ROTEM-based Optimization of Anticoagulation Regimens in Lung Transplantation

Extracorporeal membrane oxygenation (ECMO) is now a standard component of intraoperative support during lung transplantation, requiring anticoagulation management, typically with unfractionated heparin (UFH). While monitoring methods such as Activated Partial Thromboplastin Time (aPTT), Activated Partial Thromboplastin Time Ratio (aPTTr), Anti-Factor Xa Activity (anti-Xa), and Activated Clotting Time (ACT) are commonly used, a reliable bedside method remains elusive due to the unreliability of ACT at low UFH doses. This study evaluates the correlation among these monitoring methods and investigates the potential of the ROTEM Clotting Time INTEM/HEPTEM ratio (I/Hr) as a bedside alternative.

Investigators conducted a comprehensive analysis of all lung transplant cases performed between December 8, 2022, and July 13, 2024, as part of the Prague Lung Transplant Program. This study was designed to assess the feasibility of using the ROTEM Clotting Time INTEM/HEPTEM ratio (I/Hr) as a reliable and practical bedside method for monitoring anticoagulation during lung transplantation procedures supported by extracorporeal membrane oxygenation (ECMO). Inclusion criteria focused on patients who underwent double lung transplantation, required intraoperative ECMO support, and had complete laboratory data available. Based on these parameters, investigators included 65 patients in our analysis. All enrolled patients received unfractionated heparin (UFH) for anticoagulation management during their lung transplant procedures. Coagulation was closely monitored at three critical time points: preoperatively (using the most recent laboratory results prior to surgery), immediately before ECMO cannulation (following UFH administration but prior to initiating ECMO support), and during the ECMO run (after the reperfusion of the first transplanted lung). To ensure a comprehensive assessment, coagulation status was evaluated using a combination of methods: Activated Partial Thromboplastin Time (aPTT), Activated Partial Thromboplastin Time Ratio (aPTTr), Anti-Factor Xa Activity (anti-Xa), Activated Clotting Time (ACT), and the ROTEM Clotting Time INTEM/HEPTEM ratio (I/Hr). In all cases, ECMO was initiated using a centrally cannulated approach. The drainage cannula was inserted through the right atrial appendage, while the return cannula was positioned in the ascending aorta. This configuration ensured optimal support and minimized complications during the intraoperative period. Extracorporeal circulation was facilitated using advanced devices, including Rotaflow I and Cardiohelp systems, both equipped with heparin-coated ECMO circuits to enhance biocompatibility and reduce clot formation. Laboratory analyses of aPTT, aPTTr, and anti-Xa levels were performed in the institution's central laboratory, adhering to standardized methodologies to ensure accuracy and consistency. Bedside monitoring of ACT was carried out using the Werfen - HemoChron® system, which provided real-time feedback on clotting status during the procedure. Additionally, viscoelastic testing was performed to provide a detailed assessment of coagulation dynamics. This was primarily conducted using the Werfen - ROTEM® Sigma device, although the ROTEM® Delta device was employed in instances where the primary system was unavailable. This study aims to establish the utility of the I/Hr as a novel, reliable, and bedside-appropriate method for anticoagulation monitoring during lung transplantation supported by ECMO. By comparing this approach to established monitoring methods, such as aPTT, anti-Xa, and ACT, investigators hope to identify a more effective strategy that aligns with the unique anticoagulation challenges posed by ECMO support. Investigator's findings could pave the way for standardized and improved anticoagulation protocols in lung transplant patients, ultimately enhancing clinical outcomes.