Postreperfusion syndrome during liver transplantation for cirrhosis: outcome and predictors

A Review of the Risk Factors and Approaches to Prevention of Post-Reperfusion Syndrome During Liver Transplantation

Post-reperfusion syndrome (PRS) is a severe and highly lethal syndrome that occurs after declamping the portal vein forceps during liver transplantation. It is marked by severe hemodynamic disturbances manifested by decreased mean arterial pressure, increased heart rate and elevated pulmonary artery pressure. The complex pathogenesis of PRS remains understudied. It is generally believed to be related to the large amount of acidic, cold blood that enters the circulation after release of the portal clamp. This blood is rich in oxygen-free radicals and metabolic toxins, which not only aggravate the ischemia-reperfusion injury of the liver but also further attack the systemic organs indiscriminately. Considering the range of possible adverse prognoses including acute kidney injury, delirium and graft nonfunction, it is imperative that clinicians increase their awareness and prevention of PRS. The aim of this article is to review the current risk factors, pathophysiological mechanisms and prevention strategies for PRS.

Bridging the critically ill patient with acute to chronic liver failure to liver transplantation

Liver transplantation (LT) has emerged as an effective therapy for severe forms of acute-on-chronic liver failure (ACLF), an entity characterized by the development of multiorgan failure and high short-term mortality. The aim of critical care management of ACLF patients is to rapidly treat precipitating events and aggressively support failing organs to ensure that patients may successfully undergo LT or, less frequently, recover. Malnutrition and sarcopenia are frequently present, adversely impacting the prognosis of these patients. Management of critical care patients with ACLF is complex and requires the participation of different specialties. Once the patient is stabilized, a rapid evaluation for salvage LT should be performed because the time window for LT is often narrow. The development of sepsis and prolonged organ support may preclude LT or diminish its chances of success. The current review describes strategies to bridge severe ACLF patients to LT, highlights the minimal evaluation required for listing and the currently suggested contraindications to proceed with LT, and addresses different aspects of management during the perioperative and early posttransplant period.

Effect of dexmedetomidine on the incidence of postoperative acute kidney injury in living donor liver transplantation recipients: a randomized controlled trial

BACKGROUND

Acute kidney injury (AKI) is one of the most common complications after living-donor liver transplantation (LDLT) that has great impact on recipient and graft outcomes. Dexmedetomidine is reported to decrease the incidence of AKI. In the current study, the authors investigated whether intraoperative dexmedetomidine infusion would reduce the AKI following LDLT.

MATERIAL AND METHODS

In total, 205 adult patients undergoing elective LDLT were randomly assigned to the dexmedetomidine group ( n =103) or the control group ( n =102). Dexmedetomidine group received continuous dexmedetomidine infusion at a rate of 0.4 mcg/kg/h after the anesthesia induction until 2 h after graft reperfusion. The primary outcome was to compare the incidence of AKI. Secondary outcomes included serial lactate levels during surgery, chronic kidney disease, major adverse cardiovascular events, early allograft dysfunction, graft failure, overall mortality, duration of mechanical ventilation, intensive care unit, and hospital length of stay. Intraoperative hemodynamic parameters were also collected.

RESULTS

Of 205 recipients, 42.4% ( n =87) developed AKI. The incidence of AKI was lower in the dexmedetomidine group (35.0%, n =36/103) compared with the control (50.0%, n =51/102) ( P =0.042). There were significantly lower lactate levels in the dexmedetomidine group after reperfusion [4.39 (3.99-4.8) vs 5.02 (4.62-5.42), P =0.031] until the end of surgery [4.23 (3.73-4.74) vs 5.35 (4.84-5.85), P =0.002]. There were no significant differences in the other secondary outcomes besides lactate. Also, intraoperative mean blood pressure, cardiac output, and systemic vascular resistance did not show any difference.

CONCLUSION

Our study suggests that intraoperative dexmedetomidine administration was associated with significantly decreased AKI incidence and lower intraoperative serum lactate levels in LDLT recipients, without untoward hemodynamic effects.

Post Liver Transplant Renal Dysfunction-Evaluation, Management and Immunosuppressive Practice

Liver transplantation (LT) is an effective and lifesaving treatment for patients with end-stage liver disease and hepatocellular carcinoma. Significant improvement in intermediate and long-term survival has been possible due to advancements in immunosuppressive therapy, perioperative care, and surgical techniques. Despite these advances, metabolic complications, including diabetes mellitus, cardiovascular diseases, malignancies, and renal dysfunction, are challenging issues after LT. Acute kidney injury (AKI) and chronic kidney disease (CKD) after LT are common and result in significant morbidity and mortality. Early diagnosis of kidney injury after LT is challenging, and no technique has yet proven effective in prediction of renal dysfunction. The methods for assessing renal function range from formulas that predict glomerular filtration rate to non-invasive biomarkers. The universal adoption of the model for end-stage liver disease has a direct impact on the incidence of peri-transplant AKI and development of CKD in the long-term. Post-LT renal dysfunction is multifactorial and is usually a result of pre-transplantation comorbidities, occurrence of renal dysfunction on the waiting list, perioperative events, and post-transplant nephrotoxic immunosuppressive medication use. Early identification of patients at risk for renal dysfunction and adoption of preventive measures are crucial in the pre-transplant period. No data are currently available to suggest a surgical technique that reliably demonstrates renal protection. Nephroprotective strategies during LT follow accepted surgical practice guidelines, such as maintenance of intravascular volume and mean arterial pressure. The management of kidney disease following LT is challenging, as by the time the serum creatinine is significantly elevated, few interventions impact the course of progression. Early nephroprotective measures are strongly advised and they mostly center on delaying the administration of calcineurin inhibitors (CNIs) during the initial postoperative period, lowering CNI dosage and combining CNI with mycophenolate mofetil and everolimus. The reasons for renal failure following LT, the techniques used to diagnose it, and the therapies designed to preserve renal function both immediately and late after LT are all critically evaluated in this review.

Effects of Extracellular Calcium Concentration on Hepatic Ischemia-Reperfusion Injury in a Rat Model

OBJECTIVES

Hypocalcemia is frequently identified during liver transplant. However, supplementation of extracellular calcium could induce increased intracellular calcium concentration, as a potential factor for injury to the liver graft. We evaluated the effects of regulating extracellular calcium concentrations on hepatic ischemia-reperfusion injury.

MATERIALS AND METHODS

We randomly divided 24 Sprague-Dawley rats into 3 groups: group C received normal saline (n = 8), group L received citrate to induce hypocalcemia (n = 8), and group L-Co received citrate followed by calcium gluconate to ameliorate hypocalcemia (n = 8). Liver enzyme levels and extracellular calcium were measured before surgery, 1 hour after ischemia, and 2 hours after reperfusion. The primary outcome was liver enzyme levels measured 2 hours after reperfusion. In addition, we evaluated intracellular calcium levels, lactate dehydrogenase activity, and histopathological results in liver tissue.

RESULTS

Three groups demonstrated significant differences in extracellular calcium concentrations, but intracellular calcium concentrations in liver tissue were not significantly different. Group L showed significantly lower mean arterial pressure than other groups at 1 hour after ischemia (93.6 ± 20.8 vs 69.4 ± 14.2 vs 86.6 ± 10.4 mmHg; P = .02, for group C vs L vs L-Co, respectively). At 2 hours after reperfusion, group L showed significantly higher liver enzymes than other groups (aspartate aminotransferase 443.0 ± 353.2 vs 952.3 ± 94.8 vs 502.4 ± 327.3 U/L, P = .01; and alanine aminotransferase 407.9 ± 406.5 vs 860.6 ± 210.9 vs 333.9 ± 304.2 U/L, P = .02; for group C vs L vs L-Co, respectively). However, no significant difference was shown in lactate dehydrogenase and histological liver injury grade.

CONCLUSIONS

Administering calcium to rats with hypocalcemia did not increase intracellular calcium accumulation but instead resulted in less hepatic injury compared with rats with low extracellular calcium concentrations in this rat model study.

Use of Transesophageal Echocardiography During Orthotopic Liver Transplantation: Simplifying the Procedure

The intraoperative management of patients undergoing orthotopic liver transplantation (OLT) is influenced by the cardiovascular manifestations typically found in the context of end-stage liver disease, by the presence of concomitant cardiovascular disease, and by the significant hemodynamic changes that occur during surgery. Hypotension and intraoperative blood pressure fluctuations during OLT are associated with liver graft dysfunction, acute kidney failure, and increased risk of 30-d mortality. Patients also frequently present hemodynamic instability due to various causes, including cardiac arrest. Recent evidence has shown transesophageal echocardiography (TEE) to be a useful minimally invasive monitoring tool in patients undergoing OLT that gives valuable real-time information on biventricular function and volume status and can help to detect OLT-specific complications or situations. TEE also facilitates rapid diagnosis of life-threatening conditions in each stage of OLT, which is difficult to identify with other types of monitoring commonly used. Although there is no consensus on the best approach to intraoperative monitoring in these patients, intraoperative TEE is safe and useful and should be recommended during OLT, according to experts, for assessing hemodynamic changes, identifying possible complications, and guiding treatment with fluids and inotropes to achieve optimal patient care.

