Vascular complications in living donor liver transplantation at a high-volume center: Evolving protocols and trends observed over 10 years

Safety and efficacy of extended thrombophilia screening directed venous thromboembolic events (VTE) prophylaxis in live liver donors: do we really need extended thrombophilia screening routinely?

Background and aims

The study aimed to determine the prevalence of hereditary thrombophilia, and stratify its severity among live liver donors in Pakistan. Also, the authors evaluated the safety and efficacy of thrombophilia profile testing directed venous thromboembolic events (VTE) prophylaxis while balancing bleeding risk and the need for routine thrombophilia testing before live liver donation among living donor candidates.

Materials and methods

Protein S (PS), protein C (PC), anti-thrombin (AT) III, and anti-phospholipid antibody panel (APLA) levels were measured in 567 potential donor candidates. Donors were divided into normal, borderline and high-risk groups based on Caprini score. The safety endpoints were VTE occurrence, bleeding complications or mortality.

Results

Among 567 donors, 21 (3.7%) were deficient in protein C, and 14 (2.5%) were deficient in anti-thrombin-III. IgM and IgG. Anti-phospholipids antibodies were positive in 2/567 (0.4%) and 2/567 (0.4%), respectively. IgM and IgG lupus anticoagulant antibodies were positive in 3/567 (0.5%) and 3/567 (0.5%), respectively. VTE events, bleeding complications and postoperative living donors liver transplantation-related complications were comparable among the three donor groups (P>0.05). One donor in the normal donor group developed pulmonary embolism, but none of the donors in either borderline or high-risk group developed VTE. The mean length of ICU and total hospital stay were comparable. No donor mortality was observed in all donor groups.

Conclusions

Due to thrombophilia testing directed VTE prophylaxis, VTE events were comparable in normal, borderline and high-risk thrombophilia donor groups, but more evaluations are required to determine the lower safe levels for various thrombophilia parameters including PC, PS and AT-III before surgery among living donor candidates.

HPi: A Novel Parameter to Predict Graft-related Outcome in Adult Living Donor Liver Transplant

BACKGROUND

Portal hyperperfusion is frequently associated with early allograft dysfunction (EAD). It is imperative to identify patients who would require portal inflow modulation. We aimed to identify factors associated with hyperperfusion-related graft injury and develop a predictive index for the same.

METHODS

Prospectively maintained database was queried to identify 135 adult living donor liver transplant recipients between September 2016 and July 2020. According to the calculated sample size, 96 patients were randomly selected for "test cohort". The remaining 39 patients made the "validation cohort." EAD was defined according to the A2ALL study. "Hyperperfusion index (HPi)," defined as posttransplant portal pressure gradient (ΔPpost)/graft-to-recipient splenic volume ratio (GRSVR), was devised on the basis of laws of flow dynamics and regression analysis.

RESULTS

Overall, 40 patients (29.6%) had EAD, six 90-d mortalities (4.4%) were attributable to EAD. In the test cohort, EAD patients (n = 29, 30.2%) had lower GRSVR (1.00 versus 2.22, P < 0.001), higher ΔPpost (14.8 versus 11.9, P = 0.004), and HPi (20.89 versus 8.67, P < 0.001). Multivariate analysis revealed GRSVR, ΔPpost, and HPi as significant factors to predict EAD. Receiver operating characteristic determined cutoff of HPi ≥9.97 could predict EAD with sensitivity of 90% and specificity of 73% (F-score = 0.712). HPi ≥16.25 predicted 90-d mortality with sensitivity of 100% and specificity of 78.9%. Patients with higher HPi had delayed graft-related recovery. Non-EAD patients had a higher 1-y (96% versus 79%) and 2-y (88% versus 79%) survival. The cutoff of HPi was validated well in the validation cohort (F-score = 0.645) (Hosmer-Lemeshow test, P = 0.89).

