Received Date: June 12, 2017; Accepted Date: July 14, 2017; Published Date: July 14, 2017
Citation: Nascimento JCR, Escalantea RD, Marinhob DS, Fernandesc CR, Freireb TL, et al. (2017) Profile of Coagulation Guided by Rotational Thromboelastometry (ROTEM®) in Patients with Prothrombotic Risk Factors during Liver Transplantation. J Transplant Technol Res 7: 175. doi:10.4172/2161-0991.1000175
Copyright: © 2017 Nascimento JCR, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution and reproduction in any medium, provided the original author and source are credited.
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Background: Orthotopic liver transplantation (OLT) is a highly complex procedure and can offer difficult intraoperative control in patients with coagulopathy. The present study aimed to evaluate the profile of coagulation by Rotation thromboelastometry (ROTEM®) in the intraoperative of patients with prothrombotic risk factors submitted to liver transplantation. Methods: A prospective, observational pilot study, in which 24 patients submitted to OLT, of both sexes and age from 18 years, were included in the period from October 2014 to June 2017. Three samples were taken intraoperatively to analyze the profile of coagulation through the thromboelastometry assays (EXTEM, FIBTEM, INTEM and HEPTEM). Results: In the analysis of the tests in the EXTEM (clotting time [CT] and maximum clot firmness [MCF]) and INTEM (MCF), there was hypocoagulation along the OLT, with no statistical difference between the values obtained. In the FIBTEM tests (amplitude in 10 minutes [A10] and MCF),There was reduction in the neohepatic phase (stage III) in relation to the beginning of surgery (stage I), with statistical significance (P=0.0424 and 0.0227, respectively). In the analysis of CT in the INTEM, there was an increase in the stage III in relation to stage I and anhepatic phase (stage II), with statistical significance (P=0.0004 and 0.0012, respectively). The fibrinolytic activity by maximum lysis (ML) was higher in the stage I and stage II in relation to stage III, when analyzed by the EXTEM, presenting statistical significance (P=0.0016 and 0.0035, respectively). Conclusion: In patients with prothrombotic risk factors, data from the ROTEM® analysis showed some statistically significant changes, but we cannot say that it showed tendency to hypocoagulation, when there was not significance in most other tests. Therefore, in the FIBTEM tests the consumption of fibrinogen was more accentuated in stage III in relation to stage I and in relation to stage III, when analyzed by INTEM CT and EXTEM ML, the presence of heparin was higher and fibrinolysis was less pronounced, respectively.
Liver transplantation; Coagulation disorders; Thromboelastometry; Prothrombotic
OLT: Orthotopic Liver Transplantation; ROTEM: Rotation Thromboelastometry; CT: Clotting Time; ML: Maximum Lysis; Hb: Hemoglobin; MCF: Maximum Clot Firmness; A10: Amplitude in 10 minutes; ANOVA: Analysis of Variance; MELD: Model for End-Stage Liver Disease; PAI-1: Plasminogen Activator Inhibitor-1; t-PA: Tissue Plasminogen Activator; u-PA: Urokinase-type Plasminogen Activator
Orthotopic liver transplantation (OLT) is the treatment of choice for patients with late stage decompensated liver disease . It is a complex procedure with potentially difficult coagulopathy control, in the intraoperative period of patients presenting with coagulopathy and portal hypertension .
Historically, OLT has been linked to the need to transfuse large amounts of blood derivatives [3-7]. Currently, there is a progressive reduction of perioperative blood loss due to advances in surgical skills, anesthetics and coagulation monitoring in general [8-12].
Although the origin of hemorrhage is multifactorial, complex and profound coagulation changes are common during liver transplantation. The causes that still persist are related to preoperative coagulation disorders associated with the hepatic disease itself, hemostatic changes associated with the procedure itself and hemodilution, leading to an increase in intraoperative hemorrhage, especially due to the increase in fibrinolysis [13-18].
