Comparison of three caval reconstruction techniques in orthotopic liver transplantation: A retrospective review

Deceased Donor Liver Transplantation: Techniques and Surgical Anatomy

Deceased liver donor transplantation is increasing in prevalence resulting in larger volumes of posttransplant imaging studies. Radiologists should familiarize themselves with the spectrum of normal posttransplant anatomy. The key findings can be categorized into 4 systems reconstructed during surgery: hepatic venous, portal venous, hepatic arterial, and biliary ductal systems. Here we discuss the imaging findings seen with the most common surgical techniques, those that can be misidentified as complications, and some less common variations resulting from different surgical techniques.

Comparison of the modified piggyback with standard piggyback and conventional orthotopic liver transplantation techniques: a network meta-analysis

BACKGROUND

In conventional orthotopic liver transplantation (OLT), the recipient's retrohepatic inferior vena cava (IVC) is completely clamped and replaced with the donor IVC. The piggyback technique has been used to preserve venous return, either via an end-to-side or standard piggyback (SPB), or via a side-to-side or modified piggyback (MPB) anastomosis, using a venous cuff from the recipient hepatic veins with partially clamping and preserves the recipient's inferior vena cava. However, whether these piggyback techniques improve the efficacy of OLT is unclear. To address the low quality of the available evidence, we performed a meta-analysis to compare the efficacy of conventional, MPB, and SPB techniques.

METHODS

Literature was searched in Medline and Web of Science databases for relevant articles published until 2021 without any time restriction. A Bayesian network meta-analysis was performed to compare the intra- and postoperative outcomes of conventional OLT, MPB, and SPB techniques.

RESULTS

Forty studies were included, comprising 10,238 patients. MPB and SPB had significantly shorter operation times and fewer transfusions of red blood cell and fresh frozen plasma than conventional techniques. However, there were no differences between MPB and SPB in operation time and blood product transfusion. There were also no differences in primary non-function, retransplantation, portal vein thrombosis, acute kidney injury, renal dysfunction, venous outflow complications, length of hospital and intensive care unit stay, 90-day mortality rate, and graft survival between the three techniques.

CONCLUSION

MBP and SBP techniques reduce the operation time and need for blood transfusion compared with conventional OLT, but postoperative outcomes are similar. This indicates that all techniques can be implemented based on the experience and policy of the transplant center.

Portal Vein Recanalization-Transjugular Intrahepatic Portosystemic Shunt (PVR-TIPS) Facilitates Liver Transplantation in Cirrhotic Patients with Occlusive Portal Vein Thrombosis

Portal vein thrombosis (PVT) is a heterogeneous condition with multiple possible etiologies and to varying degrees has historically limited candidacy for liver transplant (LT) in the cirrhotic patient population due to resultant difficulties in constructing a robust portal vein anastomosis. While intraoperative approaches to managing PVT are well-described, methods which approximate normal portal physiology are not always feasible depending on the extent of PVT, and other nonphysiologic techniques are linked with substantial morbidity and poor long-term outcomes. Portal vein recanalization-transjugular intrahepatic portosystemic shunt (PVR-TIPS) creation is an efficacious method of restoring physiologic portal flow in cirrhotic patients prior to LT allowing for end-to-end PV anastomosis, and is the product of decades-long institutional expertise in TIPS/LT and the support of a multidisciplinary liver tumor board. To follow is a review of the pertinent pathophysiology of PVT in cirrhosis, the rationale leading to the development and subsequent evolution of the PVR-TIPS procedure, technical lessons learned, and a summary of outcomes to date.

Transjugular Intrahepatic Portosystemic Shunt in Liver Transplant Recipients: Outcomes in Six Adult Patients

OBJECTIVES

Transjugular intrahepatic portosystemic shunt (TIPS) is regularly used in treatment of clinically significant portal hypertension. Liver transplant recipients are, however, rarely indicated for the procedure. The study retrospectively examines the results of TIPS placement in 6 patients after OLT.