Postreperfusion Syndrome in Patients Receiving Vasoactive Drugs During Liver Graft Reperfusion

OBJECTIVES

The most widely used definition of postreperfusion syndrome in liver transplant is a 30% decrease in mean arterial pressure during the first 5 minutes after vascular unclamping. With these criteria, increased postoperative morbidity has been reported. Vasoactivedrugs couldpreventthis syndrome.Themain objective of our study was to determine the incidence and complications associated with postreperfusion syndrome inpatientswho receivedvasoactive support.

MATERIALS AND METHODS

We studied 246 patients who received norepinephrine infusions to maintain mean arterial pressure ≥60 mm Hg and who were monitored with a Swan-Ganz catheter. Patients received a bolus of adrenaline after vascular unclamping in cases of insufficient response to norepinephrine.

RESULTS

Among the study patients, 57 (23.17%) developed postreperfusion syndrome. Patients who developed postreperfusion syndrome did not present with morepostoperative complications interms ofrenal dysfunction (P = .69), repeat surgery (P = .15), graft rejection (P = .69), transplant replacement surgery (P = .76), hospital stay (P = .70), or survival (P = .17) compared with patients without postreperfusion syndrome.

CONCLUSIONS

In patients who underwent orthotopic liver transplant, in whom vasoactive drugs were administered, a diagnosis of self-limited postreperfusion syndrome during the first 5 minutes after unclamping may not be associated with postoperative complications. The administration of vasoconstrictors may have a preventive effect on the postoperative complications associated with postreperfusion syndrome or they may mask the real incidence of postreperfusion syndrome. A broader definition of postreperfusion syndrome should be accepted.

Intravenous Ascorbic Acid for the Prevention of Postreperfusion Syndrome in Orthotopic Liver Transplantation: Protocol for a Randomized Controlled Trial

BACKGROUND

Liver transplantation is the last therapeutic option for patients with end-stage liver disease. Postreperfusion syndrome (PRS), defined as a fall in mean arterial pressure of more than 30% within the first 5 minutes after reperfusion of at least 1 minute, can occur in liver transplantation as a deep hemodynamic instability with associated hyperfibrinolysis immediately after reperfusion of the new graft. Its incidence has remained unchanged since it was first described in 1987. PRS is related to ischemia-reperfusion (I/R) injury, whose pathophysiology involves the release of several mediators from both the donor and the recipient. The antioxidant effect of ascorbic acid has been studied in resuscitating patients with septic shock and burns. Even today, there are publications with conflicting results, and there is a need for further studies to confirm or rule out the usefulness of this drug in this group of patients. The addition of ascorbic acid to preservation solutions used in solid organ transplantation is under investigation to harness its antioxidant effect and mitigate I/R injury. Since PRS could be considered a manifestation of I/R injury, we believe that the possible beneficial effect of ascorbic acid on the occurrence of PRS should be investigated.

OBJECTIVE

The aim of this randomized controlled trial is to assess the benefits of ascorbic acid over saline in the development of PRS in adult liver transplantation.

METHODS

We plan to conduct a single-center randomized controlled trial at the Hospital Universitario Ramón y Cajal in Spain. A total of 70 participants aged 18 years or older undergoing liver transplantation will be randomized to receive either ascorbic acid or saline. The primary outcome will be the difference between groups in the incidence of PRS. The randomized controlled trial will be conducted under conditions of respect for fundamental human rights and ethical principles governing biomedical research involving human participants and in accordance with the international recommendations contained in the Declaration of Helsinki and its subsequent revisions.

RESULTS

The enrollment process began in 2020. A total of 35 patients have been recruited so far. Data cleaning and analysis are expected to occur in the first months of 2024. Results are expected around the middle of 2024.

CONCLUSIONS

We believe that this study could be particularly relevant because it will be the first to analyze the clinical effect of ascorbic acid in liver transplantation. Moreover, we believe that this study fills an important gap in the knowledge of the potential benefits of ascorbic acid in the field of liver transplantation, particularly in relation to PRS.

TRIAL REGISTRATION

European Union Drug Regulating Authorities Clinical Trials Database 2020-000123-39; https://tinyurl.com/2cfzddw8; ClinicalTrials.gov NCT05754242; https://tinyurl.com/346vw7sm.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/50091.

Norepinephrine boluses for the prevention of post-reperfusion syndrome in living donor liver transplantation: A prospective, open-label, single-arm feasibility trial

Background and Aims

Post-reperfusion syndrome (PRS) is a serious haemodynamic event during liver transplantation (LT), which increases early graft dysfunction and mortality. This study aimed to test the efficacy and safety of norepinephrine (NE) boluses to prevent PRS during orthotopic LT.

Methods

This feasibility phase II trial prospectively recruited a single arm of 40 patients undergoing living donor LT. The intervention was an escalated protocol of NE boluses starting at 20 µg. The primary outcome was the incidence of PRS. The secondary outcomes were arrhythmia, electrocardiographic (EKG) ischaemic changes, mean pulmonary pressure after reperfusion, 3-month survival and 1-year survival.

Results

PRS occurred in 28 (70%) cases [95% confidence interval (CI) 54% to 83%, P < 0.001], with a relative risk reduction of 0.22 when compared to our previous results (90%). Twelve cases developed transient EKG ischaemic changes. All EKG ischaemic changes returned to baseline after correction of hypotension. There was no significant arrhythmia or bradycardia (95% CI 0 to 0.9). After reperfusion, the mean pulmonary artery pressure was not significantly higher than the normal limit (20 mmHg) (P = 0.88). The 3-month survival was 0.95 (95% CI 0.83 to 0.99), and the 1-year survival was 0.93 (95% CI 0.8 to 0.98).

Conclusion

Our findings suggest that NE boluses starting with 20 μg is feasible and effective in lowering the risk of PRS during living donor LT. Additionally, NE boluses were not associated with significant myocardial ischaemic events, arrhythmia or a rise in pulmonary pressure.

Hepatic ischemia-reperfusion syndrome and its effect on the cardiovascular system: The role of treprostinil, a synthetic prostacyclin analog

Hepatic ischemia-reperfusion syndrome has been the subject of intensive study and experimentation in recent decades since it is responsible for the outcome of several clinical entities, such as major hepatic resections and liver transplantation. In addition to the organ's post reperfusion injury, this syndrome appears to play a central role in the dysfunction of distant tissues and systems. Thus, continuous research should be directed toward finding effective therapeutic options to improve the outcome and reduce the postoperative morbidity and mortality rates. Treprostinil is a synthetic analog of prostaglandin I2, and its experimental administration has shown encouraging results. It has already been approved by the Food and Drug Administration in the United States for pulmonary arterial hypertension and has been used in liver transplantation, where preliminary encouraging results showed its safety and feasibility by using continuous intravenous administration at a dose of 5 ng/kg/min. Treprostinil improves renal and hepatic function, diminishes hepatic oxidative stress and lipid peroxidation, reduces hepatictoll-like receptor 9 and inflammation, inhibits hepatic apoptosis and restores hepatic adenosine triphosphate (ATP) levels and ATP synthases, which is necessary for functional maintenance of mitochondria. Treprostinil exhibits vasodilatory properties and antiplatelet activity and regulates proinflammatory cytokines; therefore, it can potentially minimize ischemia-reperfusion injury. Additionally, it may have beneficial effects on cardiovascular parameters, and much current research interest is concentrated on this compound.

Perioperative clinical practice in liver transplantation: a cross-sectional survey

PURPOSE

The objective of this study was to describe some components of the perioperative practice in liver transplantation as reported by clinicians.

METHODS

We conducted a cross-sectional clinical practice survey using an online instrument containing questions on selected themes related to the perioperative care of liver transplant recipients. We sent email invitations to Canadian anesthesiologists, Canadian surgeons, and French anesthesiologists specialized in liver transplantation. We used five-point Likert-type scales (from "never" to "always") and numerical or categorical answers. Results are presented as medians or proportions.

RESULTS

We obtained answers from 130 participants (estimated response rate of 71% in Canada and 26% in France). Respondents reported rarely using transesophageal echocardiography routinely but often using it for hemodynamic instability, often using an intraoperative goal-directed hemodynamic management strategy, and never using a phlebotomy (medians from ordinal scales). Fifty-nine percent of respondents reported using a restrictive fluid management strategy to manage hemodynamic instability during the dissection phase. Forty-two percent and 15% of respondents reported using viscoelastic tests to guide intraoperative and postoperative transfusions, respectively. Fifty-four percent of respondents reported not pre-emptively treating preoperative coagulations disturbances, and 91% reported treating them intraoperatively only when bleeding was significant. Most respondents (48-64%) did not have an opinion on the maximal graft ischemic times. Forty-seven percent of respondents reported that a piggyback technique was the preferred vena cava anastomosis approach.

