Liver transplantation in children: the experience of Queen Mary Hospital, Hong Kong

Systematic Review and Meta-Analysis of the Outcomes After Hepatic Artery Reconstruction in Pediatric Liver Transplantation Using a Microscope Versus Surgical Loupe

BACKGROUND

To review the impact of the operating microscope (OM) for reconstruction of the hepatic artery (HA) by comparing the outcomes with standard loupe reconstruction (SL) in pediatric liver transplantation (LT).

METHODS

Studies comparing the application of OM and SL for the reconstruction of the HA in primary pediatric LT were included from a systematic search of MEDLINE, Cochrane Library and EMBASE from inception to June 2022. Re-transplantation, dual grafts and auxiliary transplants were excluded. Primary outcome was the rate of HA thrombosis (HAT). Secondary outcomes were graft loss and mortality.

RESULTS

There were 1261 liver recipients from 9 included studies published until June 2022. There were 484 patients in the OM group and 777 patients in the SL group. HAT incidence with OM was significantly lower with OR = 0.18 (95% CI: 0.07-0.48). The 1-year graft survival was significantly better in the OM group with OR = 2.77 (95% CI: 1.13-6.80). 1-year overall mortality was also significantly lower with OM with OR = 0.39 (0.18-0.86). The use of OM did not significantly impact the incidence of HAT in the living donor liver transplant subgroup. Differences in time for hepatic HA reconstruction, total operating time and length of hospital stay did not reach statistical significance.

CONCLUSION

The use of OM has reduced the risk of HAT, graft loss and mortality in pediatric liver transplantation. Adoption of microsurgical principles in general may have contributed to the improved outcomes with SL reconstruction of HA in pediatric LT.

Hepatic Artery Microvascular Anastomosis in Liver Transplantation: A Systematic Review of the Literature

BACKGROUND

The operating microscope is used in many centers for microvascular hepatic arterial reconstruction in living as well as deceased donor liver transplantation in adult and pediatric recipients. To date, a systematic review of the literature examining this topic is lacking.

METHODS

This systematic review of the literature was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. Three different electronic databases (PubMed, Embase OVID, and Cochrane CENTRAL) were queried.

RESULTS

A total of 34 studies were included. The rate of hepatic artery thrombosis (HAT) in noncomparative studies (28) ranged from 0% to 10%, with 8 studies reporting patient deaths resulting from HAT. Within comparative studies, the rate of HAT in patients who underwent arterial reconstruction using the operating microscope ranged from 0% to 5.3%, whereas the rate of HAT in patients who underwent arterial reconstruction using loupe magnification ranged from 0% up to 28.6%, and 2 studies reported patient deaths resulting from HAT. Two comparative studies did not find statistically significant differences between the 2 groups.

CONCLUSIONS

Our comprehensive systematic review of the literature seems to suggest that overall, rates of HAT may be lower when the operating microscope is used for hepatic arterial reconstruction in liver transplantation. However, matched comparisons are lacking and surgical teams need to be mindful of the learning curve associated with the use of the operating microscope as compared with loupe magnification, as well as the logistical and time constraints associated with setup of the operating microscope.

Microvascular Hepatic Artery Anastomosis in Pediatric Living Donor Liver Transplantation: 73 Consecutive Cases Performed by a Single Surgeon

BACKGROUND

Living donor liver transplantation is an important strategy of procuring segmental liver allografts for pediatric patients with liver failure, as suitably sized whole donor organs are scarce. The early pediatric living donor liver transplantation experience was associated with high rates of hepatic artery thrombosis, graft loss, and mortality. Collaboration with microsurgeons for hepatic artery anastomosis in pediatric living donor liver transplantation has decreased rates of arterial complications; however, reported outcomes are limited.

METHODS

A 14-year retrospective review was undertaken of children at the authors' institution who underwent living donor liver transplantation with hepatic artery anastomosis performed by a single microsurgeon using an operating microscope. Data were collected on demographics, cause of liver failure, graft donor, vessel caliber, vessel anastomosis, arterial complications, and long-term follow-up.