METHODS

4 males and 2 females (aged 36 to 62 years), treated with TIPS between 2007 a 2018, were included in the study. 5 patients had previously undergone liver transplantation for liver graft cirrhosis, 1 patient for Budd-Chiari syndrome. The piggyback caval reconstruction technique was selected in 4/6 cases. PH developed after OLT due to the recurrence of underlying liver condition and sinusoidal obstruction syndrome in half of the cases, respectively. Indications for TIPS were refractory ascites in 4 cases and variceal bleeding in 2 cases.

RESULTS

Standard TIPS technique was used and technical success was achieved in all cases with a procedure-related complication in 1 patient. One patient died shortly after TIPS placement. The remaining patients all reported regression of clinically significant PH. Late complications appeared in 2 patients. Liver retransplantation after TIPS creation was performed in 1 case. Median TIPS patency was 55 months. 2/6 patient continue to thrive with a patent shunt.

CONCLUSIONS

Transjugular intrahepatic portosystemic shunt in OLT recipients is technically feasible. Favorable clinical outcomes were reported particularly in patients treated for sinusoidal obstruction syndrome who were indicated to TIPS for refractory ascites.

CAQ Corner: Surgical evaluation for liver transplantation

The evaluation of a liver transplantation candidate is a complex and detailed process that in many cases must be done in an expedited manner because of the critically ill status of some patients with end-stage liver disease. It involves great effort from and the collaboration of multiple disciplines, and during the evaluation several studies and interventions are performed to assess and potentially prepare a patient for liver transplant. Here we review the liver transplantation evaluation from a surgical perspective.

Which cava anastomotic techniques are optimal regarding immediate and short-term outcomes after liver transplantation: A systematic review of the literature and expert panel recommendations

BACKGROUND

It has long been debated whether cava anastomosis should be performed with the piggyback technique or cava replacement, with or without veno-venous bypass (VVB), with or without temporary portocaval shunt (PCS) in the setting of liver transplantation.

OBJECTIVES

To identify whether different cava anastomotic techniques and other maneuvers benefit the recipient regarding short-term outcomes and to provide international expert panel recommendations.

DATA SOURCES

Ovid MEDLINE, Embase, Scopus, Google Scholar, and Cochrane Central.

METHODS

A systematic review following PRISMA guidelines and recommendations using the GRADE approach derived from an international expert panel (CRD42021240979).

RESULTS

Of 3205 records screened, 307 publications underwent full-text assessment for eligibility and 47 were included in qualitative synthesis. Four studies were randomized control trials. Eighteen studies were comparative. The remaining 25 were single-center retrospective noncomparative studies.

CONCLUSION

Based on existing data and expert opinion, the panel cannot recommend one cava reconstruction technique over another, rather the surgical approach should be based on surgeon preference and center dependent, with special consideration toward patient circumstances (Quality of evidence: Low | Grade of Recommendation: Strong). The panel recommends against routine use of vevo-venous bypass (Quality of evidence: Very Low | Grade of Recommendation: Strong) and against the routine use of temporary porto-caval shunt (Quality of evidence: Very Low | Grade of Recommendation: Strong).

Comparison of Three Inferior Vena Cava Reconstruction Techniques in Adult Orthotopic Liver Transplantation: Result From King Chulalongkorn Memorial Hospital, Thailand

BACKGROUND

In orthotopic liver transplantation (OLT), 3 caval reconstruction techniques are being performed worldwide. These are conventional, piggyback technique, and side-to-side cavocaval anastomosis (CCA). Each has its own advantages and drawbacks. Herein we report the result from our hospital comparing the 3 techniques.

METHODS

We retrospectively reviewed the detail of OLT performed from January 2008 to March 2020. Data being collected included type of caval reconstruction, blood loss, operative time, ischemic time, length of stay in the intensive care unit (ICU) and total hospital stay, and several postoperative complications.

RESULTS

In the given period, 11 conventional, 90 piggyback, and 113 CCA caval reconstruction were done. There were no statistically significant differences in blood loss, operative time, cold ischemic time, and length of ICU and hospital stay. The CCA group had the lowest warm ischemic time (40 minutes) followed by the piggyback technique (43 minutes) and the conventional technique (47 minutes; P < .001). Regarding postoperative complications, there were no statistically significant differences in rate of primary nonfunction, early allograft dysfunction, hepatic artery/portal vein/biliary complication, or rate of acute kidney injury. The hepatic venous outflow complication rate was indifferent between 3 groups.