CONCLUSION

Different interventions were reported to be used regarding most components of perioperative care in liver transplantation. Our results suggest that significant equipoise exists on the optimal perioperative management of this population.

Risk factors for postreperfusion syndrome during living donor liver transplantation in paediatric patients with biliary atresia: a retrospective analysis

BACKGROUND

Living donor liver transplantation (LT) is the main treatment for paediatric biliary atresia (BA) in Asia. During LT, a series of haemodynamic changes often occur during LT reperfusion, which is called postreperfusion syndrome (PRS), and PRS is related to a prolonged postoperative hospital stay, delayed recovery of graft function and increased mortality. To reduce adverse reactions after paediatric living donor LT (LDLT), our study's objectives were to ascertain the incidence of PRS and analyse possible risk factors for PRS.

METHODS

With the approval of the Ethics Committee of our hospital, the clinical data of 304 paediatric patients who underwent LDLT from January 2020 to December 2021 were analysed retrospectively. According to the presence or absence of PRS, the paediatric patients were divided into the non-PRS group and the PRS group. Independent risk factors of PRS were analysed using logistic regression analysis.

RESULTS

PRS occurred in 132 recipients (43.4%). The peak values of AST (816 (507-1625) vs 678 (449-1107), p=0.016) and ALT (675 (415-1402) vs 545 (389-885), p=0.015) during the first 5 days after LDLT in paediatric patients with PRS were significantly higher than those in the non-PRS group. Meanwhile, the paediatric patients in the PRS group had longer intensive care unit stays and hospital stays, as well as lower 1-year survival rates. Graft cold ischaemic time (CIT) ≥90 min (OR (95% CI)=5.205 (3.094 to 8.754)) and a temperature <36°C immediately before reperfusion (OR (95% CI)=2.973 (1.669 to 5.295)) are independent risk factors for PRS.

CONCLUSIONS

The occurrence of hypothermia (<36.0℃) in children immediately before reperfusion and graft CIT≥90 min are independent risk factors for PRS. PRS was closely related to the postoperative adverse outcomes of paediatric patients.

Prediction, prevention, and treatment of post reperfusion syndrome in adult orthotopic liver transplant patients

IMPORTANCE

This review explores proposed predictors, preventative measures, and treatment options for post-reperfusion syndrome (PRS) in liver transplantation and provides updated data for clinicians.

OBJECTIVES

The review aims to understand the status and progress made regarding PRS during orthotopic liver transplantation. Moreover, the predictors of PRS will be analyzed to highlight risk factors. Mediators of PRS and the modes of action of the currently available preventative and management agents that target particular PRS factors will be investigated.

DATA SOURCES

Data is drawn from secondary sources from databases of peer-reviewed journals. The bibliographies of select sources were also used to obtain additional data studies using the 'snowball' method.

STUDY SELECTION

The initial data search provided 1394 studies analyzed using PRISMA Extension for Scoping Reviews (PRISMA-ScR) guidelines. After applying the eligibility criteria, 18 studies were fit for inclusion.

RESULTS

The study identified that in addition to the severity of underlying medical conditions, other significant PRS predictors included patient age, sex, duration of cold ischemia, and the surgical technique. While the use of epinephrine and norepinephrine is well-established, further preventative measures commonly involve specifically targeting known mediators of the syndrome, such as antioxidants, vasodilators, free radical scavengers, and anticoagulants. Current management strategies involve supportive therapy. Machine Perfusion may ultimately decrease the risk of PRS.

CONCLUSION

PRS still holds unknowns, including the underlying pathophysiology, controllable factors, and ideal management practices. There is a need for further study, particularly prospective trials since liver transplantation is the gold standard for treating end-stage liver disease and the incidence of PRS remains high.

Impact of Hyperoxia after Graft Reperfusion on Lactate Level and Outcomes in Adults Undergoing Orthotopic Liver Transplantation

BACKGROUND

Hyperoxia is common during liver transplantation (LT), without being supported by any guidelines. Recent studies have shown the potential deleterious effect of hyperoxia in similar models of ischemia-reperfusion. Hyperoxia after graft reperfusion during orthotopic LT could increase lactate levels and worsen patient outcomes.

METHODS

We conducted a retrospective and monocentric pilot study. All adult patients who underwent LT from 26 July 2013 to 26 December 2017 were considered for inclusion. Patients were classified into two groups according to oxygen levels before graft reperfusion: the hyperoxic group (PaO₂ > 200 mmHg) and the nonhyperoxic group (PaO₂ < 200 mmHg). The primary endpoint was arterial lactatemia 15 min after graft revascularization. Secondary endpoints included postoperative clinical outcomes and laboratory data.

RESULTS

A total of 222 liver transplant recipients were included. Arterial lactatemia after graft revascularization was significantly higher in the hyperoxic group (6.03 ± 4 mmol/L) than in the nonhyperoxic group (4.81 ± 2 mmol/L), p < 0.01. The postoperative hepatic cytolysis peak, duration of mechanical ventilation and duration of ileus were significantly increased in the hyperoxic group.

CONCLUSIONS

In the hyperoxic group, the arterial lactatemia, the hepatic cytolysis peak, the mechanical ventilation and the postoperative ileus were higher than in the nonhyperoxic group, suggesting that hyperoxia worsens short-term outcomes and could lead to increase ischemia-reperfusion injury after liver transplantation. A multicenter prospective study should be performed to confirm these results.

Evaluation of transcranial Doppler use in patients with acute liver failure listed for emergency liver transplantation

PURPOSE

Acute liver failure (ALF) is characterized by hepatic encephalopathy (HE) often due to intracranial hypertension (ICH). The risk/benefit-balance of intraparenchymal pressure catheter monitoring is controversial during ALF.

AIMS

Perform an evaluation of transcranial Doppler (TCD) use in patients with ALF listed for emergency liver transplantation.

MATERIAL AND METHODS

Single center retrospective cohort study including all patients registered on high emergency LT list between 2012 and 2018. All TCD measurements performed during ICU stay after listing and after LT (when performed) were recorded. TCD was considered abnormal when pulsatility index (PI) was >1.2.

RESULTS

Among 106 patients with ALF, forty-seven (44%) had a TCD while on list. They had more severe liver and extrahepatic organ failure. When performed, TCD was abnormal in 51% of patients. These patients more frequently developed ICH events (45% vs. 13%, p = .02) and more frequently required increase in sedative drugs and vasopressors. While 22% of patients with normal TCD spontaneously survived, all of those with abnormal TCD died or were transplanted (p = .02). All transplanted patients who had abnormal exams normalized their TCD within 2 (1-2) days after LT.

CONCLUSION

TCD may be a useful non-invasive tool for ICH detection and management, then guide sedation withdrawal.

The perioperative period of liver transplantation from unconventional extended criteria donors: data from two high-volume centres

BACKGROUND

As literature largely focuses on long-term outcomes, this study aimed at elucidating the perioperative outcomes of liver transplant patients receiving a graft from two groups of unconventional expanded criteria donors: brain dead aged > 80 years and cardiac dead.

METHODS

Data of 247 cirrhotic patients transplanted at two high volume liver transplant centers were analysed. Confounders were balanced using a stabilized inverse probability therapy weighting and a propensity score for each patient on the original population was generated. The score was created using a multivariate logistic regression model considering a Comprehensive Complication Index ≥ 42 (no versus yes) as the dependent variable and 11 possible clinically relevant confounders as covariate.

RESULTS

Forty-four patients received the graft from a cardiac-dead donor and 203 from a brain-dead donor aged > 80 years. Intraoperatively, cardiac-dead donors liver transplant cases required more fresh frozen plasma units (P < 0.0001) with similar reduced need of fibrinogen to old brain-dead donors cases. The incidence of reperfusion syndrome was similar (P = 0.80). In the Intensive Care Unit, both the groups presented a comparable low need for blood transfusions, renal replacement therapy and inotropes. Cardiac-dead donors liver transplantations required more time to tracheal extubation (P < 0.0001) and scored higher Comprehensive Complication Index (P < 0.0001) however the incidence of a severe complication status (Comprehensive Complication Index  ≥ 42) was similar (P = 0.52). ICU stay (P = 0.97), total hospital stay (P = 0.57), in hospital (P = 1.00) and 6 months (P = 1.00) death were similar.

CONCLUSION

Selected octogenarian and cardiac-dead donors can be used safely for liver transplantation.

