Thrombin in Cardiac Surgery

Study Overview
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Brief Summary
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Coagulopathy, bleeding, and transfusion are common in cardiac surgical patients. Our collaborator has developed a novel point of care device that can be used to assess thrombin generation in real-time in cardiac surgical patients. The investigators will measure thrombin generation using our novel device and compare it to standard methods, while examining the association of thrombin parameters with bleeding and other clinical outcomes.

Detailed Description
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This is a prospective observational cohort study of 200 cardiac surgical patients. Thrombin generation via our novel point of care thrombin generation assay as well as calibrated automated thrombography (CAT) will be measured at three time points: (1) before surgery; (2) post-CPB after heparin reversal with protamine; (3) at the time of chest closure or 60 minutes after heparin reversal with protamine. Clinicians will remain blinded to the measures. Recruitment will continue until the investigators enroll 50 patients with significant impaired thrombin generation capacity (>50% drop from baseline) and 50 patients who receive hemostatic therapies. Patients will be followed for 7 days postoperatively to assess individual products transfused.

Official Title
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Diagnosis and Management of Impaired Thrombin Generation in Cardiac Surgery

Conditions
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Surgical Blood Loss, Coagulation Disorder, Thrombin, Hemostatic Disorder, Cardiovascular Surgical Procedures

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: -All adult patients (> 18 years of age) undergoing cardiac surgery at Toronto General Hospital will be offered participation. Exclusion Criteria: -Patients who are unable to consent to the study or who refuse participation will be excluded.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Cardiac Surgical Patients<br>All consenting adults undergoing cardiac surgery at Toronto General Hospital. | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Thrombin Generation, as assessed by the Endogenous Thrombin Potential (ETP) | The primary thrombin generation parameter of interest is the endogenous thrombin potential, or ETP, expressed in nM*min. The change in thrombin generation in patients undergoing cardiac surgery before and after cardiopulmonary bypass using our new point-of-care thrombin sensor and the established laboratory-based calibrated automated thrombogram (CAT) assay will be assessed. | The change in thrombin generation will be assessed from preoperative baseline up until 12 hours post-operatively | 
| Thrombin Generation, as assessed by the Lag Time | The co-primary thrombin generation parameter of interest is the Lag Time, expressed in seconds. The change in thrombin generation in patients undergoing cardiac surgery before and after cardiopulmonary bypass using our new point-of-care thrombin sensor and the established laboratory-based calibrated automated thrombogram (CAT) assay will be assessed. | The change in thrombin generation will be assessed from preoperative baseline up until 12 hours post-operatively | 
| Thrombin Generation, as assessed by the Time to Peak | The co-primary thrombin generation parameter of interest is the Time to Peak, expressed in seconds. The change in thrombin generation in patients undergoing cardiac surgery before and after cardiopulmonary bypass using our new point-of-care thrombin sensor and the established laboratory-based calibrated automated thrombogram (CAT) assay will be assessed. | The change in thrombin generation will be assessed from preoperative baseline up until 12 hours post-operatively | 
| Thrombin Generation, as assessed by the Peak Height | The co-primary thrombin generation parameter of interest is the Peak Height, expressed in nM. The change in thrombin generation in patients undergoing cardiac surgery before and after cardiopulmonary bypass using our new point-of-care thrombin sensor and the established laboratory-based calibrated automated thrombogram (CAT) assay will be assessed. | The change in thrombin generation will be assessed from preoperative baseline up until 12 hours post-operatively | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Total Units of Red Blood Cells Transfused | The total number of red blood cells units transfused will be recorded | From intra-operatively up to 12 hours post-operatively | 
| Total Units of Platelets Transfused | The total number of platelets units transfused will be recorded | From intra-operatively up to 12 hours post-operatively | 
| Total Units of Frozen Plasma Transfused | The total number of frozen plasma units transfused will be recorded | From intra-operatively up to 12 hours post-operatively | 
| Total amount of Prothrombin Complex Concentrates transfused | The total number of prothrombin complex concentrate units will be recorded | From intra-operatively up to 12 hours post-operatively | 
| Total amount of Fibrinogen Concentrate transfused | The total number of grams of fibrinogen concentrate transfused will be recorded | From intra-operatively up to 12 hours post-operatively |