It is important to note that cirrhotic patients have a decrease in procoagulant factors (leading to bleeding) and anticoagulant factors (leading to thrombosis). They may also have thrombocytopenia, develop fibrinolysis and Von Willebrand factor abnormalities [19,20].
However, there is a fraction of poorly studied patients presenting prothrombotic risk factors with high hemostatic capacity, with modified local flow dynamics and several acquired and genetic factors such as those with Budd-Chiari syndrome, protein C deficiency, malignant disease, multiple organ transplants, and chronic renal failure, as well as portal vein or hepatic artery thrombosis revascularization, pre-existing thrombotic diseases and non-alcoholic steatohepatitis (NASH) [13,20-27].
Other risks for hypercoagulation also include the presence of primary biliary cirrhosis and primary sclerosing cholangitis, as the levels of coagulation factors (thrombin-antithrombin complex) and plasminogen activator inhibitor type 1 are higher [21-26]. Although several studies have shown coagulation changes during the intraoperative period of patients undergoing liver transplantation, there are few studies that specifically evaluate patients with prothrombotic risk factors. In the present study, we evaluated the intraoperative coagulation profile of this group of patients through ROTEM® monitoring.
This prospective observational pilot study was approved by the Institutional Review Board of the General Hospital of Fortaleza, Brazil (Protocol nr. 794061) on 10th September 2014. Written informed consent was obtained from the enrolled patients or their next of kin.
The population studied was of patients aged 18 years and a clinical pro-thrombotic profile with described by some authors [13,20-27] such as: Budd-Chiari syndrome, protein C deficiency, malignant disease, multiple organ transplants, chronic renal failure, retransplantation for portal vein and hepatic artery thrombosis, portal vein and hepatic artery thrombosis, primary biliary cirrhosis, submitted to orthotopic liver transplantation from October 2014 to June 2017.
All patients were submitted to liver transplantation by the piggyback surgical technique [4,12]. During the surgery the objective was to maintain a pH ≥ 7.3; Temperature ≥ 36°C, ionic calcium ≥ 1.1 mmol/L-1 and hemoglobin (Hb) ≥ 8 g/dL-1.
Blood samples were collected hourly for blood gas analysis and at three times for rotational thromboelastometry (ROTEM®, Pentapharm, Germany): at the beginning of surgery (stage I); before the portal vein anastomosis on anhepatic phase (stage II) and before the anastomosis of the bile ducts in the neohepatic phase (stage III).
Blood was collected to analyze fibrinolysis and changes in coagulation through thromboelastometry tests with the following: EXTEM and INTEM, Clotting time (CT), maximum clot firmness (MCF); EXTEM: maximum lysis (ML); FIBTEM: amplitude in 10 minutes (A10) and MCF; HEPTEM (CT).
Having obtained the results of the ROTEM® analysis, the values were compared to the normal values [28,29] and if corrections were necessary, together with clinical diagnosis of hypo coagulation and presence of micro vascular bleeding, were made based on hemostasis support protocol as described in Table 1.
|EXTEM CT>80-100 s||↓ plasma factors||PCC: 25-40 IU/kg-1 and/or
FFP: 15-20 ml/kg-1
|EXTEM A10<30 mm ou MCF<35 mm, FIBTEM MCF>9 mm||↓ platelets||Platelets: 1U for each 7 to 10 kg or 1 apheresis or 1 buffy coat|
|EXTEM A10<30 mm ou MCF<35 mm, FIBTEM MCF?9 mm||↓ fibrinogen||Fibrinogen (g)=MCF in ΔFIBTEM (mm) x weight (kg)/140|
|INTEM CT>240S e CTHEPTEM/CTINTEM<0,8||↑ heparin||Protamine: 50-100 mg|
|INTEM CT>240S e CTHEPTEM/CTINTEM ≥ 0,8||↓ plasma factors||FFP: 15-20 ml/kg-1|
|EXTEM ML>15% e APTEM ML?15%||↑ fibrinolysis||EACA: 50 mg/kg-1|
Table 1: Algorithm for treatment of coagulation disorders and fibrinolysis according to ROTEM®.