RESULTS

Seventy-three children with end-stage liver failure underwent living donor liver transplantation with microvascular hepatic artery anastomosis. The commonest cause for liver failure was biliary atresia (63 percent). A total of 83 end-to-end hepatic artery anastomoses were completed using an operating microscope. Hepatic artery complications occurred in five patients, consisting of three cases of kinked anastomoses that were revised without complications and two cases of hepatic artery thrombosis (3 percent), of which one resulted in graft loss and patient death. Patient survival was 94 percent at 1 year and 90 percent at 5 years.

CONCLUSIONS

Microvascular hepatic artery anastomosis in pediatric patients undergoing living donor liver transplantation is associated with a low hepatic artery complication rate and excellent long-term liver graft function. Collaboration between microsurgeons and transplant surgeons can significantly reduce technical complications and improve patient outcomes.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.

A new simplified technique of arterial reconstruction in pediatric living-donor liver transplantation: a comparison with the classical technique

BACKGROUND/AIM

Hepatic artery anastomosis (HAA) is the most important aspect of living donor liver transplantation (LDLT), and it is currently performed by a specialized microsurgeon using micro surgical techniques, with interrupted sutures and the aid of an operative microscope. To simplify the procedure, we studied a new, simpler technique performed by pediatric transplant surgeons with continuous sutures and the same 3.5× magnification loupe used during other transplant procedures. The aim of this study was to compare these two hepatic artery reconstruction techniques in two pediatric LDLT series.

METHODS

This study was initiated in January 2010 and finished in June 2013. In the first period, the arterial reconstruction was performed with an operating microscope and the classical technique of 9-0 separate sutures. In the second period, the arterial reconstruction was performed using a simpler technique, with surgical loupe and continuous 8-0 Prolene sutures. The incidences and outcomes of complications within the two periods were analyzed and compared.

RESULTS

A total of 82 LDLTs were performed, 38 in the first period and 44 in the second period. There were no differences between the periods, except for the arterial ischemia time, which was lower in the second period.

CONCLUSION

Hepatic artery anastomosis can be safely performed with low complication rates by a pediatric transplant surgeon using continuous sutures with a 3.5× magnifying loupe. This technique is simpler, less time consuming and simplifies the complex pediatric LDLT procedure.

Liver transplantation in children weighing 5 kg or less: analysis of the UNOS database

LT is a major medical and surgical challenge in very small patients. Aim of the study is to determine the outcomes after LT in infants ≤ 5 kg at transplant in a large cohort of patients.

METHODS

Infants ≤ 5 kg who had LT between 10/1987 and 5/2008 were identified from the UNOS database. Risk factors for death and graft loss were analyzed by multivariate logistic regression.

RESULTS

Of 11,467 children, 570 (5%) were ≤ 5 kg at LT. Mean age and weight at LT were 0.11 ± 0.48 yr, 4.32 ± 0.74 kg, respectively. One- and five-yr patient and graft survival were 77.7%, 72.2% and 66.1%, 57.6%, respectively. The primary cause of death was infection (25.9%). Recipient age was a predictor of graft loss. Patient and graft survival have improved over time. Life support at transplant was identified as a risk factor for both death and graft loss (p < 0.02, p < 0.01, respectively).

CONCLUSION

LT recipients ≤5 kg have high mortality and graft loss. Over time, graft survival has improved, although it is still inferior to the overall reported outcomes of pediatric LT. Being on life support at transplant is a significant risk factor for death and graft loss in very small recipients.

