Acute outflow obstruction of hepatic veins in rabbits: quantitative analysis of hepatic perfusion with contrast-enhanced sonography

OBJECTIVES

To compare time-enhancement curve parameters of contrast-enhanced sonography in acute partial hepatic venous outflow obstruction with those of a baseline study.

METHODS

Contrast-enhanced sonography was performed in 11 rabbits with bolus administration of a sulfur hexafluoride contrast agent (0.1 mL/kg). After baseline scanning for 3 minutes, a 5.3F balloon catheter was placed into the left hepatic vein. Obstruction was artificially induced by 0.4-mL balloon inflation, and sonography was repeatedly performed thereafter. On images stored with 1-second intervals, 2 × 2-mm regions of interest were placed, and mean luminosity was measured. Time-enhancement curves were plotted, and contrast arrival times, peak enhancement values, peak enhancement times, 50% wash-out times, and 3-minute wash-out rates were obtained. Paired t tests were performed to evaluate the significance of differences in the parameters between baseline and obstruction.

RESULTS

On baseline sonography, the median contrast arrival time, peak enhancement value, peak enhancement time, 50% wash-out time, and 3-minute wash-out rate were 6 (range, 4-8; mean ± SD, 5.9 ± 1.2) seconds, 188.5 (104.7-209.5; 178.4 ± 33.1) arbitrary units, 19 (14-27; 19.8 ± 4.1) seconds, 75 (60-101; 78.2 ± 13.9) seconds, and 89.7% (81.3%-95.1%; 88.4% ± 4.9%), respectively. With obstruction, those values were 7 (5-12; 6.9 ± 2.3) seconds, 202.8 (98.2-215.1; 186.0 ± 39.3) arbitrary units, 31 (17-59; 32 ± 11.6) seconds, 101 (47-136; 96.2 ± 23.6) seconds, and 79.2% (66.2%-88.8%; 79.1% ± 7.6%). Compared with baseline, the peak enhancement time was significantly delayed from 19 to 31 seconds (P = .0027), 50% wash-out time significantly delayed from 75 to 101 seconds (P = .0209), and 3-minute wash-out rate significantly decreased from 89.7% to 79.2% (P < .0001) with obstruction, but there were no significant differences in contrast arrival times and peak enhancement values (P = .0756 and .2179).

CONCLUSIONS

Contrast-enhanced sonography can provide quantitative assessment of microbubble congestion in partial hepatic venous outflow obstruction. The peak enhancement time and 50% wash-out time are delayed and 3-minute wash-out rate is decreased in rabbits with artificially induced obstruction compared with a baseline study.