Patients: Adult patients (>21 years of age) with cirrhosis who were scheduled to undergo an elective invasive procedure were screened for the eligibility of the study. Patients with coagulopathy based on CCT (platelet count < 50,000/mm3 and /or INR >1.5) and able to give informed consent were randomized. The major exclusions (Table 1) were emergency or life-saving procedures, on-going active bleeding, known coagulation disorders other than those relating to liver disease, use of anticoagulant medications (e.g. warfarin, enoxaparin, rivaroxaban, dabigatran, apixaban, heparin, clexane etc.), anti-platelet aggregation agents other than aspirin (e.g. clopidogrel, ticagrelor), active malignancy except hepatocellular carcinoma, patients who have received FFP, platelet transfusion, cryoprecipitate within last 7 days, with stage 4 or 5 chronic kidney disease or on renal replacement therapy, in active sepsis as defined by the third international consensus definition of sepsis and septic shock criteria [17] or pregnancy. The inclusion and exclusion criteria for the study were well defined and are summarized in Table 1. Briefly, we included adult cirrhotic patients with coagulopathy and undergoing an elective procedure. The diagnosis of cirrhosis was based on established clinical, biochemical, imaging, as determined by hepatologists.
During the study period one major and 4 minor amendments were made to the study protocol. The major amendment in the protocol was to allow for an embedded observational study where patients with acute on chronic liver failure (ACLF) were recruited, these patients were not part of the randomized trial. The minor amendments were carried out to primarily to add or remove study team members.
Study Design: In this open label, randomized, controlled, intention to treat trial, patients meeting inclusion and exclusion criteria were randomized into ROTEM or standard or care (SOC) group. The patients randomized to SOC group received pre-emptive blood products according to current institutional practice and patients in the ROTEM™ group received pre-emptive transfusion based on ROTEM™ value guided transfusion triggers. In case a patient requires pre-emptive transfusion, CCT and ROTEM™ were repeated within 2 hours after completion of transfusion. The transfusion triggers in both groups were as follows
SOC Group: Patients in this group received FFP at the dose of 10 ml/kg of ideal body weight if INR > 1.5 and 1 unit of pooled platelets when the platelet count was below 50,000/mm3.
ROTEM Group: ROTEM™ cut offs for transfusion were based on pre-existing institutional guidelines, which is based on trauma guidelines. One unit of pooled platelets (CSP) was transfused if EXTEM MCF was less than 45mm and FIBTEM MCF greater than or equal to 10mm irrespective of platelet count. Patients received FFP at a dose of 10 mL/kg of ideal body weight if EXTEM CT > 80 seconds or INTEM CT >240 seconds irrespective of INR/PT/APTT. To avoid interference of ascites and/or pleural effusion, the amount of blood products administered both in SOC and ROTEM group was based on ideal body weight, which was calculated using the Devine formula. FFP transfusion was completed before starting the procedure.
Outcomes measures: Efficacy Assessment
The primary outcome measure was the volume of fresh frozen plasma (in ml) pre-emptively transfused. We also compare the volume of cryoprecipitate (in units) and platelet transfusion (ml and units) between ROTEM and SOC group.
The secondary outcomes were: 1) peri-procedural bleeding complications defined as an overt bleeding or hemoglobin drop (>2 gm) requiring packed red cell transfusion, 2) transfusion related side effects defined as any side effect occurring within 6 hours of blood product transfusion 3) procedure related complications other than bleeding, 4) length of stay in hospital, 5) thrombotic complications and survival at 30 and 90 days.
The study was conducted according to the protocol, the ethical principles originating from the Declaration of Helsinki, and consistent with ICH Guidelines. All aspects of this study were conducted in accordance with all national laws of the regulatory authorities. The study was monitored and supervised through regular review by an independent safety monitoring board. Data management, study monitoring and analysis of samples were performed by independent individuals not directly involved in patient recruitment. All patients provided written informed consent. The study protocol was approved by the institutional review board of SingHealth (2020/3087; Clinical Trial ID: NCT 05698134).
Standard Management
All patients underwent baseline assessment with review of clinical history, clinical paraments and lab works including full blood count (FBC), renal panel (RP), liver function tests (LFT’s), blood typing and cross matching (GXM), conventional tests of coagulation (PT/INR, aPTT), fibrinogen levels and ROTEM test before the procedure on the on the same day. Patients were observed after the procedure for any kind of immediate complications. If patients developed symptoms based on physician’s discretion an imaging study was performed (either a computed tomography or an ultrasound scan). All patients had their post procedure blood tests repeated 48 hours after the procedure. The patients were followed up via phone calls on 30 and 90 days from procedure.
