Pediatric Orthotopic Liver Transplantation Research Articles

INCIDENCE, MANAGEMENT, AND OUTCOME OF SERIOUS PANCREATITIS FOLLOWING PEDIATRIC LIVER TRANSPLANTATION

344 Aim: The incidence and clinical impact of acute pancreatitis (AP) following pediatric orthotopic liver transplantation (OLTx) has not been well characterized. This report details the clinical presentation, management, and outcome of AP after pediatric OLTx. Methods: The case records of all pediatric liver recipients between January 1986 and October, 1997 were reviewed. Patients with clinical evidence of serious pancreatitis defined as presence of clinical signs, as well as positive findings on abdominal imaging or exploratory laparotomy were reviewed for survival, concomitant morbidities, clinical presentation, and outcome. Results: 634 pediatric OLTx were performed between January 1986 and October 1997. 26 patients with 33 episodes of serious AP were documented. Mean age at time of transplant was 7.7 years(range 8 months- 19 years). The indication for OLTx preceding the episodes of AP were fulminant failure in six, biliary atresia in 10, chronic rejection in 3 and other etiologies in 7. Only two patients had a pre-existing history of pancreatitis. Serious AP was more likely to occur early after OLTx (54% occurred within the first week) and was associated with the presence of an infra-renal aortic graft in 13/26 patients. AP was more likely to occur after a re-do OLTx (11/26 patients) and was associated with blood loss and difficult surgery in four cases. Associated morbidities were common and included acute renal failure in 15/26 (58%) patients, 10 of whom required hemodialysis or other renal support. Mortality was 42% (11/26). Cause of death was sepsis and multiple organ failure in nine and hemorrhage in two. Pathologic changes noted at diagnosis were edema in 17/26, hemorrhagic pancreatitis in 2, and necrotizing pancreatitis in 7/26. Complicated AP defined as subsequent abscess/pseudocyst/phlegmon developed in 8 and hemorrhagic changes in 4. AP was associated with graft failure in 5 patients, with ruptured arterial peudoaneursym/graft-enteric fistula and bleeding in 4/26 patients and infected arterial pseudoaneurysm (non-ruptured) in 1 patient. Of the five patients with graft failure related to pancreatitis, only one was able to be re-transplanted and none survived. Management of complicated AP included antibiotics, sphincterotomy, debridement with drainage, hepatic arterial revascularization/or arterial ligation. Open abdominal drainage and pancreatic resection was attempted without success in two cases with refractory sepsis. Chronic pancreatitis developed in one patient; the remaining survivors have been asymptomatic. Conclusion: Serious AP after pediatric OLTx can be a devastating complication that leads to graft failure in up to 15% (5/33) episodes and carries a high mortality. Risk factors include repeat OLTx and the presence of an infra-renal aortic graft. Management is primarily supportive but early drainage of abscess and control of intrabdominal sepsis is essential. Resectional therapy has been associated with a poor outcome in our experience.

PROGNOSTIC IMPLICATIONS OF CENTRILOBULAR NECROSIS IN PEDIATRIC LIVER TRANSPLANT RECIPIENTS1

We have observed centrilobular necrosis (CLN) in several liver allograft biopsies in our pediatric liver transplant population. The aims of this study were to describe the associated pathologic and clinical features of post-orthotopic liver transplantation CLN and determine its prognostic implications. CLN was identified and characterized in 44 allografts from 40 patients (17 males and 23 females) among our 443 pediatric recipients. Twenty episodes were associated with cellular rejection, either in the same biopsy (n=15) or within the week prior (n=5), and five were associated with ductopenic rejection. Twelve were associated with vascular thrombosis. No clear etiology was identified in seven episodes, but two also had cholangitis lenta. Of the remaining five biopsies, three showed only centrilobular dropout, suggesting a resolution of some previous insult. The outcome of 40 patients following an initial episode of CLN was poor, with graft failure in 33, chronic poor function in 2, and normal recovery in only 5 patients. The results of retransplantation for graft failure due to CLN were equally poor, with 14 deaths, 3 patients with ductopenic rejection, and only 5 with normal recovery. CLN recurred in four grafts. Overall patient outcome was very poor: 25 deaths; 3 ductopenic rejections; 2 chronic poorly functioning livers; and 10 patients alive and well. We conclude that CLN in pediatric orthotopic liver transplantation recipients is associated with cellular rejection, ductopenic rejection, or acute vessel thrombosis in the majority cases. The prognostic implications of CLN are grave, with high rates of graft failure requiring retransplantation and death.