Hypothermic Oxygenated Machine Perfusion (HOPE) Prior to Liver Transplantation Mitigates Post-Reperfusion Syndrome and Perioperative Electrolyte Shifts

(1) Background: Post-reperfusion syndrome (PRS) and electrolyte shifts (ES) represent considerable challenges during liver transplantation (LT) being associated with significant morbidity. We aimed to investigate the impact of hypothermic oxygenated machine perfusion (HOPE) on PRS and ES in LT. (2) Methods: In this retrospective study, we compared intraoperative parameters of 100 LTs, with 50 HOPE preconditioned liver grafts and 50 grafts stored in static cold storage (SCS). During reperfusion phase, prospectively registered serum parameters and vasopressor administration were analyzed. (3) Results: Twelve percent of patients developed PRS in the HOPE cohort vs. 42% in the SCS group (p = 0.0013). Total vasopressor demand in the first hour after reperfusion was lower after HOPE pretreatment, with reduced usage of norepinephrine (−26%; p = 0.122) and significant reduction of epinephrine consumption (−52%; p = 0.018). Serum potassium concentration dropped by a mean of 14.1% in transplantations after HOPE, compared to a slight decrease of 1% (p < 0.001) after SCS. The overall incidence of early allograft dysfunction (EAD) was reduced by 44% in the HOPE group (p = 0.04). (4) Conclusions: Pre-transplant graft preconditioning with HOPE results in higher hemodynamic stability during reperfusion and lower incidence of PRS and EAD. HOPE has the potential to mitigate ES by preventing hyperpotassemic complications that need to be addressed in LT with HOPE-pre-treated grafts.

Updates in the Management of Perioperative Vasoplegic Syndrome

Vasoplegic syndrome occurs relatively frequently in cardiac surgery, liver transplant, major noncardiac surgery, in post-return of spontaneous circulation situations, and in pateints with sepsis. It is paramount for the anesthesiologist to understand both the pathophysiology of vasoplegia and the different treatment strategies available for rescuing a patient from life-threatening hypotension.

A brief history of liver transplantation and transplant anesthesia

In this review, we describe the major milestones in the development of organ transplantation with a specific focus on hepatic transplantation. For many years, the barriers preventing successful organ transplantation in humans seemed insurmountable. Although advances in surgical technique provided the technical ability to perform organ transplantation, limited understanding of immunology prevented successful organ transplantation. The breakthrough to success was the result of several significant discoveries between 1950 and 1980 involving improved surgical techniques, the development of effective preservative solutions, and the suppression of cellular immunity to prevent graft rejection. After that, technical innovations and laboratory and clinical research developed rapidly. However, these advances alone could not have led to improved transplant outcomes without parallel advances in anesthesia and critical care. With increasing organ demand, it proved necessary to expand the donor pool, which has been achieved with the use of living donors, split grafts, extended criteria organs, and organs obtained through donation after cardiac death. Given this increased access to organs and organ resources, the number of transplantations performed every year has increased dramatically. New regulatory organizations and transplant societies provide critical oversight to ensure equitable organ distribution and a high standard of care and also perform outcome analyses. Establishing dedicated transplant anesthesia teams results in improved organ transplantation outcomes and provides a foundation for developing new standards for other subspecialties in anesthesiology, critical care, and medicine overall. Through a century of discovery, the success we enjoy at the present time is the result of the work of well-organized multidisciplinary teams following standardized protocols and thereby saving thousands of lives worldwide each year. With continuing innovation, the future is bright.

Postreperfusion Syndrome in Liver Transplant: A Risk Factor for Acute Kidney Failure: A Retrospective Analysis

The maximum expression of hemodynamic instability during liver transplant is the so-called postreperfusion syndrome (PRS) that increases both overall mortality and postoperative complications. It was first defined by Aggarwal et al in 1987, but the results are still conflicting when establishing the relationship between PRS and acute kidney failure (AKF). We conducted a retrospective observational study of transplant recipients with deceased-donor liver grafts between January 2002 and December 2018. We analyzed the incidence of PRS and its potential negative impact over kidney function. A total of 551 transplants were analyzed. PRS was recorded in 130 patients (23.6%). The incidence of AKF was 61.5%. A total of 111 patients required kidney replacement therapy (32.7%). Regarding the severity of AKF, 128 patients were classified as acute kidney injury (AKI) 1 (23.2%), 76 as AKI 2 (13.8%), and 135 as AKI 3 (24.5%). In the group with PRS, 75.4% (n = 98) developed AKF vs 57.2% (n = 241) in the group without PRS. In the multivariate analysis we found a relationship between PRS and AKF with an odds ratio of 2.18 (95% CI, 1.30-3.64; P = .003), once adjusted by the length of the anhepatic phase, donor age, Model for End-Stage Liver Disease score, history of ascites, and need for early surgical reintervention. The incidence of AKF decreased (44.5%) ever since the implementation of delayed calcineurin inhibitors therapy and piggyback surgical technique, but a clear influence of the occurrence of PRS on the development of AKF is still observed, with an OR of 3.78 (95% CI, 1.92-7.43; P < .001), once adjusted by albumin and hemoglobin levels, Model for End-Stage Liver Disease score, and Child classification.

How useful is the machine perfusion in liver transplantation? An answer from a national survey

Machine perfusion (MP) has been shown worldwide to offer many advantages in liver transplantation, but it still has some gray areas. The purpose of the study is to evaluate the donor risk factors of grafts, perfused with any MP, that might predict an ineffective MP setting and those would trigger post-transplant early allograft dysfunction (EAD). Data from donors of all MP-perfused grafts at six liver transplant centers have been analyzed, whether implanted or discarded after perfusion. The first endpoint was the negative events after perfusion (NegE), which is the number of grafts discarded plus those that were implanted but lost after the transplant. A risk factor analysis for NegE was performed and marginal grafts for MP were identified. Finally, the risk of EAD was analyzed, considering only implanted grafts. From 2015 to September 2019, 158 grafts were perfused with MP: 151 grafts were implanted and 7 were discarded after the MP phase because they did not reach viability criteria. Of 151, 15 grafts were lost after transplant, so the NegE group consisted of 22 donors. In univariate analysis, the donor risk index >1.7, the presence of hypertension in the medical history, static cold ischemia time, and the moderate or severe macrovesicular steatosis were the significant factors for NegE. Multivariate analysis confirmed that macrosteatosis >30% was an independent risk factor for NegE (odd ratio 5.643, p = 0.023, 95% confidence interval, 1.27–24.98). Of 151 transplanted patients, 34% experienced EAD and had worse 1- and 3-year-survival, compared with those who did not face EAD (NoEAD), 96% and 96% for EAD vs. 89% and 71% for NoEAD, respectively (p = 0.03). None of the donor/graft characteristics was associated with EAD even if the graft was moderately steatotic or fibrotic or from an aged donor. For the first time, this study shows that macrovesicular steatosis >30% might be a warning factor involved in the risk of graft loss or a cause of graft discard after the MP treatment. On the other hand, the MP seems to be useful in reducing the donor and graft weight in the development of EAD.

Development of a preoperative score to predict surgical difficulty in liver transplantation

BACKGROUND

A difficulty score to predict intraoperative surgical complexity in liver transplantation has never been developed. The aim of this study was to assess factors associated with a difficult liver transplant and develop a score to predict difficult surgery.

METHODS

All patients undergoing deceased donor whole liver transplantation from 2012 to 2019 at a single center were included. Estimated intraoperative blood loss (mL/kg) and surgery duration (skin-to-arterial reperfusion time) were used as surrogates of difficulty. Based on these variables, the study population was divided into 2 groups: high risk and standard risk of difficulty. Univariate and multivariate analyses were performed to identify predictors associated with a demanding liver transplantation and develop a difficulty score.

RESULTS

A total of 515 patients were included in the study population, and 101 (20%) were considered difficult operations. Patients with a higher risk of difficulty showed a significantly higher rate of Clavien-Dindo ≥III complications (50.5% vs 24.4%, P = .001) and a longer hospital stay (19 vs 16 days, P = .001). Preoperative factors associated with difficulty were retransplantation (odds ratio 4.34, P = .001), preoperative portal vein thrombosis (odds ratio 3.419, P = .001), previous upper abdominal surgery (odds ratio 2.161, P = .003), spontaneous bacterial peritonitis (odds ratio 1.985, P < .02), and prior variceal bleeding (odds ratio 1.401, P = .051). A 10-point difficulty score was created, showing a negative predictive value of 84% at 4 points.

CONCLUSION

Difficult liver transplantation surgery, as assessed by skin-to-arterial reperfusion time and estimated blood loss, is associated with worse perioperative outcomes. We developed a simple score with clinical preoperative variables that predicts difficult surgery, and therefore, it may help to optimize allocation policies and perioperative logistics.

Influence of anesthesia type on post-reperfusion syndrome during liver transplantation: a single-center retrospective study

Background

Post-reperfusion syndrome (PRS) results in sudden hemodynamic instability following graft reperfusion. Although PRS is known to influence outcomes following liver transplantation, little is known regarding the effects of anesthetics on PRS. This study investigated the association between the type of anesthetic agent and PRS in liver transplantation.

