Retrospective Cohort Study
Copyright ©The Author(s) 2016. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Transplant. Sep 24, 2016; 6(3): 583-593
Published online Sep 24, 2016. doi: 10.5500/wjt.v6.i3.583
Thromboelastographic reference ranges for a cirrhotic patient population undergoing liver transplantation
Lesley De Pietri, Marcello Bianchini, Gianluca Rompianesi, Elisabetta Bertellini, Bruno Begliomini
Lesley De Pietri, Division of Anaesthesiology and Intensive Care Unit, Department of Cardiology, Thoracic and Vascular Surgery, Critical Care Medicine, Arcispedale Santa Maria Nuova, 42123 Reggio Emilia, Italy
Marcello Bianchini, Gastroenterology Unit, Department of Internal Medicine, Azienda Ospedaliero, Universitaria di Modena, 41100 Modena, Italy
Gianluca Rompianesi, Liver and Multivisceral Transplant Center, Azienda Ospedaliero-Universitaria di Modena, 41100 Modena, Italy
Elisabetta Bertellini, Bruno Begliomini, Division of Anaesthesiology and Intensive Care Unit, Department of Surgery, Azienda Ospedaliero, Universitaria di Modena, 41100 Modena, Italy
Author contributions: De Pietri L conceived the study and drafted the article; Bianchini M contributed to data analysis and attests the integrity of the original data and the analysis; Rompianesi G contributed to data analysis and attests the integrity of the original data and the analysis; Bertellini E participated in the acquisition of the data and Begliomini B revised the article critically for important intellectual content.
Institutional review board statement: The study was reviewed and approved by the Institutional Review Board of Azienda Ospedaliera-Universitaria, Modena (139/14 Trigger) and was conducted in accordance with provisions of the Declaration of Helsinki and Good Clinical Practice guidelines.
Informed consent statement: All patients or their legal guardian, provided a written informed consent prior to study enrolment.
Conflict-of-interest statement: All the Authors have no conflict of interest related to the manuscript.
Data sharing statement: The original anonymous dataset is available on request from the corresponding author at lesley.depietri@yahoo.it.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Lesley De Pietri, MD, Division of Anaesthesiology and Intensive Care Unit, Department of Cardiology, Thoracic and Vascular Surgery, Critical Care Medicine, Arcispedale Santa Maria Nuova, IRCCS, Viale Risorgimento 80, 42123 Reggio Emilia, Italy. lesley.depietri@asmn.re.it
Telephone: +39-059-4225864 Fax: +39-059-4224100
Received: April 11, 2016
Peer-review started: April 12, 2016
First decision: June 12, 2016
Revised: June 21, 2016
Accepted: August 15, 2016
Article in press: August 16, 2016
Published online: September 24, 2016
Processing time: 165 Days and 21.2 Hours
Abstract
AIM

To describe the thromboelastography (TEG) “reference” values within a population of liver transplant (LT) candidates that underline the differences from healthy patients.

METHODS

Between 2000 and 2013, 261 liver transplant patients with a model for end-stage liver disease (MELD) score between 15 and 40 were studied. In particular the adult patients (aged 18-70 years) underwent to a first LT with a MELD score between 15 and 40 were included, while all patients with acute liver failure, congenital bleeding disorders, and anticoagulant and/or antiplatelet drug use were excluded. In this population of cirrhotic patients, preoperative haematological and coagulation laboratory tests were collected, and the pretransplant thromboelastographic parameters were studied and compared with the parameters measured in a previously studied population of 40 healthy subjects. The basal TEG parameters analysed in the cirrhotic population of liver candidates were as follows: Reaction time (r), coagulation time (k), Angle-Rate of polymerization of clot (αAngle), Maximum strenght of clot (MA), Amplitudes of the TEG tracing at 30 min and 60 min after MA is measured (A30 and A60), and Fibrinolysis at 30 and 60 min after MA (Ly30 and Ly60). The possible correlation between the distribution of the reference range and the gender, age, MELD score (higher or lower than 20) and indications for transplantation (liver pathology) were also investigated. In particular, a MELD cut-off value of 20 was chosen to verify the possible correlation between the thromboelastographic reference range and MELD score.

RESULTS

Most of the TEG reference values from patients with end-stage liver disease were significantly different from those measured in the healthy population and were outside the suggested normal ranges in up to 79.3% of subjects. Wide differences were found among all TEG variables, including r (41.5% of the values), k (48.6%), α (43.7%), MA (79.3%), A30 (74.4%) and A60 (80.9%), indicating a prevailing trend to hypocoagulability. The differences between the mean TEG values obtained from healthy subjects and the cirrhotic population were statistically significant for r (P = 0.039), k (P < 0.001), MA (P < 0.001), A30 (P < 0.001), A60 (P < 0.001) and Ly60 (P = 0.038), indicating slower and less stable clot formation in the cirrhotic patients. In the cirrhotic population, 9.5% of patients had an r value shorter than normal, indicating a tendency for faster clot formation. Within the cirrhotic patient population, gender, age and the presence of hepatocellular carcinoma or alcoholic cirrhosis were not significantly associated with greater clot firmness or enhanced whole blood clot formation, whereas greater clot strength was associated with a MELD score < 20, hepatitis C virus and cholestatic-related cirrhosis (P < 0.001; P = 0.013; P < 0.001).

CONCLUSION

The range and distribution of TEG values in cirrhotic patients differ from those of healthy subjects, suggesting that a specific thromboelastographic reference range is required for liver transplant candidates.

Keywords: Thromboelastography; Liver cirrhosis; Blood coagulation disorder; Liver transplantation; Reference values

Core tip: Thromboelastography provides a more comprehensive coagulation assessment than routine tests in cirrhotic patients. We evaluated the baseline thromboelastography (TEG) tracing and preoperative laboratory tests of cirrhotic patients undergoing liver transplant (LT) to generate a reliable picture of their coagulation profile. We also studied how TEG value distribution in cirrhotic patients could be modified by gender, age, model for end-stage liver disease score and liver disease characteristics. End-stage liver disease is associated with considerable changes in TEG variables, which should be allowed for when interpreting TEG traces in cirrhotic patients. TEG reference values derived from a healthy population could be misleading in the management of cirrhotic patients during LT.