Mild Hypothermia and Acute Kidney Injury in Liver Transplantation (MHALT)

Acute kidney injury (AKI), or worsening kidney function, is a common complication after liver transplantation (20-90% in published studies). Patients who experience AKI after liver transplantation have higher mortality, increased graft loss, longer hospital and intensive care unit stays, and more progression to chronic kidney disease compared with those who do not. In this study, half of the participants will have their body temperature cooled to slightly lower than normal (mild hypothermia) for a portion of the liver transplant operation, while the other half will have their body temperature maintained at normal. The study will evaluate if mild hypothermia protects from AKI during liver transplantation.

This study is a single-blinded, randomized controlled trial of mild hypothermia during liver transplantation to provide protection from AKI. Participants will be randomized to normothermia (36.5-37.5 °C) versus mild hypothermia (34-35 °C) during a portion of the liver transplant operation. The protocol is based on preliminary data from rodent models showing that hypothermia protects the kidneys from ischemia-reperfusion injury, as well as studies in deceased organ donors showing that cooling improves post-transplant organ function. Temperature will be maintained with standard techniques plus a minimally-invasive esophageal cooling device that is approved by the U.S. Food and Drug Administration. The investigators hypothesize that mild hypothermia will reduce the incidence and severity of AKI after LTx. Standard surrogates (e.g., change in serum creatinine, need for initiation of dialysis) and biomarkers will be used to assess the severity of kidney injury.

Cirrhosis, End Stage Liver Disease, Acute Kidney Injury, Liver Transplant; Complications, Chronic Kidney Diseases, Hepatitis c, Hepatitis B, NASH - Nonalcoholic Steatohepatitis, Alcoholic Cirrhosis, Hepatocellular Carcinoma

The EnsoETM (formerly known as Esophageal Cooling Device) is a non-sterile multilumen silicone tube placed in the esophagus for the purpose of cooling or warming a patient while allowing gastric decompression and drainage. It is placed in a manner identical to a standard orogastric tube, which is standard equipment for liver transplant surgery. It is removed at the end of surgery. Control of the patient's temperature is achieved by connecting the EnsoETM to an external heat exchanger (Gaymar Medi-Therm III or similar system). The Medi-Therm III is a standard device used in operating rooms for warming patients with a conductive table warming pad. The Medi-Therm III circulates temperature-controlled water through a closed-loop system via the two outer lumens of the EnsoETM. Water temperature ranges from 4°C - 42°C.

Cooling will be initiated after induction of anesthesia and maintained throughout the anhepatic phase of liver transplantation. In all feasible cases the surgeon will cover the peritoneal surface over the right kidney, which is exposed during the operation, with ice-cold sponges to enhance cooling of the renal parenchyma. After blood flow is completely restored to the liver, the esophageal cooling device and other standard measures (forced-air, fluid, and table warmers, plus a heated anesthesia circuit) will be used to actively re-warm the patient (expected warming rate ≥ 1 deg C/hour). The goal is to achieve normothermia by case end.

After induction of anesthesia, the esophageal cooling/warming device and standard warming measures will be used to maintain normothermia throughout the operation.

The International Club for Ascites (ICA) 2015 criteria, a revision of the Kidney Disease Improving Global Outcome (KDIGO) criteria for patients with cirrhosis, will be used to define AKI. A predefined subgroup analysis of this primary outcome will be performed in patients undergoing liver transplantation for hepatocellular carcinoma (HCC) with Model for End-stage Liver Disease exception points.

The International Club for Ascites (ICA) 2015 criteria, a revision of the Kidney Disease Improving Global Outcome (KDIGO) criteria for patients with cirrhosis, will be used to define the stage of AKI (Stage 1, 2, or 3). A predefined subgroup analysis of this secondary outcome will be performed in patients undergoing liver transplantation for hepatocellular carcinoma (HCC) with Model for End-stage Liver Disease exception points.

The number of units of packed red blood cells, fresh frozen plasma, platelets, and cryoprecipitate transfused during the perioperative period.

Inclusion Criteria: Liver transplantation from a donor after neurologic determination of death Exclusion Criteria: Liver transplantation from a donor after cardiac death Acute liver failure Living-donor liver transplantation Simultaneous liver-kidney transplantation Preoperative renal replacement therapy Preoperative intubation Portopulmonary hypertension Machine perfusion of liver graft

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Niemann CU, Walia A, Waldman J, Davio M, Roberts JP, Hirose R, Feiner J. Acute kidney injury during liver transplantation as determined by neutrophil gelatinase-associated lipocalin. Liver Transpl. 2009 Dec;15(12):1852-60. doi: 10.1002/lt.21938.

Kalasbail P, Makarova N, Garrett F, Sessler DI. Heating and Cooling Rates With an Esophageal Heat Exchange System. Anesth Analg. 2018 Apr;126(4):1190-1195. doi: 10.1213/ANE.0000000000002691.

Karapanagiotou A, Dimitriadis C, Papadopoulos S, Kydona C, Kefsenidis S, Papanikolaou V, Gritsi-Gerogianni N. Comparison of RIFLE and AKIN criteria in the evaluation of the frequency of acute kidney injury in post-liver transplantation patients. Transplant Proc. 2014 Nov;46(9):3222-7. doi: 10.1016/j.transproceed.2014.09.161.

Kellum JA, Zarbock A, Nadim MK. What endpoints should be used for clinical studies in acute kidney injury? Intensive Care Med. 2017 Jun;43(6):901-903. doi: 10.1007/s00134-017-4732-1. Epub 2017 Mar 2. No abstract available.