Gastrointestinal perforation after pediatric orthotopic liver transplantation

Purpose: The aim of this review was to determine the incidence of gastrointestinal perforation after pediatric liver transplantation and to identify risk factors and clinical indicators that may lead to an earlier diagnosis. Methods: A retrospective chart review of all children who presented with gastrointestinal perforation after liver transplantation at our institution between January 1, 1987 and August 1, 1996 was performed. Results: One hundred fifty-seven orthotopic liver transplants were performed in 128 children. Fifty-eight reexplorations, excluding those for retransplantation, were performed in 38 children. Ten perforations occurred in six children (incidence, 6.4%). Two children required multiple reexplorations because of several episodes of perforation. The sites of perforation were duodenum (n = 1), jejunum (n = 8), and ileum (n = 1). A single-layer closures in four, and resection with primary anastomosis in another. The type of repair did not affect the occurrence of subsequent perforations. All the children were less than 18 months old. Four children had undergone prior laparotomy. All children had choledochoenteric anastomoses, but only one had a perforation associated with it. One child sustained bowel injury during the dissection for the liver transplant, but none of the perforations occurred at this site. Bowel function had returned before perforation in five children. Five children were receiving systemic antibiotics at the time of their perforation, and none had been dosed with pulse steroids for rejection. All of the children had significant changes in their temperature. Acute leukopenia developed in one child. A leukocytosis developed in the rest of the children. Abdominal radiographs demonstrated pneumoperitoneum in only one child. All children had positive culture findings from their abdominal drains. Cytomegalovirus developed in one child. Although the diagnosis of gastrointestinal perforation after pediatric liver transplant remains difficult, positive drain culture findings and significant alterations in temperature and leukocyte counts suggest its presence. Pneumoperitoneum is rarely present. Conclusion: A high index of suspicion and timely laparotomy, especially in children less than 2 years of age, may be the only way to rapidly diagnose and treat this potentially devastating complication of liver transplant.

Adenovirus infection in adult orthotopic liver transplant recipients: incidence and clinical significance.

Adenovirus infection occurs in 10% of pediatric orthotopic liver transplant recipients; however, no cases have been described in adult liver transplant recipients. A retrospective review of 191 adults who underwent liver transplantation from January 1988 through October 1995 was done to describe the incidence and clinical significance of adenovirus infection in this population. There were 11 (5.8%) patients with 16 cultures positive for adenovirus. Sites of isolation were urine (9), blood (2), liver biopsy (2), colonic biopsy (1), lung biopsy (1), and stool (1). Adenovirus infection was classified as either disease or asymptomatic infection. There were 7 cases of adenovirus disease (2 definite, 1 probable, and 4 possible). Disease was disseminated in 3 patients: All had pneumonia and 2 died. Of the 3 patients with pneumonia, 2 had evidence of multiorgan involvement. Adenovirus disease occurs in adult orthotopic liver transplant recipients and may be associated with significant morbidity and occasional mortality.

Routine use of the piggyback technique in pediatric orthotopic liver transplantation

The theoretical advantages of the piggyback technique over conventional orthotopic liver transplantation are as follows. (1) Continuous venous decompression during the anhepatic phase is provided without venovenous bypass. (2) Warm ischemia time can be shortened because there is no need for the infrahepatic vena cava anastomosis. The following report is a review of the authors' experience with this method in children during the past year at their institution. Analyses of intraoperative hemodynamics and blood loss, postoperative renal function, patient and graft survival, and length of hospital stay have shown excellent results. There were no intraoperative deaths, and causes of death and graft loss were not related to the technique. The authors conclude that children who undergo liver transplantation can be very satisfactorily managed with the piggyback operation, and this technique may be more advantageous than the conventional method.

Transplantation for end stage liver disease related to alpha 1 antitrypsin.