CONCLUSIONS

The present study showed no difference in outflow obstruction rate among the 3 techniques. The choice for reconstruction should rely on the preference of each institute and the suitability of each patient. The CCA technique may provide the lowest warm ischemic time.

Outcomes in Adult Liver Transplant Recipients Using Pediatric Deceased Donor Liver Grafts

Background.

The use of pediatric grafts for liver transplantation (LT) into adult recipients is rare, and reported outcomes are conflicting. The aim of this study is to evaluate the outcomes in adult recipients following LT with grafts from deceased pediatric donors.

Methods.

A retrospective study identifying adult LT between 2010 and 2020 using pediatric deceased donor liver grafts was conducted. Adults undergoing LT with deceased donor pediatric grafts (age ≤ 12) were identified and matched 1:2 with adults receiving adult grafts (age ≥ 18) based on recipient age (±10 y), model for end-stage liver disease (MELD) score at transplant (±5 points) and etiology of liver disease. To assess real liver size differences between the pediatric-donor and adult-donor groups, patients receiving a graft from a donor between 13 and 17 y were excluded from the main analysis and studied independently. Outcomes between the groups were compared. Complication rates were identified and graded using Clavien–Dindo classification. Graft and patient survival were assessed by Kaplan–Meier curves.

Results.

Twelve adult LT recipients with whole liver grafts from deceased pediatric donors were matched with 24 adult recipients of adult donors. Recipient age and MELD score were similar between groups. Recipients of pediatric grafts were more likely to be female (66.7% versus 16.7%, P = 0.007) and leaner (body mass index = 24.4 versus 29.9, P = 0.013). Alcohol-related cirrhosis was the most prevalent liver disease etiology in both groups (P = 0.96). There was no significant difference in length of stay, readmissions, early complications, or major complications between groups. Vascular and biliary complication rates were similar. Actuarial graft and patient survival at 1, 3, and 5 y were 100/100/100 versus 96/96/96 (P = 0.48).

Conclusions.

Excellent patient and graft survival is achievable with LT using young pediatric deceased donor grafts in smaller adult recipients. Outcomes are comparable with recipients of age and MELD-matched adult donors. Careful donor MELD-score recipient matching and close monitoring for potential biliary and vascular complications are crucial to achieve acceptable outcomes.

Contrast-enhanced ultrasound of transplant organs - liver and kidney - in children

Ultrasound (US) is the first-line imaging tool for evaluating liver and kidney transplants during and after the surgical procedures. In most patients after organ transplantation, gray-scale US coupled with color/power and spectral Doppler techniques is used to evaluate the transplant organs, assess the patency of vascular structures, and identify potential complications. In technically difficult or inconclusive cases, however, contrast-enhanced ultrasound (CEUS) can provide prompt and accurate diagnostic information that is essential for management decisions. CEUS is indicated to evaluate for vascular complications including vascular stenosis or thrombosis, active bleeding, pseudoaneurysms and arteriovenous fistulas. Parenchymal indications for CEUS include evaluation for perfusion defects and focal inflammatory and non-inflammatory lesions. When transplant rejection is suspected, CEUS can assist with prompt intervention by excluding potential underlying causes for organ dysfunction. Intracavitary CEUS applications can evaluate the biliary tract of a liver transplant (e.g., for biliary strictures, bile leak or intraductal stones) or the urinary tract of a renal transplant (e.g., for urinary obstruction, urine leak or vesicoureteral reflux) as well as the position and patency of hepatic, biliary and renal drains and catheters. The aim of this review is to present current experience regarding the use of CEUS to evaluate liver and renal transplants, focusing on the examination technique and interpretation of the main imaging findings, predominantly those related to vascular complications.

An Alternative Surgical Technique of Native Hepatectomy in Liver Transplantation

Background

Orthotopic liver transplantation has become the procedure of choice for end-stage liver disease. There are 3 commonly used methods of vena cava anastomosis. Here, we report a new technique for native hepatectomy.

