Use of intraoperative Doppler ultrasound to diagnose hepatic venous obstruction in a right lobe living donor liver transplant

European Society of Pediatric Radiology survey of perioperative imaging in pediatric liver transplantation: (2) intraoperative imaging

BACKGROUND

Liver transplantation is the state-of-the-art curative treatment for end-stage liver disease. Imaging is a key element in the detection of intraoperative and postoperative complications. So far, only limited data regarding the best radiological approach to monitor children during liver transplantation is available.

OBJECTIVE

To harmonize the imaging of pediatric liver transplantation, the European Society of Pediatric Radiology Abdominal Taskforce initiated a survey addressing the current status of imaging including the pre-, intra- and postoperative phase. This paper reports the responses related to intraoperative imaging.

MATERIALS AND METHODS

An online survey, initiated in 2021, asked European centers performing pediatric liver transplantation 48 questions about their imaging approach. In total, 26 centers were contacted, and 22 institutions from 11 countries returned the survey.

RESULTS

Intraoperative ultrasound (US) is used by all sites to assess the quality of the vascular anastomosis in order to ensure optimal perfusion of the liver transplant. Vessel depiction is commonly achieved using color Doppler (95.3%). Additional US-based techniques are employed by fewer centers (power angio mode, 28.6%; B-flow, 19%; contrast-enhanced US, 14.3%). Most centers prefer a collaborative approach, with surgeons responsible for probe handling, while radiologists operate the US machine (47.6%). Less commonly, the intraoperative US is performed by the surgeon alone (28.6%) or by the radiologist alone (23.8%). Timing of US, imaging frequency, and documentation practices vary among centers.

CONCLUSION

Intraoperative US is consistently utilized across all sites during pediatric liver transplantation. However, considerable variations were observed in terms of the US setup, technique preferences, timing of controls, and documentation practices. These differences provide valuable insights for future optimization and harmonization studies.

Current approach to intraoperative monitoring in liver transplantation

PURPOSE OF REVIEW

Although liver transplantation has become a standardized treatment and the only established definite therapy for end-stage liver disease it remains a unique clinical procedure. Increased understanding of the specific pathophysiological changes in end-stage liver disease and the transplantation procedure have led to the adaptation of concepts including overall monitoring of the patient and assessment of specific organ function.

RECENT FINDINGS

Major emphasis is placed on adequate monitoring during perioperative care of liver transplantation patients in order to ensure optimal hemodynamic and respiratory performance. The immediate assessment of metabolism and graft function will also serve to guide therapy according to the individual patient's needs.

SUMMARY

The evolution of monitoring during standardized liver transplantation, as well as currently recommended novel devices and concepts, are described and discussed.

Value of CT and Doppler Sonography in the Evaluation of Hepatic Vein Stenosis After Dual-Graft Living Donor Liver Transplantation

OBJECTIVE

The purpose of this study was to evaluate the imaging findings and role of CT and Doppler sonography in the diagnosis of hepatic vein (HV) stenosis after dual-graft living donor liver transplantation (LDLT).

MATERIALS AND METHODS

Using hepatic venography as the reference standard, 73 grafts with venographic evaluation in 43 dual-graft LDLT recipients were classified into either a stenosis (n = 39) or a nonstenosis (n = 34) group. CT scans were evaluated for relative attenuation, enhancement pattern, and HV abnormality for each graft. Doppler sonography evaluation of the flow pattern of HVs for each graft was performed. CT and Doppler sonography findings were compared in the stenosis and nonstenosis groups using the independent sample Student's t test and Fisher's exact test. Multifactorial logistic regression analysis was performed to determine the best predictors of the diagnosis of HV stenosis.

RESULTS

Heterogeneous enhancement (p = 0.046), abnormal HV on CT (p = 0.025), and HV wave pattern on Doppler sonography (p = 0.005) were significant findings. The accuracy for the diagnosis of HV stenosis was 60.0% for heterogeneous enhancement, 61.5% for abnormal HV, and 66.2% for a monophasic flow pattern. Heterogeneous enhancement and HV wave pattern were significant independent findings on multifactorial logistic regression analysis. The overall accuracy of the logistic model in the diagnosis of HV stenosis was 71.7%.

CONCLUSION

Although CT and Doppler sonography can be helpful in diagnosing HV stenosis, given the low accuracy of individual imaging findings, the diagnosis of HV stenosis should be made cautiously, with both CT and Doppler sonography regarded as complementary examinations.

Correction of Left Hepatic Vein Redundancy in Paediatric Liver Transplantation

Redundancy of hepatic vein in the venous outflow reconstruction of partial graft in paediatric liver transplantation may occur when the graft hepatic vein is longer than anticipated. We describe two cases with outflow obstruction due to hepatic vein redundancy. The correction of the redundancy was made by pulling the graft caudally and to the left or right side of the abdominal cavity as determined by Doppler ultrasonography.

Hepatic vein reconstruction in ex situ split-liver transplantation

BACKGROUND

Anatomy of the left hepatic vein (LHV) was studied in a series of 53 consecutive cadaveric liver grafts that were divided for transplantation.

METHODS

All divisions were performed ex situ and provided a left split graft with only the LHV as the hepatic outflow. The anatomy was categorized into three types: (A) single LHV trunk, (B) two veins closely merging toward the median hepatic vein, or (C) a double outflow.

RESULTS

Direct implantation of the graft was performed in type A and was possible in type B after simple plasty of the ostia to create a single orifice. In type C, a venous jump graft could be interposed at bench work to allow direct anastomosis into the recipient. There were no related complications, except one type A case with late outflow obstruction.

CONCLUSION

Liver division can be performed safely in liver grafts with variant LHV anatomy, if appropriate techniques for reconstruction are used. Also ex situ liver division has the advantage of allowing a detailed anatomic evaluation before dividing LHV: reconstruction can be performed ex situ, allowing a single-step direct anastomosis in the recipient, thus shortening suturing time.

Living donor liver transplantation: summary of a conference at The National Institutes of Health

Living donor liver transplantation for adults was developed only recently in an attempt to increase the pool of donor organs; to reduce morbidity and mortality; and to improve the long-term survival of patients in need of liver transplant. Within a few brief years, this procedure has gained widespread support by both the public and transplant community. The procedure will soon be performed by nearly 80% of all liver transplant programs in the United States. Unfortunately, the long-term risks of the procedure to the recipient and especially the donor remain undefined. In response to the rapid growth and enthusiasm for this procedure, the National Institutes of Health sponsored a workshop, the goals of which were to review the scientific, medical, and nonmedical issues associated with living donor liver transplantation, and to define questions for future basic and clinical investigations which could improve the success and applicability of this procedure.