Methods

This single-center retrospective cohort study included patients who underwent liver transplantation between June 2016 and December 2019. Patients were divided into sevoflurane and propofol groups according to the anesthetic agent used. Stabilized inverse probability of treatment weighting (IPTW) analysis was performed to investigate the association between PRS identified based on blood pressure recordings and the type of anesthesia. Associations between the anesthetic agent and the duration of hypotension as well as early postoperative outcomes were also investigated.

Results

Data were analyzed for 398 patients, 304 (76.4%) and 94 (23.6%) of whom were anesthetized with propofol and sevoflurane, respectively. PRS developed in 40.7% of the 398 patients. Following stabilized IPTW analysis, the association with PRS was lower in the sevoflurane group than in the propofol group (odds ratio, 0.47; P = 0.018). However, there was no association between the type of anesthetic used and early postoperative outcomes.

Conclusions

The association of PRS was lower in the sevoflurane group than in the propofol group. However, there was no association between the type of anesthetic and the early postoperative outcomes. Further studies are required to determine the optimal anesthetic for liver transplantation.

Prognostic Impact of Early Recovering Acute Kidney Injury Following Liver Transplantation: A Multicenter Retrospective Study

BACKGROUND

Acute kidney injury (AKI) is a common complication after liver transplantation (LT), but the specific impact of rapidly resolving AKI is not elucidated. This study investigates the factors associated with early recovery from AKI and its association with post-LT outcomes.

METHODS

Retrospective analysis of 441 liver transplant recipients with end-stage liver disease without pretransplant renal impairment. AKI was defined according to Kidney Disease Improving Global Outcomes criteria and early renal recovery by its disappearance within 7 d post-LT.

RESULTS

One hundred forty-six patients (32%) developed a post-LT AKI, of whom 99 (69%) recovered early and 45 (31%) did not. Factors associated with early recovery were Kidney Disease Improving Global Outcomes stage 1 (odds ratio [OR],14.11; 95% confidence interval [CI], 5.59-40.22; P < 0.0001), minimum prothrombin time >50 % (OR, 4.50; 95% CI, 1.67-13.46; P = 0.003) and aspartate aminotransferase peak value <1000 U/L (OR, 4.07; 95% CI, 1.64-10.75; P = 0.002) within 48 h post-LT. Patients with early recovery had a renal prognosis similar to that of patients without AKI with no difference in estimated glomerular filtration rate between day 7 and 1 y. Their relative risk of developing chronic kidney disease was 0.88 (95% CI, 0.55-1.41; P = 0.6) with survival identical to patients without AKI and better than patients without early recovery (P < 0.0001).

CONCLUSIONS

Most patients with post-LT AKI recover early and have a similar renal prognosis and survival to those without post-LT AKI. Factors associated with early renal recovery are related to the stage of AKI, the extent of liver injury, and the early graft function. Patients at risk of not recovering may benefit the most from perioperative protective strategies, particularly those aimed at minimizing the adverse effects of calcineurin inhibitors.

[Kidney failure after liver transplantation]

One third of cirrhotic patients present impaired kidney function. It has multifactorial causes and has a harmful effect on patients' morbi-mortality before and after liver transplant. Kidney function does not improve in all patients after liver transplantation and liver-transplant recipients are at high risk of developing chronic kidney disease. Causes for renal dysfunction can be divided in three groups: preoperative, peroperative and postoperative factors. To date, there is no consensus for the modality of evaluation the risk for chronic kidney disease after liver transplantation, and for its prevention. In the present review, we describe the outcome of kidney function after liver transplantation, and the prognostic factors of chronic kidney disease to determine a risk stratification for each patient. Furthermore, we discuss therapeutic options to prevent kidney dysfunction in this setting, and highlight the indications of combined liver-kidney transplantation.

Factors Associated With Postreperfusion Syndrome in Living Donor Liver Transplantation: A Retrospective Study

BACKGROUND

Postreperfusion syndrome (PRS) after portal vein reperfusion during liver transplantation (LT) has been reported to cause rapid hemodynamic changes and is associated with a prolonged postoperative hospital stay, renal failure, and increased mortality. Although there are some reports on risk factors for PRS in brain-dead donor LT, there are a few reports on those in living donor LT. Therefore, we retrospectively reviewed the factors associated with PRS to contribute to the anesthetic management so as to reduce PRS during living donor LT.

METHODS

After approval by the ethics committee of our institution, 250 patients aged ≥20 years who underwent living donor LT at our institution between January 2013 and September 2018 were included in the study. A decrease in mean arterial pressure of ≥30% within 5 minutes after portal vein reperfusion was defined as PRS, and estimates and odds ratio (OR) for PRS were calculated using logistic regression. The backward method was used for variable selection in the multivariable analysis.

RESULTS

Serum calcium ion concentration before reperfusion (per 0.1 mmol/L increase; OR, 0.74; 95% confidence interval (CI), 0.60-0.95; P < .001), preoperative echocardiographic left ventricular end-diastolic diameter (per 1-mm increase: OR, 0.90; 95% CI, 0.85-0.95; P < .001, men [versus women: OR, 2.45; 95% CI, 1.26-4.75; P = .008]), mean pulmonary artery pressure before reperfusion (restricted cubic spline, P = .003), anhepatic period (restricted cubic spline, P = .02), and graft volume to standard liver volume ratio (restricted cubic spline, P = .03) were significantly associated with PRS.

CONCLUSIONS

In living donor LT, male sex and presence of small left ventricular end-diastolic diameter, large graft volume, and long anhepatic period are associated with PRS, and a high calcium ion concentration and low pulmonary artery pressure before reperfusion are negatively associated with PRS.

The Requirement of Isoflurane and Remifentanil During Liver Transplantation Using Bispectral Index and Surgical Pleth Index: An Observational Study

BACKGROUND

During liver transplantation (LT), patients and surgical factors potentially influence the pharmacokinetics of the anesthetic agents. The aim of this study was to investigate the requirement of isoflurane and remifentanil according to severity of liver disease during LT under balanced anesthesia.

METHODS

We enrolled 44 patients undergoing LT. Anesthetic depth was maintained within the bispectral index score of 40 to 60 and Surgical Pleth Index of 20 to 60. Patients were divided into 2 groups according to their median Model for End-Stage Liver Disease (MELD) score: low MELD group and high MELD group. We compared end-tidal inhaled anesthetics and remifentanil consumption.

RESULTS

Patients were divided into 2 groups according to median value of MELD score: MELD score <16 (low MELD group; n = 20) or MELD ≥16 (high MELD group; n = 20). There was no significant difference between the 2 groups in end-tidal concentration of isoflurane during 3 phases. However, the remifentanil requirement was lower in the high MELD group during the dissection and anhepatic phases (mean (SD), 0.105 (0.067) vs 0.064 (0.055) µg/kg/min; P = .037, and 0.167 (0.096) vs 0.108 (0.079) µg/kg/min; P = .039, respectively; low MELD group vs high MELD group) with no significant difference during the neohepatic phase.

CONCLUSIONS

The severity of liver dysfunction based on MELD score affected the intraoperative remifentanil requirement during LT. Patients with cirrhosis are required to use analgesics appropriate to their individual patient characteristics in clinical practice.

Postreperfusion syndrome in liver transplantation: Outcomes, predictors, and application for recipient selection

BACKGROUND

This study aimed to identify risk factors for postreperfusion syndrome (PRS) and its impact on LT outcomes.

METHODS

Data analysis was performed in 1021 adult patients undergoing donation after brain death (DBD) LT to identify PRS incidence, the risk factors for PRS development, and its impact on LT outcomes.

RESULTS

The overall incidence of PRS was 16.1%. Independent risk factors for PRS included donor age (odds ratio (OR) 1.01, p = 0.02), donor body mass index (BMI) (OR 1.04, p = 0.003), moderate macrosteatosis (OR 2.48, p = 0.02), and cold ischemia time (CIT) (OR 1.06, p = 0.02). On multivariable analysis for 30-day graft failure, PRS (hazard ratio (HR) 3.49; p<0.001) and Model for End-stage Liver Disease (MELD) score (HR 1.01; p = 0.05) were independent risk factors. Patients were categorized into 4 distinct groups based on PRS risk groups and MELD groups, which showed different 1-year graft survival (p<0.001). There were comparable outcomes between low PRS risk - high MELD and high PRS risk - low MELD group (p = 0.33).

CONCLUSIONS

donor age, donor BMI, moderate macrosteatosis, and CIT were identified as risk factors for the development of PRS in LT using DBD grafts. PRS risk evaluation may improve donor-to-recipient matching based on their MELD scores. This article is protected by copyright. All rights reserved.