Alpha 1 antitrypsin deficiency (AT) is an autosomal recessive disease associated with chronic liver disease in adults and children and emphysema in adults. The disease is one of the most common inherited disorders of the Caucasian population of North Europe and North America and is the most common genetic reason for pediatric orthotopic liver transplantation (OLTx), although it is a rare indication in adults. The natural history of the disease is unpredictable and the pathogenesis of the liver injury unclear. Thirty-five patients with histologically apparent alpha 1 AT accumulation in the liver (22 adults, 13 children) have been transplanted in this center. Clinical features were correlated with the pretransplant phenotype, serum alpha 1 antitrypsin levels and potential precipitating factors. All children were PiZZ homozygotes, most of whom had presented with neonatal hepatitis. The majority of adult patients were heterozygotes presenting with portal hypertension and liver cirrhosis. Current one-year posttransplant survival figures are 73% for adults and 87.5% for children. Replacement of the cirrhotic liver results in acquisition of the donor phenotype, a rise in serum levels of alpha 1 antitrypsin, and apparent prevention of associated disease.

Pediatric orthotopic liver transplantation: Potential source of intraoperative blood loss and coagulation status monitoring: S.A. Stayer, R.E. Schwartz, C.A. Pasquariello, et al. Pediatr Surg Int 10:317–321, (July), 1995

Pediatric orthotopic liver transplantation: Potential source of intraoperative blood loss and coagulation status monitoring: S.A. Stayer, R.E. Schwartz, C.A. Pasquariello, et al. Pediatr Surg Int 10:317–321, (July), 1995

Intraoperative blood loss in pediatric liver transplantation: analysis of preoperative risk factors.

The relative contribution of 14 preoperative risk factors to a high intraoperative blood loss was studied in 95 consecutive first pediatric orthotopic liver transplantations (OLT). Patients were distributed in two groups according to red blood cell (RBC) requirements. Wide interindividual RBC requirements were observed (median, 79 mL/kg; range, 4-586). The upper quartile of the population was defined as the high blood loss group and required 123 mL/kg or more (median, 161). On univariate analysis, the high blood loss group had a significantly higher proportion of patients with portal vein hypoplasia, intraabdominal malformations, signs of severe liver failure (encephalopathy, ascites, prolonged prothrombin time), and requiring inpatient support. Age, previous abdominal surgery, and platelet count had no prognostic value. All variables used in the univariate analysis were included in a stepwise logistic regression analysis. Only presence of portal vein hypoplasia, inpatient support, and use of a reduced-size liver graft were independently associated with a high blood loss. Adjusted odds ratios were 40.4 (95% confidence interval; 5.9-278), 5.4 (1.6-17.9), and 3.8 (0.9-15.2), respectively, highlighting the importance of portal vein hypoplasia as a risk factor for high blood loss.

Intraoperative Blood Loss in Pediatric Liver Transplantation

The relative contribution of 14 preoperative risk factors to a high intraoperative blood loss was studied in 95 consecutive first pediatric orthotopic liver transplantations (OLT).Patients were distributed in two groups according to red blood cell (RBC) requirements. Wide interindividual RBC requirements were observed (median, 79 mL/kg; range, 4-586). The upper quartile of the population was defined as the high blood loss group and required 123 mL/kg or more (median, 161). On univariate analysis, the high blood loss group had a significantly higher proportion of patients with portal vein hypoplasia, intraabdominal malformations, signs of severe liver failure (encephalopathy, ascites, prolonged prothrombin time), and requiring inpatient support. Age, previous abdominal surgery, and platelet count had no prognostic value. All variables used in the univariate analysis were included in a stepwise logistic regression analysis. Only presence of portal vein hypoplasia, inpatient support, and use of a reducedsize liver graft were independently associated with a high blood loss. Adjusted odds ratios were 40.4 (95% confidence interval; 5.9-278), 5.4 (1.6-17.9), and 3.8 (0.9-15.2), respectively, highlighting the importance of portal vein hypoplasia as a risk factor for high blood loss. (Anesth Analg 1995;81:1142-7)

Pediatric orthotopic liver transplantation: potential predictors of intraoperative blood loss and coagulation status monitoring

The authors reviewed 14 potential risk factors associated with blood loss in each of 70 liver transplant patients. Although on a statistical basis age correlated as a predictor of intraoperative blood loss, this association was not strong enough to be of clinical value. The authors were unable to predict which patients will have greater intraoperative blood loss. Preparation for massive transfusion should be used for all patients undergoing liver transplantation.

Role of hepatitis C virus in chronic liver disease occurring after orthotopic liver transplantation.