CONCLUSIONS

While predicted GRSVR may help identify at-risk patients preoperatively, intraoperatively calculated HPi is more accurate in identifying patients who would require portal inflow modulation. Achieving an HPi below target cutoff significantly decreases the risk of EAD even in low-GRSVR patients.

Delayed sequential abdominal wall closure in pediatric liver transplantation to overcome "large for size" scenarios

BACKGROUND

Primary abdominal wall closure after pediatric liver transplantation (PLT) is neither always possible nor advisable, given the graft-recipient size discrepancy and its potential large-for-size scenario. Our objective was to report the experience accumulated with delayed sequential closure (DSC) guided by Doppler ultrasound control.

METHODS

Retrospective analysis of DSC performed from 2013 to March 2020.

RESULTS

Twenty-seven DSC (26.5%) were identified out of 102 PLT. Transplant indications and type of grafts were similar among both groups. In patients with DSC, mean weight and GRWR were 9.4 ± 5.5 kg (3.1-26 kg) and 4.7 ± 2.4 (1.9-9.7), significantly lower and higher than the primary closure cohort, respectively. The median time to achieve definitive closure was 6 days (range 3-23 days), and the median number of procedures was 4 (range 2-9). Patients with DSC had longer overall PICU (22.5 ± 16.9 vs. 9.1 ± 9.7 days, p < .05) and hospital stay (33.4 ± 19.1 vs 23, 9 ± 19.8 days (p < .05). These differences are less remarkable if the analysis is performed in a subgroup of patients weighing less than 10 kg. Two patients presented vascular complications (7.4%) within DSC group. No differences were seen when comparing overall, 3-year graft and patient survival (96% and 96% in the DSC group).

CONCLUSIONS

DSC is a simple and safe technique to ensure satisfactory clinical outcomes to overcome "large for size" scenarios in PLT. In addition, we were able to avoid using a permanent biological material for closing the abdomen.

Do Natural Portosystemic Shunts Need to Be Compulsorily Ligated in Living Donor Liver Transplantation?

BACKGROUND

Natural portosystemic shunt ligation practices in liver transplant vary widely across transplant centres and are frequently undertaken to prevent the serious consequence of portal steal phenomenon. No concrete indications have so far been convincingly identified for their management in living donor liver transplant.

METHODS

We retrospectively studied the outcome of 89 cirrhotic patients who either did (n = 63) or did not (n = 25) undergo shunt ligation during living donor liver transplantation between 2017 and 2020.

RESULTS

The incidence of early allograft dysfunction/nonfunction (P = 1.0) and portal venous complications (P = 0.555) were similar between the two groups. Although overall complications, biliary complications, and the composite of Grade III and IV complications were significantly higher in the nonligated group (P = 0.015, 0.052 and 0.035), 1- year graft and patient survival were comparable between them (P = 0.524).

CONCLUSION

We conclude that shunt ligation in living donor liver transplantation may not always be necessary if adequate portal flow, good vascular reconstruction, and good graft quality have been ensured.

Cystic duct anastomosis can be a viable option for biliary reconstruction in case of multiple ducts in right lobe living-donor liver transplantation

Backgrounds/Aims

Multiple ducts in right lobe living-donor liver transplant (LDLT) pose a technical challenge in biliary reconstruction. In the absence of separate recipient hepatic ducts for duct-to-duct anastomoses and certain demerits of hepaticojejunostomy, duct to duct anastomoses with the recipient cystic duct might be a possible solution.

Methods

A total of 329 recipients of LDLT who underwent two or more separate biliary anastomoses at our centre between January 2014 and November 2019 were studied retrospectively. Records of demographic data, donor and graft characteristics, operative details, postoperative biochemical parameters, and biliary complications were analysed.