Impact of the Share 35 Policy on Perioperative Management and Mortality in Liver Transplantation Recipients

Background

The Share 35 policy was introduced in 2013 by the Organ Procurement and Transplantation Network (OPTN) to increase opportunities of sicker patients to access liver transplantation. However, it has the disadvantage of higher MELD score associated with adverse postoperative transplant outcomes. Early data after implementation of the Share 35 policy showed significantly poorer post-transplantation survival in some UNOS regions. We aimed to analyze the impact of Share 35 on demographics of patients, perioperative management, and perioperative mortality.

Material/Methods

A retrospective analysis of data was performed from an institutional liver transplantation cohort from 1 January 2008 to 31 December 2017. Adult patients who underwent liver transplantation before 2013 were defined as the pre-Share 35 group and the other group was defined as the post-Share 35 group. The MELD score of each patient was calculated at the time of transplantation. Perioperative mortality was defined as death within 30 days after the operation.

Results

A total of 1596 patients underwent liver transplantation. Of those, 895 recipients underwent OLT in the pre-Share 35 era and 737 in the post-Share 35 era. The median MELD score was significantly higher in the post-Share 35 group (30 vs 26, P<0.001) and 45.7% of the post-Share 35 group had MELD scores ≥35. In intraoperative management, patients required significantly more blood component transfusion, intraoperative vasopressor, and fluid replacement. Veno-venous bypass (VVB) usage was significantly higher in the post-Share 35 era (47.2% vs 38.1%, P<0.001). In the subgroup of patients with MELD scores ≥35, the median waiting time was significantly shorter (18.5 vs 14.5 days, P=0.045). Overall perioperative mortality was not significantly difference between groups (P=0.435).

Conclusions

After implementation of the Share 35 policy, we performed liver transplantation in significantly higher medical acuity patients, which required more medical resources to obtain a result comparable to that of the pre-Share 35 era.

Hemodynamic Instability During Liver Transplantation in Patients With End-stage Liver Disease: A Consensus Document from ILTS, LICAGE, and SATA

Hemodynamic instability (HDI) during liver transplantation (LT) can be difficult to manage and increases postoperative morbidity and mortality. In addition to surgical causes of HDI, patient- and graft-related factors are also important. Nitric oxide-mediated vasodilatation is a common denominator associated with end-stage liver disease related to HDI. Despite intense investigation, optimal management strategies remain elusive. In this consensus article, experts from the International Liver Transplantation Society, the Liver Intensive Care Group of Europe, and the Society for the Advancement of Transplant Anesthesia performed a rigorous review of the most current literature regarding the epidemiology, causes, and management of HDI during LT. Special attention has been paid to unique LT-associated conditions including the causes and management of vasoplegic syndrome, cardiomyopathies, LT-related arrhythmias, right and left ventricular dysfunction, and the specifics of medical and fluid management in end-stage liver disease as well as problems specifically related to portal circulation. When possible, management recommendations are made.

Kidney Failure after Liver Transplantation

One-third of patients with cirrhosis present kidney failure (AKI and CKD). It has multifactorial causes and a harmful effect on morbidity and mortality before and after liver transplantation. Kidney function does not improve in all patients after liver transplantation, and liver transplant recipients are at a high risk of developing chronic kidney disease. The causes of renal dysfunction can be divided into three groups: pre-operative, perioperative and post-operative factors. To date, there is no consensus on the modality to evaluate the risk of chronic kidney disease after liver transplantation, or for its prevention. In this narrative review, we describe the outcome of kidney function after liver transplantation, and the prognostic factors of chronic kidney disease in order to establish a risk categorization for each patient. Furthermore, we discuss therapeutic options to prevent kidney dysfunction in this context, and highlight the indications of combined liver–kidney transplantation.

Correlation of Deceased Donor Factors to Postreperfusion Severe Hyperglycemia in Adult Patients Undergoing Liver Transplant

OBJECTIVES

In this study, our objective was to identify perioperative factors associated with postreperfusion severe hyperglycemia, with a particular focus on deceased donor factors.

MATERIALS AND METHODS

Perioperative data from 100 patients without diabetes who were undergoing liver transplant from deceased donors were reviewed. Mean blood glucose levels were calculated at each liver transplant surgical phase, with a cutoff level of 12.7 mmol/L (230 mg/dL) during the neo-hepatic phase defined as postreperfusion severe hyperglycemia. Patients were divided into those with and without postreperfusion severe hyperglycemia. Selected perioperative variables were compared between the 2 groups.

RESULTS

Of 100 patients, 55 developed postreperfusion severe hyperglycemia. Among donor variables, a statistically significant difference between groups was only shown for graft-to-recipient liver weight ratio (P < .001). With regard to preoperative recipient variables, the 2 groups showed a significant difference in mean age (P = .001). Patients in the postreperfusion severe hyperglycemia group required significantly more packed red blood cell transfusions (P = .002), sodium bicarbonate (P = .054), and vasopressors (P = .002) during the operation. Moreover, in terms of laboratory findings, although the last arterial pH was acceptable in both groups, a last lower arterial pH was observed in patients with postreperfusion severe hyperglycemia (P = .011). Higher mean blood glucose levels were detected in the postre - perfusion hyperglycemia group during the preanhepatic and anhepatic phases (P = .024, P = .001, respectively).

CONCLUSIONS

In patients undergoing liver transplant, incidence of postreperfusion severe hyperglycemia was influenced by graft-to-recipient liver weight ratio. Furthermore, postreperfusion severe hyperglycemia was associated with intraoperative clinical and laboratory disturbances in liver transplant recipients.

Association between intraoperative fluid balance, vasopressors and graft complications in liver transplantation: A cohort study

Introduction

Biliary complications following liver transplantation are common. The effect of intraoperative fluid balance and vasopressors on these complications is unknown.

Materials and methods

We conducted a cohort study between July 2008 and December 2017. Our exposure variables were the total intraoperative fluid balance and the use of vasopressors on ICU admission. Our primary outcome was any biliary complication (anastomotic and non-anastomotic strictures) up to one year after transplantation. Our secondary outcomes were vascular complications, primary graft non-function and survival.

Results

We included 562 consecutive liver transplantations. 192 (34%) transplants had a biliary complication, 167 (30%) had an anastomotic stricture and 56 had a non-anastomotic stricture (10%). We did not observe any effect of intraoperative fluid balance or vasopressor on biliary complications (HR = 0.97; 95% CI, 0.93 to 1.02). A higher intraoperative fluid balance was associated with an increased risk of primary graft non-function (non-linear) and a lower survival (HR = 1.40, 95% CI, 1.14 to 1.71) in multivariable analyses.

Conclusion

Intraoperative fluid balance and vasopressors upon ICU admission were not associated with biliary complications after liver transplantation but may be associated with other adverse events. Intraoperative hemodynamic management must be prospectively studied to further assess their impact on liver recipients’ outcomes.

Perioperative ABO Blood Group Isoagglutinin Titer and the Risk of Acute Kidney Injury after ABO-Incompatible Living Donor Liver Transplantation

For ABO-incompatible liver transplantation (ABO-i LT), therapeutic plasma exchange (TPE) is performed preoperatively to reduce the isoagglutinin titer of anti-ABO blood type antibodies. We evaluated whether perioperative high isoagglutinin titer is associated with postoperative risk of acute kidney injury (AKI). In 130 cases of ABO-i LT, we collected immunoglobulin (Ig) G and Ig M isoagglutinin titers of baseline, pre-LT, and postoperative peak values. These values were compared between the patients with and without postoperative AKI. Multivariable logistic regression analysis was used to evaluate the association between perioperative isoagglutinin titers and postoperative AKI. Clinical and graft-related outcomes were compared between high and low baseline and postoperative peak isoagglutinin groups. The incidence of AKI was 42.3%. Preoperative baseline and postoperative peak isoagglutinin titers of both Ig M and Ig G were significantly higher in the patients with AKI than those without AKI. Multivariable logistic regression analysis showed that preoperative baseline and postoperative peak Ig M isoagglutinin titers were significantly associated with the risk of AKI (baseline: odds ratio 1.06, 95% confidence interval 1.02 to 1.09; postoperative peak: odds ratio 1.08, 95% confidence interval 1.04 to 1.13). Cubic spline function curves show a positive relationship between the baseline and postoperative peak isoagglutinin titers and the risk of AKI. Clinical outcomes other than AKI were not significantly different according to the baseline and postoperative peak isoagglutinin titers. Preoperative high initial and postoperative peak Ig M isoagglutinin titers were significantly associated with the development of AKI. As the causal relationship between high isoagglutinin titers and risk of AKI is unclear, the high baseline and postoperative isoagglutinin titers could be used simply as a warning sign for the risk of AKI after liver transplantation.