Paediatric orthotopic liver transplant recipients may develop chronic hepatitis after surgery. To investigate the role of hepatitis C virus in this pathology a cohort of 249 paediatric orthotopic liver transplant recipients was studied. Sixteen children (6.4%) were found to have chronic hepatitis C virus hepatitis after orthotopic liver transplantation. All but one of them had serum transaminase values which were persistently raised two to eight times the upper limit of normal. Thirteen were positive for both serology and serum hepatitis C virus RNA. Serum hepatitis C virus RNA detection occurred five to 33 months before hepatitis C virus antibodies. Liver tissue hepatitis C virus RNA and hepatitis C virus core antigen were detected in five. In one patient, tissue hepatitis C virus core antigen was detected when other tests for hepatitis C were negative. Two patients had positive human cytomegalovirus serum antibodies and RNA before transplantation. Although serum hepatitis C virus RNA was not detected after transplantation, serum enzyme immunosorbent assay and tissue core antigen were still detectable in both patients. In another child, serum hepatitis C virus RNA was positive and hepatitis C virus core antigen was found on a liver biopsy specimen but antihepatitis C virus antibodies were negative as well as liver hepatitis C virus RNA. No patient developed severe liver disease or cirrhosis during a follow up of up to 72 months. It is concluded that hepatitis C virus is a significant cause of morbidity after paediatric orthotopic liver transplantation. Diagnosis cannot rely on serological testing only. The patients remained stable on follow up, but longer prospective histological studies remain necessary to establish prognosis.

The Treatment of Intractable Rejection with Tacrolimus (FK506) in Pediatric Liver Transplant Recipients

SummaryWe report our experience in 17 pediatric orthotopic liver transplant (OLT) patients converted from cyclosporine (CsA) to FK506 for intractable acute and chronic rejection. FK506 was initiated orally at a dose of 0.3 mg/kg/day in most patients; the dose was then adjusted to achieve serum levels of 0.5–1.5 ng/ml. Azathio‐prine was discontinued and low‐dose prednisone maintained. The median time between liver transplantation and FK506 conversion was 41 months. Patients have been treated for an average of 14.8 ± 9.6 months. Six patients were converted for acute rejection and 11 for chronic rejection, i.e., vanishing bile duct syndrome (VBDS). After FK506 conversion, the actual patient and graft survival was 88% and 82%, respectively, in the group as a whole. Two patients died, one of chronic active hepatitis C and the other of lymphoma. Three patients, all with VBDS, did not respond to FK506 and therefore required retransplantation. The serum bilirubin is currently normal in 14 patients and the serum transaminases < 100 IU/ml in 12. The mean bilirubin pre‐FK506 of patients successfully converted to FK506 was 4.2 mg/dl compared to 11.8 mg/dl in patients who failed conversion. Major complications included nephrotoxicity, neurotoxicity, and lymphoma. The mean glomerular filtration rate (GFR) of 97 ± 29 mls/min/1.73m2 prior to FK506 conversion dropped to 51 ± 20 mls/min/1.73m2 (p = 0.0001) after a mean of 13.6 months of FK506 therapy. Three patients have developed B‐cell lymphomas; two of them responded to decreased immunosuppression and one died. We conclude that intractable liver graft rejection in children is most successfully reversed if FK506 is instituted before cholestasis becomes pronounced. The high cumulative doses of immunosuppression needed to control intractable rejection places these patients at special risk for developing lymphomas.

The influence of intraoperative blood loss on graft survival and morbidity after orthotopic liver transplantation in children

The aim of this study was to analyze the influence of intraoperative blood loss, expressed as an index of the circulating blood volume (BL), on patient and graft survival and on morbidity after primary orthotopic liver transplantation (OLT) in a series of 40 consequetive children (Mann-Whitney test, Pearson test). The influence on patient survival could not be assessed due to the low mortality. Graft survival and overall morbidity were not affected. Increased BL led only to a higher incidence of postoperative bleeding, with a subsequent higher intervention rate. In the group of children aged 3.75 years or less, significantly higher BL was found compared to the older children. In addition, prolonged intensive care unit stays and ventilator times were observed in this younger age group. The BL thus has limited repercussions on graft survival and morbidity after primary pediatric OLT.

Hypomagnesemia during pediatric orthotopic liver transplantation.

