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Updated: Aug 16, 2026
Surgical Porcine Model of Chronic Myocardial Ischemia Treated by Exosome-laden Collagen Patch and Off-pump Coronary Artery Bypass Graft
Published on: September 15, 2023
Hemodilution and surgical hemostasis contribute significantly to transfusion requirements in patients undergoing
Sandra Dial1, Eugene Delabays, Martin Albert
1Department of Critical Care, SMBD Jewish General Hospital, McGill University, Montreal, Quebec, Canada. sandra.dial@mcgill.ca
Insights
Risk factors for low intraoperative hematocrit and excessive bleeding after coronary artery bypass grafting differ. Managing these requires limiting hemodilution and ensuring surgical hemostasis.
Area of Science:
- Cardiovascular Surgery
- Anesthesiology
- Hematology
Background:
- Low intraoperative hematocrit and excessive postoperative bleeding are potential complications in coronary artery bypass grafting (CABG).
- Identifying distinct risk factors for these two adverse events is crucial for improving patient outcomes.
Purpose of the Study:
- To determine the incidence and risk factors for low intraoperative hematocrit levels.
- To identify the incidence and risk factors for excessive postoperative bleeding.
- To assess whether these risk factors are the same and their impact on blood product transfusions.
Main Methods:
- Prospective cohort study of 613 adult patients undergoing CABG.
- Data collected from October 2000 to March 2001 across three tertiary university-affiliated hospitals.
- Multivariate analysis used to identify independent risk factors.
Main Results:
- Low intraoperative hematocrit (<19%) occurred in 24% of on-pump vs. 4% of off-pump procedures.
- Risk factors for low hematocrit included older age, female sex, lower preoperative hemoglobin, and longer bypass times.
- Excessive postoperative hemorrhage (>1 L) occurred in 26% of on-pump and 25% of off-pump patients, associated with male sex and longer pump times, but not low hematocrit.
Conclusions:
- Risk factors for low intraoperative hematocrit and excessive postoperative bleeding are distinct.
- Strategies to reduce these complications should focus on limiting hemodilution, especially in at-risk female patients.
- Careful surgical hemostasis is essential for minimizing postoperative bleeding.
Objective:
We sought to determine the incidence of and risk factors for the development of low intraoperative hematocrit levels and of excessive postoperative bleeding in patients undergoing coronary artery bypass grafting, whether the risk factors are the same, and their effect on blood product transfusions.
Methods:
We performed a prospective cohort study of 613 adult patients who underwent coronary artery bypass grafting in 3 tertiary, university-affiliated hospitals during the period from October 1, 2000, to March 31, 2001.
Results:
Low intraoperative hematocrit levels (<19%) were found in 131 (24%) patients who had operations performed with extracorporeal circulation compared with in 3 (4%) patients with operations performed off pump. In multivariate analysis this was associated with older age, female sex, lower preoperative hemoglobin levels, lower body surface area, longer duration on bypass, and use of higher total volumes with more hydroxyethyl starch in the circuit. Low intraoperative hematocrit levels did not predict excessive postoperative hemorrhage (>1 L of mediastinal drainage in the first 12 hours). This occurred in 26% (n = 140) of patients undergoing on-pump operations and in 25% of patients undergoing off-pump operations and in multivariate analysis was associated with male sex, longer pump times, not receiving aprotinin, and operations performed by certain surgeons but not with total circuit or hydroxyethyl starch volume.
Conclusions:
We observed that the risk factors for the development of a low intraoperative hematocrit level and excessive postoperative bleeding differed. Our results suggest that decreasing these outcomes in patients undergoing cardiac surgery requires a comprehensive approach, including limiting hemodilution, particularly in female subjects with lower preoperative hemoglobin levels, and careful attention to surgical hemostasis.
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