Liver Transplantation for Small Babies

Orthotopic liver transplantation remains a major medical and surgical challenge in small pediatric patients. From April 2003 to June 2006, 21 small babies (each of whom weighed less than 10 kg or was younger than 1 year of age) underwent orthotopic liver transplantation. Five were girls and 16 were boys with a mean age of 15.7 +/- 9.3 months (range, 2-24 months); their mean weight at the time of transplantation was 9.8 +/- 3.6 kg (range, 6-16 kg). All transplants were obtained from a living-related donor. Left lateral segment was used for all transplantations. The median graft-to-recipient weight ratio was 3.5% +/- 1.2% (range, 1.5%-6.1%). During the early postoperative period, hepatic arterial thrombosis was identified in 4 patients, and a biliary leak was detected in 2 patients. In 2 patients, portal vein stenosis was identified during the late postoperative period. At the time of this writing, the 17 alive patients (81%) exhibited good graft function at median follow-up of 14.8 +/- 10.9 months (range, 1-39 months). Four patients died during the follow-up. Histological examination revealed hepatocellular carcinoma in 2 patients, and Burkitt's lymphoma in 1 patient. In conclusion, our data confirmed that living-related donors, especially in this age group, provide a reliable source for the organ pool. Satisfactory results can be achieved despite the anatomic handicaps of this age group.

Liver Transplantation in Children Weighing Less Than 10 Kilograms

Orthotopic liver transplantation (OLT) remains a major medical and surgical challenge in small pediatric patients. From April 2003 through October 2005, 17 infants (each of whom weighed less than 10 kg) underwent the procedure. Four were girls and 13 were boys (mean age, 15.7 +/- 9.3 months [range, 2-36 months]; mean weight at the time of transplantation, 7.4 +/- 2.6 kg [range, 6-10 kg]). All transplants were obtained from living-related donors. Sixteen left lateral segments and 1 left lobe were transplanted. The median graft-to-recipient weight ratio was 3.5% +/- 1.2% (range, 1.5%-6.1%). During the early postoperative period, hepatic arterial thrombosis was identified in 2 infants, and a biliary leak in 1. Hepatic arterial thrombosis was treated by reanastomosis with polytetrafluoroethylene grafting in the first patient and by surgical embolectomy in the second. The biliary leak was treated with percutaneous drainage. In 1 infant, portal vein stenosis, which was identified during the late postoperative period, was treated by percutaneous balloon dilatation. At this time, 14 (82.3%) infants were alive, exhibiting good graft function at a median follow-up of 11 months (range, 2-36 months). Three infants died: 1 on postoperative day 47 from adult respiratory distress syndrome, 1 on postoperative day 12 from sepsis, and 1 on postoperative day 65 from sepsis associated with EBV infection. Episodes of acute rejection, which occurred in 5 patients, were treated with pulse steroid therapy. On follow-up, histologic examination revealed hepatocellular carcinoma in 2 infants and Burkitt's lymphoma in 1 infant. Our data confirm that extensive use of living-related donors in liver transplantation can result in an excellent outcome for small pediatric patients.

Microvascular hepatic artery anastomosis in pediatric segmental liver transplantation: microscope vs loupe

Use of operative microscopy (OM) has dramatically reduced the incidence of hepatic artery thrombosis (HAT) in children undergoing segmental liver transplantation. We used OM (12-16x) in our early experience. We changed to high power loupe magnification (6x) after 14 cases. We examined our experience with microvascular hepatic artery reconstruction in 28 consecutive children (< 18 years) who underwent living donor (LDLT) or split liver transplantation (SLT). Reconstructions were done with interrupted, end-to-end anastomoses with 8-0 polypropylene using microvascular techniques. Group 1 consisted of 14 children who underwent LDLT employing OM for the hepatic artery anastomosis. Group 2 consisted of the subsequent 14 children (11 LDLT, 3 SLT) in whom 6x loupe optics were used for the arterial anastomosis. Grafts included 25 left lateral segments, 2 left lobes, and 1 right lobe. Recipients' median age was 1.0 years (range 3 months to 17 years). The mean follow-up time was 27.1 months. There were no cases of HAT. Variables of age, sex, graft type, number of Doppler ultrasound exams (DUS), and biliary complications were similar between groups. Microvascular hepatic artery reconstruction in children with 6x loupe magnification can yield results as good as operative microscopy.