We evaluated the incidence and severity of serum magnesium (Mg) abnormality along with other electrolyte and acid-base disturbances before and during the course of orthotopic liver transplantation (OLT) in pediatric patients. Serum Mg, Na, K, ionized Ca, pH, and blood gas measurements were performed before and hourly during the course of OLT. Hypomagnesemia was frequently observed in children undergoing OLT. Of a total of 30 recipients, 27 (90%) had hypomagnesemia before surgery; the mean serum Mg value at this time was 0.77±0.15 mmol/L. In most of the recipients, the serum Mg value showed a gradual decrease during the course of OLT until magnesium sulfate supplements were administered. On the other hand, the serum Na, K, and ionized Ca levels and acid-base balance were normal before the beginning of surgery. However, hypernatremia, hypokalemia, a decrease in ionized Ca, and metabolic acidosis were commonly observed during the course of OLT. We conclude that electrolyte abnormalities, including hypomagnesemia and metabolic acidosis, commonly develop in children during the course of OLT. The frequent assessment of electrolytes, pH and blood gases is essential for the correction of these abnormalities during the course of OLT.

Hypomagnesemia during pediatric orthotopic liver transplantation

Hypomagnesemia during pediatric orthotopic liver transplantation

Diagnosis and Treatment of Bowel Perforation Following Pediatric Orthotopic Liver Transplantation

Bowel perforation is a frequent cause of mortality after pediatric orthotopic liver transplantation. The aims of this study were to identify the cause of this phenomenon and to examine current methods of treatment. This is a retrospective analysis of 246 pediatric patients who underwent orthotopic liver transplantation at a large, urban, tertiary care medical center between 1984 and 1992. We examined the frequency of bowel perforations after transplantation and identified predisposing factors and signs. In this series, bowel perforations occurred in 24 of 246 recipients and were common in those who had previous liver-related surgery (22 patients). Clinical signs included fever (13 patients), leukocytosis (14 patients), and free air on abdominal roentgenograms (11 patients). Perforation occurred at the Roux-en-Y limb in 15 of 24 recipients as well as in the right transverse colon (five patients), terminal ileum (three patients), and duodenum (one patient). The repair was resection and/or primary closure (18 patients), or diversion (six patients). Recurrent perforations (nine patients) could not be attributed to the method of the repair. Perforation-related sepsis was the primary cause of death in 12 patients (50%) and was more common among patients who developed recurrent perforation (seven [78%] of nine patients). The occurrence and location of bowel perforation after pediatric orthotopic liver transplantation suggests that the cause is related to bowel injury during difficult hepatectomy. Mortality may be reduced by early second-look operations in high-risk patients.

Biliary tract complications in pediatric orthotopic liver transplantation

Biliary tract complications are reported in 15% to 30% of orthotopic liver transplantations (OLTs). Since 1986, 53 OLTs were done in 48 children with a mean age and weight of 5.3 years and 18.9 kg, respectively. Twenty-seven transplantations (51%) were reduced liver grafts (RLG) and 26 (49%) were whole liver grafts (WLG). Since 1988, 70% of transplantations have been RLG. Choledochocholedochostomy (mean weight, 25 kg) with a T-tube (CC) or choledochojejunostomy (CJ) (mean weight, 14.5 kg) were done in 24 (45%) and 29 (55%) cases, respectively. The overall mortality was 19% but none of the deaths were related to biliary problems. There were 13 biliary tract complications (24.5%) in 11 patients including 7 leaks, 5 obstructions, and 1 intrahepatic biloma. Leaks leading to bile peritonitis were managed with simple suture and drainage and were related to the T-tube (4), to the Roux-en-Y loop (2), and to the transection margin of a RLG (1). Obstruction was documented in 5 cases with none associated with hepatic artery thrombosis (HAT). Stenosis after CC reconstruction (2) required conversion to CJ. Two patients had revision of CJ because of kinking of the common bile duct after a left lateral segment graft and an anastomotic stricture 46 months after OLT. The last patient developed a vanishing bile duct syndrome 4 months posttransplant and is awaiting retransplantation. One patient had multiple episodes of cholangitis after HAT and was retransplanted. Neither the type of grafts (RLG 25.9% v WLG 23.1%) nor the type of biliary reconstruction (CC 25% v CJ 24%) influenced the rate of biliary complications. RLG are not associated with an increased risk of biliary leak at the transection margin and the only case in this series improved after correction of a distal anastomotic obstruction. Biliary tract complications can be decreased by meticulous surgical technique and selective use of T-tube drainage during OLT.