Hypothermic Oxygenated Perfusion Improves Extended Criteria Donor Liver Graft Function and Reduces Duration of Hospitalization Without Extra Cost: The PERPHO Study

Few studies have evaluated the efficacy or the cost of hypothermic oxygenated perfusion (HOPE) in the conservation of extended criteria donor (ECD) grafts from donation after brain death (DBD) donors during liver transplantation (LT). We performed a prospective, monocentric study (NCT03376074) designed to evaluate the interest of HOPE for ECD-DBD grafts. For comparison, a control group was selected after propensity score matching among patients who received transplants between 2010 and 2017. Between February and November 2018, the HOPE procedure was used in 25 LTs. Immediately after LT, the median aspartate aminotransferase (AST) level was significantly lower in the HOPE group (724UI versus 1284UI; P = 0.046) as were the alanine aminotransferase (ALT; 392UI versus 720UI; P = 0.01), lactate (2.2 versus 2.7; P = 0.01) There was a significant reduction in intensive care unit stay (3 versus 5 days; P = 0.01) and hospitalization (15 versus 20 days; P = 0.01). The incidence of early allograft dysfunction (EAD; 28% versus 42%; P = 0.22) was similar . A level of AST or ALT in perfusate >800UI was found to be highly predictive of EAD occurrence (areas under the curve, 0.92 and 0.91, respectively). The 12-month graft (88% versus 89.5%; P = 1.00) and patient survival rates (91% versus 91.3%; P = 1.00) were similar. The additional cost of HOPE was estimated at € 5298 per patient. The difference between costs and revenues, from the hospital's perspective, was not different between the HOPE and control groups (respectively, € 3023 versus € 4059]; IC, -€ 5470 and € 8652). HOPE may improve ECD graft function and reduce hospitalization stay without extra cost. These results must be confirmed in a randomized trial.

Intraoperative Cardiac Arrest During Adult Liver Transplantation: Incidence and Risk Factor Analysis From 7 Academic Centers in the United States

BACKGROUND

Intraoperative cardiac arrest (ICA) has a reported frequency of 1 in 10,000 anesthetics but has a much higher estimated incidence in orthotopic liver transplantation (OLT). Single-center studies of ICA in OLT are limited by small sample size that prohibits multivariable regression analysis of risks.

METHODS

Utilizing data from 7 academic medical centers, we performed a retrospective, observational study of 5296 adult liver transplant recipients (18-80 years old) between 2000 and 2017 to identify the rate of ICA, associated risk factors, and outcomes.

RESULTS

ICA occurred in 196 cases (3.7% 95% confidence interval [CI], 3.2-4.2) and mortality occurred in 62 patients (1.2%). The intraoperative mortality rate was 31.6% in patients who experienced ICA. In a multivariable generalized linear mixed model, ICA was associated with body mass index (BMI) <20 (odds ratio [OR]: 2.04, 95% CI, 1.05-3.98; P = .0386), BMI ≥40 (2.16 [1.12-4.19]; P = .022), Model for End-Stage Liver Disease (MELD) score: (MELD 30-39: 1.75 [1.09-2.79], P = .02; MELD ≥40: 2.73 [1.53-4.85], P = .001), postreperfusion syndrome (PRS) (3.83 [2.75-5.34], P < .001), living donors (2.13 [1.16-3.89], P = .014), and reoperation (1.87 [1.13-3.11], P = .015). Overall 30-day and 1-year mortality were 4.18% and 11.0%, respectively. After ICA, 30-day and 1-year mortality were 43.9% and 52%, respectively, compared to 2.6% and 9.3% without ICA.

CONCLUSIONS

We established a 3.7% incidence of ICA and a 1.2% incidence of intraoperative mortality in liver transplantation and confirmed previously identified risk factors for ICA including BMI, MELD score, PRS, and reoperation and identified new risk factors including living donor and length of surgery in this multicenter retrospective cohort. ICA, while rare, is associated with high intraoperative mortality, and future research must focus on therapy to reduce the incidence of ICA.

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.

Effects of Intraoperative Fluid Balance During Liver Transplantation on Postoperative Acute Kidney Injury: An Observational Cohort Study

BACKGROUND

Liver transplant recipients suffer many postoperative complications. Few studies evaluated the effects of fluid management on these complications. We conducted an observational cohort study to evaluate the association between intraoperative fluid balance and postoperative acute kidney injury (AKI) and other postoperative complications.

METHODS

We included consecutive adult liver transplant recipients who had their surgery between July 2008 and December 2017. Our exposure was intraoperative fluid balance, and our primary outcome was the grade of AKI at 48 hours after surgery. Our secondary outcomes were the grade of AKI at 7 days, the need for postoperative renal replacement therapy, postoperative red blood cell transfusions, time to first extubation, time to discharge from the intensive care unit (ICU), and 1-year survival. Every analysis was adjusted for potential confounders.

RESULTS

We included 532 transplantations in 492 patients. We observed no effect of fluid balance on either 48-hour AKI, 7-day AKI, or on the need for postoperative renal replacement therapy after adjustments for confounders. A higher fluid balance increased the time to ICU discharge, and increased the risk of dying (hazard ratio = 1.21 [1.04,1.40]).

CONCLUSIONS

We observed no association between intraoperative fluid balance and postoperative AKI. Fluid balance was associated with longer time to ICU discharge and lower survival. This study provides insight that might inform the design of a clinical trial on fluid management strategies in this population.

Effects of intraoperative hemodynamic management on postoperative acute kidney injury in liver transplantation: An observational cohort study

Background

Intraoperative restrictive fluid management strategies might improve postoperative outcomes in liver transplantation. Effects of vasopressors within any hemodynamic management strategy are unclear.

Methods

We conducted an observational cohort study on adult liver transplant recipients between July 2008 and December 2017. We measured the effect of vasopressors infused at admission in the intensive care unit (ICU) and total intraoperative fluid balance. Our primary outcome was 48-hour acute kidney injury (AKI) and our secondary outcomes were 7-day AKI, need for postoperative renal replacement therapy (RRT), time to extubation in the ICU, time to ICU discharge and survival up to 1 year. We fitted models adjusted for confounders using generalized estimating equations or survival models using robust standard errors. We reported results with 95% confidence intervals.

Results

We included 532 patients. Vasopressors use was not associated with 48-hour or 7-day AKI but modified the effects of fluid balance on RRT and mortality. A higher fluid balance was associated with a higher need for RRT (OR = 1.52 [1.15, 2.01], p<0.001 for interaction) and lower survival (HR = 1.71 [1.26, 2.34], p<0.01 for interaction) only among patients without vasopressors. In patients with vasopressors, higher doses of vasopressors were associated with a higher mortality (HR = 1.29 [1.13, 1.49] per 10 μg/min of norepinephrine).

Conclusion

The presence of any vasopressor at the end of surgery was not associated with AKI or RRT. The use of vasopressors might modify the harmful association between fluid balance and other postoperative outcomes. The liberal use of vasopressors to implement a restrictive fluid management strategy deserves further investigation.

Association of post-reperfusion syndrome and ischemia-reperfusion injury with acute kidney injury after liver transplantation

BACKGROUND

Acute kidney injury (AKI) is frequently observed after orthotopic liver transplantation (OLT) even in patients with previously normal renal function. In this study, we investigated the impact of factors such graft steatosis, post-reperfusion syndrome (PRS), and hepatic ischemia reperfusion injury (HIRI) on the development of AKI after OLT in adult patients.

METHODS

We retrospectively examined consecutive adult patients who underwent OLT at our institution between July 2011 and June 2017. AKI was diagnosed based on the criteria proposed by the International Kidney Disease Improving Global Outcomes (KDIGO) workgroup. Peak aspartate aminotransferase (AST) level within 72 hours after OLT was used as a surrogate marker for HIRI. Graft steatosis was diagnosed by histopathological examination using specimens biopsied intraoperatively at the end of transplantation procedure and categorized as <10%, 10%-20%, 20%-30%, and ≥30% of hepatic steatosis.

RESULTS

Out of 386 patients, 141 (37%) developed AKI (KDIGO stage 1:71 patients; stage 2:29 patients; stage 3:41 patients). Multivariable logistic regression analysis revealed that cold ischemic time (P = .012) and HIRI (P = .007) were independent risk factors for post-OLT AKI. Multivariable analysis also revealed that graft steatosis was associated with HIRI but not directly with AKI. PRS was not associated with HIRI or AKI in the multivariable analyses.

CONCLUSION

Our results indicate that greater severity of liver graft injury during transplantation negatively affects renal function after OLT. As expected, the severity of liver graft steatosis contributes to accelerated liver injury occurring during the transplantation procedure.

Intraoperative Hemodynamic Parameters and Acute Kidney Injury After Living Donor Liver Transplantation

BACKGROUND

Acute kidney injury (AKI) after living donor liver transplantation (LDLT) is associated with increased mortality. We sought to identify associations between intraoperative hemodynamic variables and postoperative AKI.

METHODS

We retrospectively reviewed 734 cases of LDLT. Intraoperative hemodynamic variables of systemic and pulmonary arterial pressure, central venous pressure (CVP), and pulmonary artery catheter-derived parameters including mixed venous oxygen saturation (SvO2), right ventricular end-diastolic volume (RVEDV), stroke volume, systemic vascular resistance, right ventricular ejection fraction, and stroke work index were collected. Propensity score matching analysis was performed between patients with (n = 265) and without (n = 265) postoperative AKI. Hemodynamic variables were compared between patients with AKI, defined by Kidney Disease Improving Global Outcomes criteria, and those without AKI in the matched sample.