Material/Methods

The data of 12 patients who underwent orthotopic liver transplantation using a new surgical technique were retrospectively collected for analysis. The new separation and reconstruction surgical technique mainly involved the second portal isolation and hepatectomy that followed. We performed recipient liver resection without the occlusion of the inferior vena cava, which was then followed by classic, piggyback, modified piggyback, or side-to-side orthotopic liver transplantation. The graft function index and complications were collected after transplantation.

Results

The length of the anhepatic phase was 30.92±9.1 min. Alanine transaminase (ALT) levels were 138 to 2027 U/L, with a median of 361.5 U/L. The ALT levels of all patients gradually decreased to normal levels 7 to 10 days after surgery. Only 2 recipients had elevated levels of ALT higher than 1000 U/L. Four of 12 patients did not require red blood cell transfusion during surgery. Four patients appeared to have early allograft dysfunction, while others recovered smoothly.

Conclusions

This new surgical technique may shorten the anhepatic phase and decrease blood loss volume, aiding the success of liver transplant surgery. It can be used for most patients and does not increase the risk of complications or impair prognosis.

Initial piggyback technique facilitates late liver retransplantation - a retrospective monocentric study

Optimal management of inferior vena cava (IVC) is crucial to ensure safety in late liver retransplantation (ReLT). The aim of this study was to evaluate different surgical strategies with regard to IVC in late ReLT. All consecutive late ReLT (≥90 days from the previous transplant) from 2013 to 2018 in a single center was reviewed (n = 66). Of them, 46 (69.7%) were performed without venovenous bypass (VVB) including 29 with caval preservation (CP) and 17 with caval replacement (CR). The remaining 20 cases (30.3%) required the use of VVB. Among ReLT without VVB, CP was associated with a lower number of packed red blood cells (median 4 vs. 7; P = 0.016) and a lower incidence of post-transplant acute kidney injury (6.9% vs. 47.1%; P = 0.003). The feasibility of CP was 95% (14/15) in patients with previous 3-vein piggyback caval anastomosis versus 48.3% (15/31) after other techniques (P = 0.003). Indirect signs of portal hypertension (PHT) before retransplantation were predictive of VVB requirement. Early and long-term outcomes were similar across the three groups (CP without VVB, CR without VVB, and VVB). Preserving the IVC in late ReLT is associated with better postoperative renal function and is facilitated by a previous 3-vein piggyback. Routine CR is not justified in late ReLT.

Machine Learning for the Prediction of Red Blood Cell Transfusion in Patients During or After Liver Transplantation Surgery

Aim: This study aimed to use machine learning algorithms to identify critical preoperative variables and predict the red blood cell (RBC) transfusion during or after liver transplantation surgery. Study Design and Methods: A total of 1,193 patients undergoing liver transplantation in three large tertiary hospitals in China were examined. Twenty-four preoperative variables were collected, including essential population characteristics, diagnosis, symptoms, and laboratory parameters. The cohort was randomly split into a train set (70%) and a validation set (30%). The Recursive Feature Elimination and eXtreme Gradient Boosting algorithms (XGBOOST) were used to select variables and build machine learning prediction models, respectively. Besides, seven other machine learning models and logistic regression were developed. The area under the receiver operating characteristic (AUROC) was used to compare the prediction performance of different models. The SHapley Additive exPlanations package was applied to interpret the XGBOOST model. Data from 31 patients at one of the hospitals were prospectively collected for model validation. Results: In this study, 72.1% of patients in the training set and 73.2% in the validation set underwent RBC transfusion during or after the surgery. Nine vital preoperative variables were finally selected, including the presence of portal hypertension, age, hemoglobin, diagnosis, direct bilirubin, activated partial thromboplastin time, globulin, aspartate aminotransferase, and alanine aminotransferase. The XGBOOST model presented significantly better predictive performance (AUROC: 0.813) than other models and also performed well in the prospective dataset (accuracy: 76.9%). Discussion: A model for predicting RBC transfusion during or after liver transplantation was successfully developed using a machine learning algorithm based on nine preoperative variables, which could guide high-risk patients to take appropriate preventive measures.