SELECTIVE DECONTAMINATION IN PEDIATRIC LIVER TRANSPLANTS

Although it has been suggested that selective decontamination of the digestive tract (SDD) decreases postoperative aerobic Gram-negative and fungal infections in orthotopic liver transplantation (OLT), no controlled trials exist in pediatric patients. This prospective, randomized controlled study of 36 pediatric OLT patients examines the effect of short-term SDD on postoperative infection and digestive tract flora. Patients were randomized into two groups. The control group received perioperative parenteral antibiotics only. The SDD group received in addition polymyxin E, tobramycin, and amphotericin B enterally and by oropharyngeal swab postoperatively until oral intake was tolerated (6 +/- 4 days). Indications for operation, preoperative status, age, and intensive care unit and hospital length of stay were no different in SDD (n = 18) and control (n = 18) groups. A total of 14 Gram-negative infections (intraabdominal abscess 7, septicemia 5, pneumonia 1, urinary tract 1) developed in the 36 patients studied. Mortality was not significantly different in the two groups. However, there were significantly fewer patients with Gram-negative infections in the SDD group: 3/18 patients (11%) vs. 11/18 patients (50%) in the control group, P < 0.001. There was also significant reduction in aerobic Gram-negative flora in the stool and pharynx in patients receiving SDD. Gram-positive and anaerobic organisms were unaffected. We conclude that short-term postoperative SDD significantly reduces Gram-negative infections in pediatric OLT patients.

ARTERIAL KETONE BODY RATIO IN PEDIATRIC LIVER TRANSPLANTATION

Arterial ketone body ratio (AKBR) was measured serially in 49 pediatric orthotopic liver transplantations. The AKBR pattern correlated with hepatic synthetic function, as well as with short-term graft and patient survival. A rapid recovery pattern of AKBR to above 1.0 within 40 hr after reperfusion was associated with 94% graft and patient survival. Pediatric liver grafts were found to have better tolerance to low energy levels when compared with previously published data for adult OLT. The salvage rate of pediatric grafts exhibiting a slow recovery pattern (AKBR 0.7-1.0) was 71%. No recovery pattern (AKBR < 0.7) was seen in all 6 cases of primary nonfunction, and in 3 of 4 cases of early hepatic artery thrombosis (HAT). All these grafts were lost; however, 56% of the children in this group survived retransplantation. Unlike the PNF grafts, the no recovery pattern after HAT was characterized by gradual improvement of the synthetic function, despite the low energy state.

Infectious complications of pediatric liver transplantation

Twenty-five pediatric orthotopic liver transplantations (OLTs) performed in 22 patients at Sainte-Justine Hospital were reviewed for infections complications. One patient died within 12 hours posttransplantation and is excluded. The patients had an average age of 6.1 years (range, 1.25 to 19 years) and an average weight of 20.4 kg (range, 11 to 55 kg). Two patients (9%) were cytomegalovirus (CMV) seropositive and 9 of 19 patients (48%) were Epstein-Barr virus (EBV) seropositive preoperatively. Five of the donors (20%) were CMV seropositive. The most common indications for OLT were biliary atresia (8) and tyrosinemia (7). There were 4 deaths, for an overall mortality rate of 19%. In 3 patients, deaths were related to infection (CMV hepatitis and duodenitis with aortoduodenal fistula, adult respiratory distress syndrome [ARDS] with Streptococcus viridans pneumonia, Escherichia coli cholangitis with progressive hepatic failure). Fifteen patients (72%) had 41 major infections, most of them bacterial, during the first month posttransplantation. These include pneumonia (25%), line sepsis (17%), cholangitis (14%), and tracheitis (14%). There was only one major viral infection, a CMV hepatitis that occurred in the first month posttransplantation. Three patients had fungal infections (8%) associated with hepatic artery thrombosis and recurrent cholangitis. All three patients required retransplantation. There was only one protozoal infection ( Pneumocystis carinii pneumonia) causing life-threatening respiratory failure, from which patient recovered without sequelae. Infection still remains a serious complication of OLT. Bacterial infection is common and is usually associated with technical complications. The low rate of CMV infection is related to low incidence of CMV in the donor pool and the minimal use of strong immunosuppressants.