For normality, the D'Agostino & Pearson and Shapiro-Wilk tests were performed. In the parametric tests, analysis of variance (ANOVA) was used and the significance was studied by the Tukey's test for multiple comparisons with a 95% confidence interval. In nonparametric tests, Friedman test was used in association with the Dunn's test for multiple comparisons.
During the study period, 24 consecutive patients were identified with prothrombotic risk factors: hepatocellular carcinoma (n=11), with primary biliary cirrhosis and primary sclerosing cholangitis (n=05), retransplantation for hepatic artery thrombosis (n=04), portal vein thrombosis (n=02) and chronic renal failure and C virus (n=02). There were 13 male, the mean age of the patients of 51.8 ± 9.4 years and the Model for End-Stage Liver Disease (MELD) score 24.0 ± 6.92. Demographic and surgical data are summarized in the Table 2.
|Age||51.8 (± 9.4) years*|
|Weight||67.4 (± 13.9) kg*|
|Score MELD||24.0 (± 6.9)*|
PSC and PBC
Retransplantation for hepatic artery thrombosis
CRF and C virus
|Duration of surgery||341.7 (± 81.9) min*|
*Mean ± SD (Standard Deviation), MELD: Model for End-Stage Liver Disease; PSC and PBC: Primary Sclerosing Cholangitis (PSC) and Primary Biliary Cirrhosis (PBC); CRF: Chronic Renal Failure
Table 2: Demographic and surgical characteristics of the patients studied.
In the analysis of the tests in the EXTEM (CT and MCF), FIBTEM (A10 and MCF) and INTEM (MCF), there was hypo coagulation along the OLT, without statistical difference between the values obtained.
In the analysis of CT in the INTEM, there was an increase in the stage III in relation to stage I and stage II, with statistical significance (P<0.05), according to Figure 1. When the CTHEPITEM/CTINTEM ratio was analyzed, there was a reduction in the stage III in relation to stage I and stage II, without statistical significance. CT enlargement at INTEM was present in 17/24 cirrhotic patients (70.8%), of which, five (29.4%) were treated with protamine in stage III, two (11.8%) in stage II and two (11.8%) in stage I and stage III.
The analysis of the fibrinolytic activity in the EXTEM during the OLT was performed through the evaluation of ML during the surgery. The ML was higher in the stage I and stage II in relation to stage III, when analyzed by the EXTEM, presenting statistical significance (P<0.05), according to Figure 2. Hyperfibrinolysis (defined as EXTEM ML > 15% in 60 min, according to the hemostatic support of Table 2), was present in 3 of 24 cirrhotic patients (12.5%) in this study, being treated with epsilon aminocaproic acid (EACA), one in stage I and two in stage II.
The present study analyzed patients submitted to OLT with prothrombotic risk factors, which are believed to have a large hemostatic reserve, less fibrinolysis, low risk of blood loss and a greater predisposition to hypercoagulation or high risk of thromboembolic complications [24,27,30].
Krzanicki et al.  observed in a retrospective study with 124 patients undergoing OLT and monitoring with TEG®, a high rate of hypercoagulability in patients with primary biliary cirrhosis (85.7%) and in those with primary sclerosing cholangitis and fulminant hepatic insufficiency (50%).
Friedman test; stage I=beginning of surgery; stage II=anhepatic phase; stage III=neohepatic phase; CT=Clotting time; P<0.05.
Friedman test; stage I=beginning of surgery; stage II=anhepatic phase; stage III=neohepatic phase; ML=maximum lysis; P<0.05.
Ritter et al.  evidenced in a retrospective study that hemostatic parameters such as platelet counts, coagulation factors (II, V, VII, IX and X) and antithrombin III presented less changes in patients with primary biliary cirrhosis and primary sclerosing cholangitis, when Compared with chronic hepatitis.
