Case Control Study
Copyright ©The Author(s) 2020. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Transplant. Nov 28, 2020; 10(11): 345-355
Published online Nov 28, 2020. doi: 10.5500/wjt.v10.i11.345
Intraoperative thromboelastography as a tool to predict postoperative thrombosis during liver transplantation
Lesley De Pietri, Roberto Montalti, Giuliano Bolondi, Valentina Serra, Fabrizio Di Benedetto
Lesley De Pietri, Department of General Surgery, Division of Anaesthesiology and Intensive Care Unit, Nuovo Ospedale Civile di Sassuolo, Sassuolo 41049, Modena, Italy
Roberto Montalti, Department of Public Health, Hepato-Pancreato-Biliary Surgery Section, Federico II University of Naples, Napoli 80138, Italy
Giuliano Bolondi, Surgery and Trauma Department, Intensive Care Unit, Ospedale Bufalini Cesena, Cesena 47521, Italy
Valentina Serra, Fabrizio Di Benedetto, Surgery Department, Hepato-Pancreato-Biliary Surgery, Surgical Oncology and Liver Transplantation Unit, Azienda Ospedaliero Universitaria di Modena, University of Modena and Reggio Emilia, Modena 41125, Italy
Author contributions: Bolondi G, Serra V, Di Benedetto F collected the data and drafted the paper; Montalti R analyzed the data and performed statistical analysis; De Pietri L designed the research study, drafted and supervised the paper; all authors have read and approve the final manuscript.
Institutional review board statement: The study was reviewed and approved by Institutional Review Board of Azienda Ospedliero Universitaria (No. 139/14 approved on October 29, 2014).
Informed consent statement: Patients were not required to give informed consent for this study as the analysis used anonymous clinical data that were obtained after each patient agreed to treatment by written consent.
Conflict-of-interest statement: All authors have no financial relationships to disclose.
Data sharing statement: No additional data are available.
STROBE statement: The authors have read the STROBE Statement, and the manuscript was prepared and revised according to the STROBE Statement (checklist of items).
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (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/
Corresponding author: Lesley De Pietri, MD, Chief Doctor, Director, Department of General Surgery, Division of Anaesthesiology and Intensive Care Unit, Nuovo Ospedale Civile di Sassuolo, Via Francesco Ruini 2, Sassuolo 41049, Modena, Italy. lesley.depietri@yahoo.it
Received: June 17, 2020
Peer-review started: June 17, 2020
First decision: July 25, 2020
Revised: July 28, 2020
Accepted: September 2, 2020
Article in press: September 2, 2020
Published online: November 28, 2020
Processing time: 158 Days and 22.5 Hours
Abstract
BACKGROUND

Thromboembolic complications are relatively common causes of increased morbidity and mortality in the perioperative period in liver transplant patients. Early postoperative portal vein thrombosis (PVT, incidence 2%-2.6%) and early hepatic artery thrombosis (HAT, incidence 3%-5%) have a poor prognosis in transplant patients, having impacts on graft and patient survival. In the present study, we attempted to identify the predictive factors of these complications for early detection and therefore monitor more closely the patients most at risk of thrombotic complications.

AIM

To investigate whether intraoperative thromboelastography (TEG) is useful in detecting the risk of early postoperative HAT and PVT in patients undergoing liver transplantation (LT).

METHODS

We retrospectively collected thromboelastographic traces, in addition to known risk factors (cold ischemic time, intraoperative requirement for red blood cells and fresh-frozen plasma transfusion, prolonged operating time), in 27 patients, selected among 530 patients (≥ 18 years old), who underwent their first LT from January 2002 to January 2015 at the Liver University Transplant Center and developed an early PVT or HAT (case group). Analyses of the TEG traces were performed before anesthesia and 120 min after reperfusion. We retrospectively compared these patients with the same number of nonconsecutive control patients who underwent LT in the same study period without developing these complications (1:1 match) (control group). The chosen matching parameters were: Patient graft and donor characteristics [age, sex, body mass index (BMI)], indication for transplantation, procedure details, United Network for Organ Sharing classification, BMI, warm ischemia time (WIT), cold ischemia time (CIT), the volume of blood products transfused, and conventional laboratory coagulation analysis. Normally distributed continuous data are reported as the mean ± SD and compared using one-way Analysis of Variance (ANOVA). Non-normally distributed continuous data are reported as the median (interquartile range) and compared using the Mann-Whitney test. Categorical variables were analyzed with Chi-square tests with Yates correction or Fisher’s exact test depending on best applicability. IBM SPSS Statistics version 24 (SPSS Inc., Chicago, IL, United States) was employed for statistical analysis. Statistical significance was set at P < 0.05.

RESULTS

Postoperative thrombotic events were identified as early if they occurred within 21 d postoperatively. The incidence of early hepatic artery occlusion was 3.02%, whereas the incidence of PVT was 2.07%. A comparison between the case and control groups showed some differences in the duration of surgery, which was longer in the case group (P = 0.032), whereas transfusion of blood products, red blood cells, fresh frozen plasma, and platelets, was similar between the two study groups. Thromboelastographic parameters did not show any statistically significant difference between the two groups, except for the G value measured at basal and 120’ postreperfusion time. It was higher, although within the reference range, in the case group than in the control group (P = 0.001 and P < 0.001, respectively). In addition, clot lysis at 60 min (LY60) measured at 120’ postreperfusion time was lower in the case group than in the control group (P = 0.035). This parameter is representative of a fibrinolysis shutdown (LY60 = 0%-0.80%) in 85% of patients who experienced a thrombotic complication, resulting in a statistical correlation with HAT and PVT.

CONCLUSION

The end of surgery LY60 and G value may identify those recipients at greater risk of developing early HAT or PVT, suggesting that they may benefit from intense surveillance and eventually anticoagulation prophylaxis in order to prevent these serious complications after LT.

Keywords: Thromboelastography; Hepatic artery thrombosis; Portal vein thrombosis; Liver transplantation; Risk factors; Cirrhosis

Core Tip: In this study, factors associated with an increased risk of early hepatic artery (HAT) and portal vein thrombosis (PVT) after adult liver transplantation (LT) were identified. In particular, basal and 120’ postreperfusion G value (increased net clot strength), and LY60 measured at 120’ postreperfusion time, were predictors of early HAT and PVT. Longer cold ischemic time was also significantly correlated with these complications. Intraoperative blood products transfusion was not associated with an increased risk of thrombosis. Increased daily surveillance by Doppler ultrasound should be considered for the possible prevention or early detection of HAT after LT for patients at increased risk of early HAT and PVT.