Method of ROTEM™ determination
ROTEM™ test was done according to manufacturer’s instructions. It was performed after taking venous blood sample from the anti-cubital vein. ROTEM™ was performed before the elective procedure on native blood sample by a fully automated ROTEM™ sigma machine (ROTEM™, TEM, Munich, Germany). Sample was processed for 30 min and various parameters determined by the ROTEM™ was automatically recorded by machine.
Definition of various parameters in ROTEM™
The ROTEM™ device measures the time dependent development of clot firmness of a whole blood sample. Thus, the involvement of coagulation factors and platelets both can be investigated. There are four important variables obtained from the ROTEM thrombo-elastogram [18,19]. The clotting time defined as the time from recalcification and activation of the samples to clot formation is prolonged in patients with coagulation deficiencies, heparin therapy, or on oral anticoagulation. Clot formation time and angle alpha describe the kinetics of clot formation. Maximum clot firmness is affected by fibrinogen levels and platelet count. Four tests were used in the present study. EXTEM™ activates coagulation by the addition of tissue factor and has similarities to INR. INTEM™ is activated by elagic acid, which is an activator of the intrinsic system similar to laboratory aPTT. FIBTEM™ is an assay activated by tissue factor in the presence of a platelet inhibitor (cytochalasin D) and maximum clot firmness in FIBTEM is therefore a specific measure of fibrinogen concentration. APTEM™ is a tissue factor activated assay combined with a fibrinolysis inhibitor (aprotinin). Hyperfibrinolysis can be diagnosed by comparison of EXTEM™ and APTEM™ curves.
At the end of the procedure all patients were clinically reassessed and the blood tests including ROTEM and CCT’s were repeated if patients received any transfusion. Any bleeding episode and patients’ complaints were recorded and evaluated accordingly. Procedures were performed by experienced operators and bleeding events were classified according to the World Health Organization’s bleeding score [20]. Daily patient assessment was carried out till discharge from hospital. Weekly phone calls were made to assess patients’ general well-being and survival at 30 and 90 days.
Statistical Analysis
Sample size determination and power calculations: Based on the prevailing institutional practice, patients deemed to be coagulopathic (INR >1.5 and or platelet counts <50,000/uL) are pre-emptively transfused blood products before an invasive procedure. Our institutional preliminary data shows that on average 400-500 ml of FFP is transfused pre-emptively before invasive procedures in these patients. In this study we hypothesized that the use of ROTEM™ guided prophylactic blood product transfusion will result in at least 20% reduction in the volume of blood product transfusion. Assuming a 20% difference in the transfusion requirement (400 ± 100 mL in the SOC group and 320 ± 80 mL in ROTEM group) with a 5% alpha error and a 10% beta error, 33 patients in each group will be required. With a 10% drop out rate, it was planned to randomize 37 patients in each arm (74 patients in total) in 1:1 fashion. A scheduled interim analysis for primary outcome was planned after enrollment of 40 patients, and the study recruitment may be stopped if primary outcome measure been met at a significance level of 0.001 in accordance with Haybittle-Peto boundaries [21].
Randomization procedures and blinding: All eligible patients who met the predefined inclusion and exclusion criteria and consented for participation in the study were randomized with help of computer-generated random sequence by a statistician in variable blocks of 4 and 6. The random number was delivered in sealed and opaque envelopes. Patients were randomized in either SOC or ROTEM™ group by the study coordinator. The group allocation was concealed from the patient and the proceduralist. The screening and randomization scheme is illustrated in the CONSORT Diagram (Figure 1).
Statistical software SPSS (version 28, SPSS Inc. Chicago, IL, USA) and GraphPad were used for analysis. Normally distributed continuous variables are expressed as mean (standard deviation) and the continuous variables with skewed distribution are expressed as median (interquartile range). Student T test and Mann-Whitney U test was used for continuous variables that were normally distributed or non-normally distributed. Chi-square or Fishers test for discrete variables, wherever applicable. A two tailed paired t-test was used to compare paired variables before and after the procedure. Kaplan-Meier’s analysis was used to compare the cumulative probability of survival between the ROTEM and SOC group. The P value of <0.05 was of statistical significance.
The centralized institution review approval, patient information sheet, trial protocol with data analysis plan are available as supplementary material.