Heparin Based on Ideal Body Weight for Cardiopulmonary Bypass in Obese Patients

Study Overview
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Brief Summary
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The optimal heparin regimen during cardiopulmonary bypass (CPB) has not been well established in obese patients. Results of a preview study show that the standard heparin management based on total body weight in obese patients during CPB resulted in excessive heparin level, which could lead to excessive postoperative bleeding. To avoid this overdosing, an initial heparin bolus based on ideal body weight in obese patients was proposed. The main objective of the study is to evaluate the effects of heparin injection, based on ideal body weight, on intraoperative plasma heparin levels and activated coagulation time (ACT) in a population of obese patients, compared to a group of obese patients undergoing CPB surgery with heparin management based of total body weight. The secondary objectives are to evaluate the relationship between heparin level and ACT in each group of patients and at different time points during CPB, and to compare the incidence of bleeding, intraoperative transfusions and complications in the two groups of patients.

Official Title
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Heparin Management for Cardiopulmonary Bypass in Cardiac Surgery: A Prospective, Comparative and Randomized Study Evaluating a Dosage Based on the Ideal Body Weight in Obese Patients

Conditions
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Cardiac Surgery, Cardiopulmonary Bypass, Obese Patients (BMI ≥ 30 kg/m²)

Intervention / Treatment
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* Drug: Heparin, IV route, based on patients body weights (UI/kg)
* Procedure: Cardiopulmonary bypass
* Drug: Protamin administration


Participation Criteria
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Eligibility Criteria
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Inclusion criteria: Obese patients (BMI ≥ 30 kg/m²) Planned cardiac surgery under cardiopulmonary bypass Coronary-artery bypass graft, or valve surgery) Age ≥ 18 yo Exclusion criteria: Allergy to heparin Emergency surgical intervention Redo surgery Heart transplantation Surgery for circulatory assistance Pre-operative heparin use

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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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Intervention group<br>Obese patients, randomized to receive an initial IV bolus of Heparin, before beginning of the cardiopulmonary bypass, at the dosage of 340 UI/kg based on ideal body weight of the obese patients. The objective is to obtain an ACT target ≥ 400 s before the beginning of CPB. If necessary, additional boluses of heparin are administered at the dose of 100 UI/kg based on ideal body weight, to maintain this target during the CPB. | Drug: Heparin, IV route, based on patients body weights (UI/kg)<br> <br> Procedure: Cardiopulmonary bypass<br> <br> Drug: Protamin administration<br> <br> |
| Active Comparator: Control group<br>Obese patients, randomized to receive an initial IV bolus of Heparin, before beginning of the cardiopulmonary bypass, at the usual dosage of 300 UI/kg based on total body weight of the obese patients. The objective is to obtain an ACT target ≥ 400 s before the beginning of CPB. If necessary, additional boluses of heparin are administered at the dose of 100 UI/kg based on total body weight, to maintain this target during the CPB. | Drug: Heparin, IV route, based on patients body weights (UI/kg)<br> <br> Procedure: Cardiopulmonary bypass<br> <br> Drug: Protamin administration<br> <br> |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Plasma heparin level (anti-Xa activity, in UI/ml) |  | at 3 minutes after the first heparin injection | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Activated Clotting Time |  | during the intervention | 
| Plasma Antithrombin III level |  | during the intervention at 3 minutes after heparin injection (=T1) | 
| numbers of labile blood products transfused |  | during the surgery and the first 24 hours in ICU | 
| Postoperative bleedings |  | during the first 24 hours in ICU, based on chest tube outputs |