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Thrombin Generation in Cardiac Versus Noncardiac Surgical Cohorts
W Leif Ericksen1, Jerrold H Levy2, Ethan S Kim1
1From the Department of Anesthesiology, Stony Brook University, Stony Brook, New York.
Insights
Cardiac surgery patients show significantly reduced thrombin generation post-operation compared to non-cardiac surgery patients. This finding highlights potential differences in coagulation profiles after major surgical interventions.
Area of Science:
- Cardiovascular Surgery
- Hemostasis and Thrombosis
- Coagulation Assays
Background:
- Post-cardiac surgery bleeding is a significant concern, often delaying venous thromboembolism (VTE) prophylaxis or anticoagulation.
- The calibrated automated thrombin (CAT) generation assay is a gold standard for evaluating thrombin generation, a key factor in clot formation.
- Previous studies have not compared thrombin generation profiles between cardiac and non-cardiac surgical patients.
Purpose of the Study:
- To compare postoperative thrombin generation profiles in cardiac surgery patients versus non-cardiac surgery patients.
- To investigate potential differences in coagulation dynamics following different types of major surgery.
Main Methods:
- A prospective, observational cohort study involving 50 cardiac and 50 non-cardiac surgical patients.
- Blood samples were collected preoperatively and daily for four days postoperatively.
- Calibrated automated thrombin (CAT) generation assay was used to measure thrombin generation parameters.
Main Results:
- Cardiac surgical patients exhibited a 100% decrease in median endogenous thrombin potential (ETP), while non-cardiac patients showed only a 2% decrease (P < .001).
- All measured thrombin generation parameters were significantly depressed in the cardiac surgery group.
- Multivariable regression analysis indicated that cardiac surgical type was associated with a -76.5% difference in ETP change (95% CI, -87.4 to -65.5; P < .001).
Conclusions:
- Cardiac surgical patients experience a profound postoperative reduction in thrombin generation compared to non-cardiac surgical patients.
- Hemodilution and coagulation factor depletion are likely contributors to the observed decrease in thrombin generation after cardiac surgery.
Background:
Bleeding can be a significant problem after cardiac surgery. As a result, venous thromboembolism (VTE) or anticoagulation or both following mechanical valve implantation are often delayed in these patients. The calibrated automated thrombin (CAT) generation assay has become the gold standard to evaluate thrombin generation, a critical step in clot formation independent of other hemostatic processes (eg, platelet activation, fibrin cross-linking, and fibrinolysis), and is increasingly used to examine thrombotic and hemorrhagic outcomes. No study has currently used this assay to compare the thrombin generation profiles of cardiac surgical patients to noncardiac surgical patients. We hypothesize that noncardiac patients may be less prone to postoperative changes in thrombin generation.
Methods:
A prospective, observational, cohort study was undertaken using blood samples from 50 cardiac and 50 noncardiac surgical patients preoperatively, immediately postoperatively, and on postoperative days 1 to 4. Platelet-poor plasma samples were obtained from patients preoperatively, on arrival to the postanesthesia care unit (PACU) or intensive care unit (ICU), and daily on postoperative days 1 to 4 if patients remained inpatient. Samples were evaluated for CAT measurements. Patient and surgical procedure characteristics were obtained from the electronic medical record.
Results:
The primary outcome variable, median endogenous thrombin potential (ETP), measured in nanomolar × minutes (nM × min), was decreased 100% in cardiac surgical versus 2% in noncardiac patients (P < .001). All parameters of thrombin generation were similarly depressed. Cardiac (versus noncardiac) surgical type was associated with -76.5% difference of percent change in ETP on multivariable regression analysis (95% confidence interval [CI], -87.4 to -65.5; P value <.001).
Conclusions:
Cardiac surgical patients exhibit a profound decrease in thrombin generation postoperatively compared with noncardiac surgical patients evaluated by this study. Hemodilution and coagulation factor depletion likely contribute to this decreased thrombin generation after cardiac surgery.
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