Results

Of 329 recipients, 236 patients (71.7%) underwent purely duct-to-duct (DD group) anastomoses, 38 patients (11.5%) underwent at least one anastomosis with the cystic duct (CD group), and 55 patients (16.7%) underwent at least one hepaticojejunostomy (HJ group). At one year, biliary complication rates of these three groups were 20.3%, 26.3%, and 20.0%, respectively (p = 0.68). Postoperative intensive care unit and overall hospital stay were similar among the three groups. Grades IIIa, IIIb, IV, and V Clavien-Dindo complications were identical. One-year patient survival and graft survival were also similar among the three groups.

Conclusions

Biliary outcomes using the cystic duct may have acceptable outcomes. Similar postoperative results as other means of biliary reconstruction could be anticipated with the cystic duct anastomoses in case of multiple ducts in the graft.

Meta-analysis and meta-regression of outcomes for adult living donor liver transplantation versus deceased donor liver transplantation

Prior single center or registry studies have shown that living donor liver transplantation (LDLT) decreases waitlist mortality and offers superior patient survival over deceased donor liver transplantation (DDLT). The aim of this study was to compare outcomes for adult LDLT and DDLT via systematic review. A meta-analysis was conducted to examine patient survival and graft survival, MELD, waiting time, technical complications, and postoperative infections. Out of 8600 abstracts, 19 international studies comparing adult LDLT and DDLT published between 1/2005 and 12/2017 were included. U.S. outcomes were analyzed using registry data. Overall, 4571 LDLT and 66,826 DDLT patients were examined. LDLT was associated with lower mortality at 1, 3, and 5 years posttransplant (5-year HR 0.87 [95% CI 0.81-0.93], p < .0001), similar graft survival, lower MELD at transplant (p < .04), shorter waiting time (p < .0001), and lower risk of rejection (p = .02), with a higher risk of biliary complications (OR 2.14, p < .0001). No differences were observed in rates of hepatic artery thrombosis. In meta-regression analysis, MELD difference was significantly associated with posttransplant survival (R2 0.56, p = .02). In conclusion, LDLT is associated with improved patient survival, less waiting time, and lower MELD at LT, despite posing a higher risk of biliary complications that did not affect survival posttransplant.

Outcome of Pediatric Liver Transplants in Patients With Less Than 10 kg of Body Weight Is Not Worse

OBJECTIVES

Liver transplant in pediatric patients with body weight < 10 kg poses a challenge to the entire liver transplant team. Many reports have considered 10 kg to be a cutoff pointfor body weightforfavorable posttransplant outcomes. With evolving surgical techniques and postoperative management, there is potential to improve outcomes in this subset of recipients. We compared the outcomes in pediatric patients with body weight < 10 kg with those > 10 kg; also, we studied the factors of influence.

MATERIALS AND METHODS

We performed a retrospective analysis to evaluate the outcomes of liver transplants in pediatric patients with < 10 kg body weight. The cohort consisted of 90 children subdivided into the following 2 subgroups: group A (n = 35) with > 10 kg body weight at liver transplant and group B (n = 55) with < 10 kg body weight at liver transplant. We compared the following pretransplant characteristics between the groups: graft weight, graft-to-recipient weightratio, cold ischemia time, warm ischemia times, and liver transplant outcomes.

RESULTS

Pediatric End-stage Liver Disease score was significantly higher in group B (score of 24) versus group A (score of 18). Group B had significantly higher graft-to-recipient weight ratio (2.8 in group B vs 1.7 in group A). Graft function showed no significant difference between the 2 groups. Portal vein thrombosis was seen only in group B, whereas biliary leaks were observed among 5 patients in group B and 1 patientin group A. Patient survivalrate was higherin group B (86%) than in group A (77%).

CONCLUSIONS

Pediatric patients weighing < 10 kg have similarif not better survivalrates after liver transplant compared with patients > 10 kg. Advancements in surgical techniques and a careful monitoring for complications and timely intervention are important to facilitate these outcomes.

Liver Transplantation for Propionic Acidemia: Evidence from A Systematic Review and Meta-analysis

BACKGROUND

The worldwide experience of liver transplantation (LT) in the treatment of propionic acidemia (PA) remains limited and fragmented. This review aims to provide a comprehensive and quantitative understanding of post-transplant clinical outcomes in PA patients.

