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Updated: Apr 28, 2026
In vitro Assessment of Myocardial Protection following Hypothermia-Preconditioning in a Human Cardiac Myocytes Model
Published on: October 27, 2020
Analysis of myocardial temperature changes in conventional isolated coronary artery bypass grafting
Hiroshi Okamoto1, Akinori Tamenishi, Toshihiko Nishi
1Department of Thoracic and Cardiovascular Surgery, Yokkaichi Municipal Hospital, Shibata, Yokkaichi, 2-2-37, Japan, cvsokamoto@yokkaichihp01.jp.
Insights
Cold blood cardioplegia (CBCP) effectively cools the heart, but its efficacy diminishes with severe coronary artery lesions, particularly in the left anterior descending artery. Retrograde delivery can supplement antegrade delivery for improved myocardial protection.
Area of Science:
- Cardiovascular Surgery
- Cardiac Anesthesia
- Myocardial Protection
Background:
- Assessing the efficacy of cold blood cardioplegia (CBCP) in overcoming coronary artery lesions.
- Analyzing the relationship between myocardial temperature changes and coronary artery lesion severity.
Purpose of the Study:
- To investigate the impact of coronary artery lesion severity on myocardial temperature distribution during cold blood cardioplegia.
- To evaluate the effectiveness of antegrade versus retrograde cardioplegia delivery in relation to lesion severity.
Main Methods:
- Measured myocardial temperature before and after antegrade and retrograde CBCP delivery in 492 coronary artery bypass grafting patients.
- Classified coronary artery stenosis severity into four grades (0-3) based on preoperative coronary arteriography.
- Analyzed the correlation between myocardial temperature changes and coronary artery lesion severity.
Main Results:
- Antegrade delivery showed reduced effectiveness with increasing stenosis severity, particularly in the left anterior descending (LAD) artery (p=0.0042).
- Mean antegrade temperature change in the LAD decreased significantly with higher lesion grades (9.7°C for grade 0 to 6.0°C for grade 3).
- Retrograde delivery demonstrated a significant inverse correlation with antegrade delivery, suggesting a complementary role (p<0.001).
Conclusions:
- Antegrade CBCP delivery is less effective in severe proximal coronary artery lesions, especially in the LAD territory.
- Retrograde cardioplegia delivery effectively supplements antegrade delivery, enhancing myocardial protection.
- Myocardial temperature monitoring is crucial for managing inadequate cardioplegic delivery and serves as a reliable indicator of myocardial protection.
Backgrounds:
To determine whether cold blood cardioplegia (CBCP) can get over coronary artery lesions, we analyzed the relationship between myocardial temperature changes and lesion severity of major coronary arteries.
Methods And Results:
From April 1991 to October 2003, we measured myocardial temperature before and after antegrade and retrograde delivery of CBCP in 492 patients undergoing conventional coronary artery bypass grafting. Stenotic severity of three major coronary arteries was classified into four grades according to preoperative coronary arteriography; grade 0 for 50 % or less, 1 for 75 %, 2 for 90 %, 3 for 99 % or 100 %. We analyzed relationships between myocardial temperature changes [ΔT-A (antegrade) & ΔT-R (retrograde)] and the coronary artery lesion's severity. Average ΔT-A of the right coronary artery had no relationship with stenotic grades. Mean ΔT-A of the left anterior descending (LAD) became less and less in proportion to its stenotic grade [9.7 °C for grade 0, 8.2 °C for grade 1, 7.1 °C for grade 2, and 6.0 °C for grade 3, respectively, (p = 0.0042)]. ΔT-A of the circumflex artery showed similar but weaker tendency than those of LAD. Significant inverse correlations were found between ΔT-A and ΔT-R1 in each territory (p < 0.001).
Conclusions:
Antegrade delivery was less effective in situations with tight proximal lesion, especially in the LAD territory. Retrograde delivery supplemented antegrade delivery. Myocardial temperature monitoring enables us to deal with inadequate cardioplegic delivery, and is a good indicator of myocardial protection.