RESULTS

The incidence of AKI was 36.1% (265/734). Baseline CVP, baseline RVEDV, and SvO2 at 5 minutes before reperfusion were significantly different between patients with and without AKI in the matched sample of 265 pairs. Multivariable logistic regression analysis revealed that baseline CVP, baseline RVEDV, and SvO2 at 5 minutes before reperfusion were independent predictors of AKI (CVP per 5 cm H2O increase: odds ratio [OR], 1.20; 95% confidence interval [CI], 1.09-1.32; SvO2: OR, 1.45; 95% CI, 1.27-1.71; RVEDV: OR, 1.48; 95% CI, 1.24-1.78).

CONCLUSIONS

The elevated baseline CVP, elevated baseline RVEDV after anesthesia induction, and decreased SvO2 during anhepatic phase were associated with postoperative AKI. Prospective trials are required to evaluate whether the optimization of these variables may decrease the risk of AKI after LDLT.

Utilization of Vicryl Bridging Mesh in Orthotopic Liver Transplantation to Achieve Tension-Free Abdominal Wall Closure: A Case Series

Difficulty in primary fascial closure of the abdomen in transplant patients is a common challenge. Abdominal wall tension may have detrimental effects on the newly transplanted graft due to compression, and blood flow hindrance, potentially leading to ischemia or thrombosis and possibly graft failure. Furthermore, patients will be at risk of developing fascial ischemia and dehiscence. Myocutaneous flaps, temporary closure with silastic mesh, abdominal wall transplants, and even graft reduction, bowel resection, and splenectomies have been practiced with varying degrees of success. In this study, we present four cases of patients who underwent orthotopic liver transplantation (OLT) with bridging Vicryl knitted mesh (ETHICON VKML VICRYL-Polyglactin 910-30 × 30 cm) to relieve the tension during the closure. Our results show that these patients, despite having a high average Model End-Stage Liver Disease (MELD) score of 25, had a good liver function at the time of discharge and continue to upon follow-up. They had a relatively short length of stay (LOS) in both the intensive care unit (ICU) and in the hospital, an average of 3.5 days and 9 days, respectively. Our case series successfully show that utilizing a bridging Vicryl knitted mesh is a reasonable approach to attain tension-free abdominal closure in OLT with satisfying results.

Protective Role of the Portocaval Shunt in Liver Transplantation

BACKGROUND

Advances in medical management and surgical technique have resulted in stepwise improvements in early post-transplant survival rates. Modifications in the surgical technique, such as the realization of the portocaval shunt (PCS), could influence survival rates. The aim of this study was to evaluate the mortality rate for 12 months after liver transplantation, analyzing the causes and risk factors related to its development and assessing the impact that PCS could have on them.

METHODS

A total of 231 recipients were included in the retrospective, longitudinal, and nonrandomized study.

RESULTS

The overall survival of the transplant was 85.2% (197 patients). The most frequent cause of death was infection (38.2%), followed by the multiorgan failure of multiple etiology (23.5%). Most of the risk factors related to mortality correspond to variables of the postoperative period. The results of the multivariate analysis identified the main risk factors for death: the presence of surgical complications and the need for renal replacement therapy. In contrast, the performance of PCS exerted a protective effect, reducing the probability of death by 70%.

CONCLUSIONS

Despite the good results obtained in several studies, there is still debate regarding the benefit of its realization. In our study, PCS was a factor associated with a reduction in mortality, with a markedly lower probability of adverse events. However, we agree with other authors on the need for larger and randomized studies to adequately determine the validity of such results.

Intraoperative Oxygen Delivery and Acute Kidney Injury after Liver Transplantation

Although intraoperative hemodynamic variables were reported to be associated with acute kidney injury (AKI) after liver transplantation, the time-dependent association between intraoperative oxygen delivery and AKI has not yet been evaluated. We reviewed 676 cases of liver transplantation. Oxygen delivery index (DO2I) was calculated at least ten times during surgery. AKI was defined according to the Kidney Disease Improving Global Outcomes criteria. The area under the curve (AUC) was calculated as below a DO2I of 300 (AUC < 300), 400 and 500 mL/min/m2 threshold. Also, the cumulative time below a DO2I of 300 (Time < 300), 400, and 500 mL/min/m2 were calculated. Multivariable logistic regression analysis was performed to evaluate whether AUC < 300 or time < 300 was independently associated with the risk of AKI. As a sensitivity analysis, propensity score matching analysis was performed between the two intraoperative mean DO2I groups using a cutoff of 500 ml/min/m2, and the incidence of AKI was compared between the groups. Multivariable analysis showed that AUC < 300 or time < 300 was an independent predictor of AKI (AUC < 300: odds ratio [OR] = 1.10, 95% confidence interval [CI] 1.06-1.13, time < 300: OR = 1.10, 95% CI 1.08-1.14). Propensity score matching yielded 192 pairs of low and high mean DO2I groups. The incidence of overall and stage 2 or 3 AKI was significantly higher in the lower DO2I group compared to the higher group (overall AKI: lower group, n = 64 (33.3%) vs. higher group, n = 106 (55.2%), P < 0.001). In conclusion, there was a significant time-dependent association between the intraoperative poor oxygen delivery <300 mL/min/m2 and the risk of AKI after liver transplantation. The intraoperative optimization of oxygen delivery may mitigate the risk of AKI.

Impact of early remote organ dysfunction on long-term survival after liver transplantation

BACKGROUND

Attention is focused on graft function although extrahepatic organ dysfunction often occurs. Renal failure, cardiovascular events and sepsis have individually shown a significant impact on short- and long-term outcomes. The aim of the study was to identify how extrahepatic organ dysfunction (EROD) and allograft dysfunction (EAD) may be associated and their relative impact on long-term survival.

METHODS

A retrospective study was conducted in a unicentric cohort of 294 patients transplanted between 2009 and 2014. The composite endpoint EROD was defined as requirement during the hospitalization of de novo renal replacement therapy, reintubation/ventilation > 7 days or cardiovascular event. Donor and recipient characteristics were evaluated as predictive of EROD in uni- and multivariate analysis. Main endpoint was overall survival evaluated by Kaplan-Meier method.

RESULTS

EROD occurred in 91 patients (31%) among whom 42 also experienced EAD (46%). Predicting factors associated with EROD were IL6 level (P = 0.002) and lab-MELD (P < 0.001). Only patients experiencing both EAD and EROD had a worse survival (P = 0.001). In patients without EAD, time to normalization of bilirubin and INR were longer in patients with EROD compared to those without EROD (P = 0.002 and P = 0.008 respectively).

CONCLUSIONS

The composite endpoint described as early remote organ dysfunction could be used as a predictive factor after transplantation and should be included in future studies together with early allograft dysfunction. Identifying patients in whom EROD and EAD occur together or one after the other could help to better predict long-term outcomes.

Impact of Temporary Portocaval Shunting and Initial Arterial Reperfusion in Orthotopic Liver Transplantation

The use of a temporary portocaval shunt (TPCS) as well as the order of reperfusion (initial arterial reperfusion [IAR] versus initial portal reperfusion) in orthotopic liver transplantation (OLT) is controversial and, therefore, still under debate. The aim of this study was to evaluate outcome for the 4 possible combinations (temporary portocaval shunt with initial arterial reperfusion [A+S+], temporary portocaval shunt with initial portal reperfusion, no temporary portocaval shunt with initial arterial reperfusion, and no temporary portocaval shunt with initial portal reperfusion) in a center-based cohort study, including liver transplantations (LTs) from both donation after brain death and donation after circulatory death (DCD) donors. The primary outcome was the perioperative transfusion of red blood cells (RBCs), and the secondary outcomes were operative time and patient and graft survival. Between January 2005 and May 2017, all first OLTs performed in our institution were included in the 4 groups mentioned. With IAR and TPCS, a significantly lower perioperative transfusion of RBCs was seen (P < 0.001) as well as a higher number of recipients without any transfusion of RBCs (P < 0.001). A multivariate analysis showed laboratory Model for End-Stage Liver Disease (MELD) score (P < 0.001) and IAR (P = 0.01) to be independent determinants of the transfusion of RBCs. When comparing all groups, no statistical difference was seen in operative time or in 1-year patient and graft survival rates despite more LTs with a liver from a DCD donor in the A+S+ group (P = 0.005). In conclusion, next to a lower laboratory MELD score, the use of IAR leads to a significantly lower need for perioperative blood transfusion. There was no significant interaction between IAR and TPCS. Furthermore, the use of a TPCS and/or IAR does not lead to increased operative time and is therefore a reasonable alternative surgical strategy.