METHODS

MEDLINE, Embase and the Cochrane Library databases were searched for studies focusing on PA patients who underwent LT. The pooled estimate rates and 95% confidence intervals (CIs) were calculated using a random-effects model with Freeman-Tukey double arcsine transformation.

RESULTS

Twenty-one studies involving 70 individuals were included. The pooled estimate rates were 0.95 (95% CI, 0.80-1.00) for patient survival and 0.91 (95% CI, 0.72-1.00) for allograft survival. The pooled estimate rates were 0.20 (95% CI, 0.05-0.39) for rejection, 0.08 (95% CI, 0.00-0.21) for hepatic artery thrombosis, 0.14 (95% CI, 0.00-0.37) for cytomegalovirus/Epstein-Barr virus infection and 0.03 (95% CI, 0.00-0.15) for biliary complications. The pooled estimate rates were 0.98 (95% CI, 0.88-1.00) for metabolic stability, 1.00 (95% CI, 0.79-1.00) for reversal of pre-existing cardiomyopathy and 0.97 (95% CI, 0.78-1.00) for improvement of neurodevelopmental delay. A large proportion of patients achieved liberalization of protein intake posttransplant [pooled estimate rate 0.66 (95% CI, 0.35-0.93)].

CONCLUSIONS

Despite the risk of transplant-related complications, LT is a viable therapeutic option in PA patients, with satisfactory survival rates and clinical outcomes. Given the diversity in neurological assessment methods and the inconsistency in achievement of dietary protein liberalization across different studies, consensus on neurological evaluation methods and post-transplant protein intake is necessary. Longer-term clinical outcomes of LT for PA warrants further investigation.

Hepatic artery reconstruction in pediatric liver transplantation: Experience from a single group

BACKGROUND

The reconstruction of hepatic artery is a challenging part of the pediatric liver transplantation procedure. Hepatic artery thrombosis (HAT) and stenosis are complications which may result in ischemic biliary injury, causing early graft lost and even death.

METHODS

Two hundred and fifty-nine patients underwent liver transplantation in 2017 in a single liver transplantation group. Among them, 225 patients were living donor liver transplantation (LDLT) and 34 deceased donor liver transplantation (DDLT).

RESULTS

In LDLT all reconstructions of hepatic artery were microsurgical, while in DDLT either microsurgical reconstruction or traditional continuous suture technique was done depending on different conditions. There were five (1.9%) HATs: four (4/34, 11.8%) in DDLT (all whole liver grafts) and one (1/225, 0.4%) in LDLT (P = 0.001). Four HATs were managed conservatively using anticoagulation, and 1 accepted salvage surgery with re-anastomosis. Until now, 3 HAT patients remain in good condition, whereas two developed biliary complications. One of them needed to be re-transplanted, and the other patient died due to biliary complications.

CONCLUSIONS

Microsurgical technique significantly improves the reconstruction of hepatic artery in pediatric liver transplantation. The risk for arterial complications is higher in DDLT. Conservative therapy can achieve good outcome in selected HAT cases.

Outcome after pediatric liver transplantation for staged abdominal wall closure with use of biological mesh-Study with long-term follow-up

Abdominal wall closure after pediatric liver transplantation (pLT) in infants may be hampered by graft-to-recipient size discrepancy. Herein, we describe the use of a porcine dermal collagen acellular graft (PDCG) as a biological mesh (BM) for abdominal wall closure in pLT recipients. Patients <2 years of age, who underwent pLT from 2011 to 2014, were analyzed, divided into definite abdominal wall closure with and without implantation of a BM. Primary end-point was the occurrence of postoperative abdominal wall infection. Secondary end-points included 1- and 5-year patient and graft survival and the development of abdominal wall hernia. In five out of 21 pLT recipients (23.8%), direct abdominal wall closure was achieved, whereas 16 recipients (76.2%) received a BM. BM removal was necessary in one patient (6.3%) due to abdominal wall infection, whereas no abdominal wall infection occurred in the no-BM group. No significant differences between the two groups were observed for 1- and 5-year patient and graft survival. Two late abdominal wall hernias were observed in the BM group vs none in the no-BM group. Definite abdominal wall closure with a BM after pLT is feasible and safe when direct closure cannot be achieved with comparable postoperative patient and graft survival rates.