In this series, cryoprecipitate, fresh frozen plasma, platelets, prothrombin complex concentrate and protamine were administered, when considered necessary as suggested by the intraoperative findings in ROTEM®, according to the algorithm of Table 1.
However, in spite of corrections with blood products, there was hypocoagulation in the thromboelastogram throughout the liver transplantation, corroborating with the blood loss, hemodilution and the consumption of coagulation factors that occur along the OLT [6,7,20].
Kettner et al.  demonstrated in one study that heparin-modified thromboelastography can identify the significant effects of heparin in the absence of exogenous heparin administration in patients undergoing OLT.
In this study, CT enlargement in the INTEM after reperfusion was represented in more than 53% of the patients due to the effect of heparin, in agreement with the study of Agarwal et al.  where they demonstrated in a retrospective and observational study of 211 patients undergoing liver transplantation that the prevalence of heparin was demonstrated in more than 80% of cases after reperfusion of the graft.
It is also important to mention that the fibrinolytic activity by ML in the EXTEM was less pronounced in stage III, measured after one hour of reperfusion, according to most studies, where the correction of hyperfibrinolysis usually occurs within one hour after reperfusion by the presence of hepatic clearance. As it is already well documented that the frequency of disorders associated with diseased organs such as platelet defects, decreased plasminogen activator inhibitor-1 (PAI-1), reduced synthesis and release of coagulation factors can lead to compromised hemostasis and hyperfibrinolysis, mainly during the an hepatic phase and immediately after organ reperfusion. The explanation for these findings may be due to the presence of increased levels of tissue plasminogen activator (t-PA) and urokinase-type plasminogen activator (u-PA) in the pre-anesthetic and an hepatic phases as well as a pronounced release of t-PA of the endothelium of the graft soon after reperfusion and in the presence of the still nonperforming hepatic graft. [35-37].
Himmelreich et al.  identified a slight increase in u-PA and t-PA levels during the preoperative period and a slight decrease in the preanesthetic and hepatic phases. On the other hand, Dzik et al. [38,39] showed that there was a mild to moderate increase in u-PA antigen levels in some patients at the beginning of surgery, but the acute pathophysiological actions of systemic fibrinolytic activity are more influenced by t-PA in the anhepatic phase.
In this series the prominent fibrinolytic activity in the stage I and stage II and low in stage III by EXTEM, contradicted the study by Poon et al.  where fibrinolytic activity was low in beginning of surgery and anhepatic phase, rising soon after reperfusion in less than 30 minutes. As the samples were collected around 60 minutes after reperfusion, it is possible that the acute alterations of t-PA have already been dissipated , being able to explain the difference between the studies.
ROTEM® was able to guide the transfusion when there was a real need. Roullet et al.  concluded that ROTEM® is useful for the global evaluation of coagulation and the EXTEM was the most informative to evaluate the entire coagulation process. Therefore, the empirical use of blood products uncontrolled by ROTEM® should not be considered in the current real evidence in the literature .
The present study has as limitations the observational nature of the research, small sample and no measurement of intraoperative bleeding. It is important to carry out prospective and randomized studies to be conducted in the future with a larger sample and prothrombotic risk factors derived from an actual hypercoagulability system, such as laboratory tests (anti-phospholipid antibodies, factor V Leiden SNP or protein C and S abnormalities), analyzing whether the administration of small doses of antifibrinolytics would reduce fibrinolysis and consequently bleeding in the perioperative period.
In conclusion, although the patients in this series may be prothrombotic, our results showed some statistically significant changes, but we cannot say that it showed a tendency to hypocoagulation, when there was no significance in most other ROTEM® tests. The diagnosis of the presence of heparin and/or heparinoids was superior in the neohepatic phase, being corrected effectively with the use of protamine, guided by thromboelastotometry and moreover, in this research fibrinolysis was more pronounced at the beginning of the transplantation and in the anhepatic phase.