Area of Concentration: Anesthesiology

Keywords: Donation after cardiac death, normothermic machine perfusion, liver transplant, coagulopathy, ROTEM, postreperfusion syndrome.

Background: In liver transplantation, donation after cardiac death (DCD) using cold storage techniques has been associated with increased incidence of reperfusion syndrome, early allograft dysfunction, and ischemic biliary complications. With the advent of normothermic machine perfusion (NMP), early data suggests a more stable postreperfusion state with decreased coagulopathy and improved graft outcomes. While NMP as a preservation technique may increase the use of marginal grafts, such as DCD grafts, perioperative hemostatics in this population are not well studied.

Objectives: We performed a retrospective pilot review to examine baseline and postreperfusion rotational thromboelastometry (ROTEM) data in NMP DCD liver transplant (LT) recipients. 

Methods: We conducted a retrospective review of adult patients who underwent LT from November 2022 to October 2024 and received a NMP DCD graft at our institution. Re-transplants and combined heart-liver transplants were excluded. Blood samples for ROTEM were collected at baseline (after induction of general anesthesia) and postreperfusion. Clotting time (CT) and maximum clot firmness (MCF) from the ROTEM EXTEM assay, as well as MCF from the ROTEM FIBTEM assay are reported as mean ±standard deviation. Student’s t-test was used to compare baseline and postreperfusion ROTEM values with p<0.05 considered statistically significant. 

Results: Our study included 25 adult LT patients. All patients except one liver-kidney transplant patient underwent LT only. The mean age was 52.3±13.1 years; the mean model for end-stage liver disease model (MELD) score was 31.0±7.54. Most patients were male (76%). The most common liver failure diagnosis was alcoholic cirrhosis (52%), followed by nonalcoholic steatohepatitis (24%), hepatocellular carcinoma (20%), viral hepatitis (12%), alcoholic hepatitis (4%) and Wilson’s Disease (4%). Most grafts (92%) were preserved with Organ Care System (Transmedics); 8% were preserved with OrganOx (OrganOx). Baseline and postreperfusion ROTEM values are summarized in Table 1. 

Table 1: ROTEM (FIBTEM, EXTEM) values in patients receiving NMP DCD grafts

CT, clotting time; MCF, maximum clot firmness; ROTEM, rotational thromboelastometry; NMP, normothermic machine perfusion; DCD, donation after cardiac death.

ROTEM analysis demonstrated slight decreases in postreperfusion mean MCF values for both EXTEM and FIBTEM but did not achieve statistical significance when compared to baseline values. Postreperfusion mean EXTEM CT was slightly lower compared to baseline but did not achieve statistical significance.

Conclusion: In this pilot study of viscoelastic parameters of coagulation in a cohort of DCD LT patients, our results suggest NMP DCD grafts demonstrate hemostatic stability postreperfusion. Further investigation with head-to-head comparison of NMP DCD grafts versus DCD standard cold preserved grafts are warranted to better characterize postreperfusion hemostatics and outcomes in this population.