Projected 20- and 30-Year Outcomes for Pediatric Liver Transplant Recipients in the United States

BACKGROUND

Observed long-term outcomes no longer reflect the survival trajectory facing pediatric liver transplant (LT) recipients today. We aimed to use national registry data and parametric models to project 20- and 30-year post-transplant outcomes for recently transplanted pediatric LT recipients.

METHODS

We conducted a retrospective cohort study of 13,442 first-time pediatric (age <18) LT recipients using 1987 to 2018 Scientific Registry of Transplant Recipients data. We validated the proposed method (ie, to project long-term patient and graft survival using parametric survival models and short-term data) in 2 historic cohorts (1987-1996 and 1997-2006) and estimated long-term projections among patients transplanted between 2007 and 2018. Projections were stratified by raft type, recipient age, and indication for transplant.

RESULTS

Parsimonious parametric models with Weibull distribution can be applied to post-transplant data and used to project long-term outcomes for pediatric LT recipients beyond observed data. Projected 20-year patient survival for pediatric LT recipients transplanted in 2007 to 2018 was 84.0% (95% confidence interval 81.5-85.8), compared to observed 20-year survival of 72.8% and 63.6% among those transplanted in 1997 to 2006 and 1987 to 1996, respectively. Projected 30-year survival for pediatric LT recipients in 2007 to 2018 was 80.1% (75.2-82.7), compared to projected 30-year survival of 68.6% (66.1-70.9) in the 1997 to 2006 cohort and observed 30-year survival of 57.5% in the 1987 to 1996 cohort. Twenty- and 30-year patient and graft survival varied slightly by recipient age, graft type, and indication for transplant.

CONCLUSIONS

Projected long-term outcomes for recently transplanted pediatric LT recipients are excellent, reflective of substantial improvements in medical care, and informative for physician-patient education and decision making in the current era.

Dissection of the Hepatic Artery: A Rare Cause of Late Ischemia After Liver Transplant

Hepatic artery dissection is an infrequent vascular complication that can arise after orthotopic liver transplant. Most patients with this complication are diagnosed during the intraoperative period or the first days after liver transplant, with an association shown with living-donor liver transplant. In this study, we discuss a rare case of an extrahepatic artery dissection that was successfully managed through surgical excision and arterial revascularization that was diagnosed 4 years after orthotopic liver transplant. Furthermore, we hypothesize on the potential causes of its occurrence.

Antithrombotic management and thrombosis rates in children post-liver transplantation: A case series and literature review

Thrombosis is a major postoperative complication in pediatric liver transplantation. There is marked heterogeneity in prophylactic antithrombotic therapies used, without established guidelines. This review summarizes current worldwide incidence of thrombotic events and compares antithrombotic therapies in children post-liver transplant, with comparison to our institution's experience. Of the twenty-three articles with sufficient detail to compare antithrombotic regimens, the overall incidence of thrombosis ranged from 2.4% to 17.3%. Incidence of HAT ranged from 0% to 28.1%, of HVT from 0% to 4.7%, of PVT from 1.5% to 11.2%, and of IVC thrombosis from 0% to 2.8%. Re-transplantation due to thrombosis ranged from 0% to 4.8%. Prophylactic antithrombotic therapies varied between studies, and bleeding complications were infrequently reported. Since 2010, 96 children underwent 100 liver transplants at our institution with thrombosis incidence comparable to international literature (HAT 6%, PVT 5%, IVC 1%, and HVT 0%). Re-transplantation due to thrombosis occurred in 2% and major bleeding occurred in 10%. The prophylactic antithrombotic therapies used post-liver transplantation in children remain varied. Low rates of thrombosis have been reported with antiplatelet use both with and without anticoagulation. Standard definitions and consistent reporting of bleeding complications are required, in addition to thrombosis rates, so that true risk-benefit assessment of reported regimes can be understood.