Inferior Vena Cava and Venous Outflow Reconstruction in Living Donor Liver Transplantation in Children: A Single-Center Retrospective Study and Literature Review

Background

In this report, we present technical problems and solutions used in the reconstruction of the inferior vena cava and graft venous outflow during living donor liver transplantation (LDLT) in children.

Material/Methods

In 65 grafts out of 379 liver transplantations from living donors, reconstruction of multiple hepatic venous branches and/or IVC was necessary. In 4 cases, cryopreserved deceased donor venous grafts were used for the reconstruction of the IVC and/or HV.

Results

Follow-up ranged from 2 months to 17.8 years (median 7.2 years). In 4 children, liver re-transplantation was required for a reason not related to venous outflow (biliary complications in 3 patients, graft insufficiency caused by small-for-size syndrome). Two patients died: 1 due to tumor recurrence and 1 due to multi-organ failure. Fifty-nine patients are alive with good liver function. One patient (1.5%) after deceased donor venous graft reconstruction showed symptoms of venous outflow obstruction, which was successfully treated with endovascular balloon angioplasty and stent placement. The remaining 59 transplanted patients do not show any signs of venous outflow obstruction.

Conclusions

In most cases, the reconstruction of multiple hepatic veins of living donor allografts can successfully be done with local venoplasty, while using cold-stored vein grafts may be helpful in selected cases of LDLT.

The learning curve for piggyback liver transplantation: identifying factors challenging surgery

BACKGROUND

This study aimed to quantify the learning curve of piggyback liver transplantation and to identify factors that impact the operative time and blood transfusion during the learning curve.

METHODS

A retrospective review was performed on consecutive cases of patients' first piggyback liver transplantations that were performed by a single surgeon. The learning curve for the operative time was evaluated using the cumulative sum method.

RESULTS

There were 181, consecutive, first-time piggyback liver transplantations. The median operative time was 345 minutes (range: 180-745 minutes) with a median transfusion rate of 4 packed red blood cell units (range: 0-23 units). The cumulative sum learning curve identified 3 phases: an initial phase (1-70 piggyback liver transplantations), a plateau phase (71-101 piggyback liver transplantations), and a stable phase (102-181 piggyback liver transplantations). Over the 3 phases, there were significant decreases in the median duration of the surgery (388.8 vs 344.8 vs 326.9 minutes; P = .004, P = .0004, P ≤ .0001) and the number of red blood cell units transfused (6.00 vs 3.90 vs 3.71; P = .02, P = .79, P = .0006). Multivariable analysis identified that the following factors impacted the operative time: surgeon experience (P = .00006), previous upper abdominal surgery (P = .01), portocaval shunt fashioning (P = .0003), early portal section (P = .00001), multiple arterial graft reconstruction (P = .03), and the length of the retrohepatic inferior vena covered by segment 1 (P = .0006). Independent risk factors for increased blood loss were surgeon experience (P = .0001), previous upper abdominal surgery (P = .002), the retrohepatic inferior vena cava encirclement by segment 1 (P = .0001), severe portal hypertension (P = .01), early portal section (P = .001), and low prothrombin time (P = .00001).

CONCLUSION

Easily identifiable factors related to recipients (segment 1 morphology, previous upper abdominal surgery, severe portal hypertension) and to surgeon (operative experience, portocaval shunt fashioning, early portal section, and multiple arterial reconstructions) impact operative time and blood loss during the learning curve of piggyback liver transplantation. These factors can be used for grading the difficulties of liver transplantation to tailor the surgical strategy.

Imaging post liver transplantation part I: vascular complications

Liver transplantation continues to rise in frequency, with over 1,000 procedures performed in the UK in 2018. Complications are increasingly uncommon but when they occur, early recognition and intervention is vital to save grafts. Imaging after the perioperative period is often performed at patients' local hospitals meaning that all radiologists and sonographers need to have an understanding of how to assess a transplant liver. Part I of this series will focus on vascular complications, including the normal postoperative vascular anatomy following liver transplantation, normal post-transplantation vascular imaging findings and abnormal findings that may prompt further investigation. Vascular complications following liver transplantation will be illustrated using a collection of cases.