Liver transplantation in infants weighing under 7 kilograms: management and outcome of PICU

Liver transplantation (LT) is an established treatment for children with acute and chronic liver failure. Some reports suggest that infants under the age of 1 yr and children weighing under 13 kg are high-risk groups associated with less satisfactory results. This report describes our experience during the pediatric intensive care unit stay of 16 infants weighing <7 kg who received LT. We reviewed the records of 16 infants with median age 7.4 months and median weight 5.8 kg, who received 18 liver allografts, nine whole and nine reduced. We also reviewed the use of adrenergic agonist agents, anti-infectious agents, antihypertensive agents, diuretics, immunosuppression protocol, sedation-analgesia agents, others agents (prostaglandin E(1), heparin and dipyridamole), diagnosis and management of rejection episodes, follow-up examination, nutrition and outcome. Mean peri-operative blood transfusions were 204 mL/kg, 188 mL/kg of plasma and 36 mL/kg of platelets; mean operative time was 5 h. Primary abdominal wound closure was possible in nine patients. Median initial intensive care unit stay was 18 days. Reasons for an initial stay of more than 18 days were retransplantation (1), gastrointestinal bleeding (2), paralytic ileus and atelectasis (2), septic shock (2), diaphragmatic paralysis, renal impairment and acute respiratory distress syndrome (2). Mean requirement for artificial ventilation was 168 h. Mean use of dobutamine, prostaglandin E(1) and dopamine was 3.3, 7.5 and 8.8 days, respectively. Parenteral nutrition was started at a mean of 48 h and oral food intake was started at a mean of 72 h. The most frequent complications were infection, atelectasis, gastrointestinal bleeding, acute renal failure and hepatic artery thrombosis. Four children required six re-explorations and two received retransplantation. Mean overall survival rate was 82% and graft survival was 72%. Weight alone (under 7 kg) should not be considered as a contraindication for LT. The survival rate of children post-LT is excellent regardless of graft type.

Right-lobe living related liver transplantation: evaluation of a comprehensive magnetic resonance imaging protocol for assessing potential donors

The purpose of this study was to determine the practicability and diagnostic accuracy of a magnetic resonance (MR) protocol capable of replacing computed tomography, catheter angiography, and endoscopic retrograde cholangiopancreatography for the presurgical evaluation of potential liver donors before right hepatectomy. MR imaging (MRI) was performed on a 1.5 T scanner using a phased-array torso surface coil for signal reception. The following image sets were collected: axial two-dimensional (2D) T1-weighted fast low angle shot (FLASH), axial 2D T2-weighted half-Fourier acquisition single-shot turbo-spin-echo (HASTE) with fat saturation, coronal MR cholangio-pancreatography (MRCP) based on 2D multisection HASTE and single-section single-shot rapid acquisition with relaxation enhancement (RARE) imaging, dynamic contrast-enhanced three-dimensional (3D) FLASH, and contrast-enhanced T1-weighted FLASH. 3D FLASH data sets were collected before and after an intravenous administration of Multihance (gadobenate dimeglumine, Gd-BOPTA; Bracco, Milano, Italy), 0.2 mmol/kg of body weight. Thirty-eight potential liver donors were assessed by means of MRI. Twenty patients also underwent digital subtraction angiography (DSA). Of these, 16 patients underwent liver harvesting. MR angiography (MRA) data sets correlated with DSA results, and MRCP results correlated with intraoperative findings. Patients were excluded as potential donors based on insufficient liver mass of the left hepatic lobe (n = 5) or presence of hepatic pathological states (n = 9) seen at MRI, such as hemangiomas, focal nodular hyperplasias, or hepatic steatosis. MRCP showed the biliary system to the level of the first hepatic side branch. Dilated ducts were present in 4 patients. MRA depiction of hepatic arterial morphological characteristics correlated with catheter angiography results in all 20 patients: Three left hepatic arteries originating from the left gastric artery, three aberrant right hepatic arteries originating from the superior mesenteric artery, and two aberrant origins of both hepatic arteries and one common hepatic artery originating from the superior mesenteric artery were correctly identified on MRA. Similarly, the portal venous system was fully assessed on MRA. A comprehensive assessment of the hepatic parenchyma, biliary and pancreatic ductal system, and hepatic arterial, portal, and venous systems can be accomplished using the outlined protocol.