Contrast-Enhanced Ultrasound for identifying circulatory complications after liver transplants in children

Our main goal with this study was to share our off-label experience with CEUS for identifying circulatory complications after liver transplantation in children. A total of 74 CEUS examinations performed on 34 pediatric patients who underwent a liver transplant were retrospectively included. About 53% of the examinations were performed on children 2 years old or younger. About 82% of the examinations were performed within 30 days from the transplant. About 62% of patients were transplanted due to a cholestatic disease, 11% due to a metabolic disease, 8% were re-transplanted due to graft failure, and 19% was due to other conditions. BA was the most common reason for transplantation and represented 38% of patients. About 38% of the transplantations were performed with whole grafts from DD, 40% with split liver grafts, and 22% with left lateral segments from LD. For diagnosing arterial circulatory complications, the PPV was 80%. For diagnosing portal vein circulatory complications, the PPV was 66.7%. NPV was 100%. In 28% of the examinations, the examiner could not visualize the normal arterial blood flow without CEUS. CEUS is a non-invasive and safe imaging technique that seems valuable in these patients and further efforts are needed to license its use in the post-transplant setting.

Critical Care Management of Living Donor Liver Transplants

This article represents a review of the postoperative management of donors and recipients after living donor liver transplant, including monitoring, liberation from mechanical ventilation, nutritional support, and pain control. Vascular complications, such as biliary and sepsis, and bleeding are also discussed. Finally, commonly used immunosuppression and antimicrobial prophylaxes are reviewed.

Splenectomy as Flow Modulation Strategy and Risk Factors of De Novo Portal Vein Thrombosis in Adult-to-Adult Living Donor Liver Transplantation

Portal vein thrombosis (PVT) is a severe complication after liver transplantation that can result in increased morbidity and mortality. Few data are available regarding risk factors, classification, and treatment of PVT after living donor liver transplantation (LDLT). Between January 2004 and November 2014, 421 adult-to-adult LDLTs were performed at our institution, and they were included in the analysis. Perioperative characteristics and outcomes from patients with no-PVT (n = 393) were compared with those with de novo PVT (total portal vein thrombosis [t-PVT]; n = 28). Ten patients had early portal vein thrombosis (e-PVT) occurring within 1 month, and 18 patients had late portal vein thrombosis (l-PVT) appearing later than 1 month after LDLT. Analysis of perioperative variables determined that splenectomy was associated with t-PVT (hazard ratio [HR], 3.55; P = 0.01), e-PVT (HR, 4.96; P = 0.04), and l-PVT (HR, 3.84; P = 0.03). In contrast, donor age was only found as a risk factor for l-PVT (HR, 1.05; P = 0.01). Salvage rate for treatment in e-PVT and l-PVT was 100% and 50%, respectively, without having an early event of rethrombosis. Mortality within 30 days did not show a significant difference between groups (no-PVT, 2% versus e-PVT, 10%; P = 0.15). No significant differences were found regarding 1-year (89% versus 92%), 5-year (79% versus 82%), and 10-year (69% versus 79%) graft survival between the t-PVT and no-PVT groups, respectively (P = 0.24). The 1-year (89% versus 96%), 5-year (82% versus 86%), and 10-year (79% versus 83%) patient survival was similar for the patients in the no-PVT and t-PVT groups, respectively (P = 0.70). No cases of graft loss occurred as a direct consequence of PVT. In conclusion, the early diagnosis and management of PVT after LDLT can lead to acceptable early and longterm results without affecting patient and graft survival.