Impact of Cardiac Surgery With a Minimal Invasive Extracorporeal Circuit οn Coagulation: Data From Point of Care Devices
Condition: Extracorporeal Circulation; Complications; Coagulation Disorder; Extracorporeal Circulation of Blood; Thrombocytopenia
MeSH terms: Hemostatic Disorders; Thrombocytopenia; Blood Coagulation Disorders
Study type: Observational

Summary: 
      This study includes patients undergoing elective cardiac surgery on MiECC. Coagulation status
      is assessed with ROTEM (TEM International GmbH, Munich, Germany) and Platelet function with
      impedance aggregometry using the ROTEM-Platelet (TEM International GmbH, Munich, Germany).
    

Detailed description: 
      Last update: 24th October 2019, Thessaloniki, Greece

      Study protocol Objective Abnormal platelet function remains one of the main causes of severe
      bleeding during cardiac surgery, especially in the era of widespread evolution in
      antiplatelet therapy as standard of care in cardiac surgery patients. Additionally,
      conventional cardiopulmonary bypass is identified as a significant attributor to
      pathophysiologic derangement in coagulation and platelet dysfunction, induced by prolonged
      contact of blood with foreign surfaces, severe haemodilution, hypothermia and systemic
      inflammatory response. Minimally invasive extracorporeal circulation (MiECC) reflects the
      technological progress in cardiopulmonary circuits and offers improved perfusion conditions.
      The multiple electrode platelet aggregometry analysis can be a useful point-of-care
      diagnostic tool, assessing platelet receptors inhibition and aggregation, thus providing
      real-time information perioperatively. Our objective is to investigate the potential
      protective effect of MiECC on coagulation and platelet function and postoperative bleeding in
      a series of patients undergoing cardiac surgery.

      Design This is a prospective cohort study. 57 adult patients presented for elective cardiac
      surgery were recruited in the study. Informed consent was obtained by all patients. Exclusion
      criteria were defined as follows: unwillingness to participate, preoperative platelet count
      ⩽150 × 109/mm3, age <18 or >79 years, emergency procedure, redo surgery, a known coagulation
      disorder and inaccurate documentation of preoperative antiplatelet medication.

      Methods All patients were managed by the same surgical team and anaesthesiologist. They all
      received general anaesthesia in accordance with our institutional protocol. A dose of 15mg/kg
      tranexamic acid was given at induction of anaesthesia and after protamine administration.
      Surgery was performed under normothermia using a standard median sternotomy and MiECC modular
      (Type IV) circuit was used in all patients during CPB. An activated clotting time (ACT) value
      >300sec was aimed for patients undergoing CABG and an ACT>400sec for all other valve or
      complex surgery. Reversal of heparin was accomplished with protamine at a heparin-protamine
      titration ratio of 0.75.

      Preoperatively demographics, comorbidities, use of anticoagulants, antiplatelet medication
      were collected and intraoperatively type of operation, duration of CPB, duration of aortic
      cross-clamp, and heparin and protamine doses were recorded. Fibrinogen levels (mg/dL) were
      measured before surgery (baseline) and after arrival in the ICU. Postoperative bleeding at 12
      and 24 hours, as defined according to the universal definition of bleeding, was recorded, as
      well as intraoperative and 24-hour transfusion requirements (including blood products or
      coagulation factors concentrates) and major adverse events.

      Platelet aggregation was measured on two time points: T1 = arriving in operating room before
      any drug or fluid administration and T2' = 20 minutes after heparin reversal with protamine,
      in whole hirudin containing blood samples using the ROTEM platelet (TEM International GmbH,
      Munich, Germany), which evaluates impedance aggregometry. Specific reagents were chosen: 1.
      adenosine diphosphate (ADP) known as ADPtest to evaluate ADP function and thienopyridine
      efficiency, 2. thrombin receptor activating peptide (TRAP) known as TRAPtest assay for
      assessment of blockage of GPIIb/IIIa or protease-activated receptor (PAR). Abnormal values
      were indicative of platelet dysfunction. Regarding thromboelastometry, parameters that were
      recorded included the EXTEM and the FIBTEM assay. EXTEM and FIBTEM assays were performed at
      two time points: T1: before anaesthesia induction and fluid administration and T2: after
      removal of aortic cross clamp. Clotting time (CT) reflecting initiation of the clotting
      cascade and clot formation time (CFT) reflecting fibrin polymerization and clot stabilization
      were measured in EXTEM assay. Maximum clot firmness (MCF), indicating clot strength, was
      measured in EXTEM and FIBTEM assays.

      Statistical Analysis Plan The SPSS v.25.0 software (SPSS, Inc., Chicago, Ill, USA) was
      utilized for all statistical analyses. The significance level was set at p≤0.05 for the
      tested hypotheses. Continuous variables are presented as mean and standard deviation (SD).
      Categorical variables are expressed as absolute values and relative frequencies. Measures at
      the two time points were assessed for normality using the Kolmogorov Smirnov and Shapiro-Wilk
      tests and then analyzed with paired samples t-test or Wilcoxon U-test, as appropriate. For
      continuous variables, correlations were examined with Pearson or Spearman correlation
      according to the distribution of the data. Regression was performed for the primary outcome
      variables. A binary logistic regression model was used to estimate the multivariate
      predictive ability of perioperative variables on the primary outcome.
    

Intervention name(s): Thromboelastometry, Impedance Aggregometry
Intervention type(s): Diagnostic Test
Intervention description(s): Study of coagulation changes after cardiac surgery on CPB using Minimal Extracorporeal Circulation
Other intervention name(s): Rotational ThromboElastoMetry (ROTEM), ROTEM Platelet
Observational model: Cohort
Time perspective: Prospective
Sampling method: Probability Sample
Study population: 
        Patients presenting at AHEPA University Hospital for cardiac surgery
      
Keywords: extracorporeal circulation; coagulation disorder; Extracorporeal Circulation of Blood; Thrombocytopenia