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Myocardial perfusion during warm antegrade and retrograde cardioplegia: a contrast echo study
M A Borger1, K S Wei, R D Weisel
1Division of Cardiovascular Surgery, Toronto General Hospital, Ontario, Canada.
Insights
Warm antegrade cardioplegia provides superior left ventricular perfusion compared to retrograde methods during coronary artery bypass grafting (CABG). Antegrade delivery also offers better right ventricular perfusion post-surgery.
Area of Science:
- Cardiovascular Surgery
- Cardiac Anesthesia
- Myocardial Protection
Background:
- Coronary artery bypass grafting (CABG) requires effective myocardial protection.
- Evaluating cardioplegia distribution is crucial for optimizing surgical outcomes.
Purpose of the Study:
- To compare the distribution and effectiveness of warm antegrade versus retrograde cardioplegia in CABG patients.
- To assess myocardial perfusion in the left ventricle (LV) and right ventricle (RV) using echocardiography.
Main Methods:
- Transesophageal echocardiography with microbubble contrast (Albunex) was used to evaluate myocardial perfusion.
- Perfusion was assessed pre- and post-CABG in segmented LV and RV territories.
- Contrast enhancement was quantitatively graded to determine perfusion levels.
Main Results:
- Antegrade cardioplegia achieved significantly higher LV perfusion (98% pre-CABG, 96% post-CABG) compared to retrograde (86% pre-CABG, 59% post-CABG).
- LV perfusion scores were consistently better with antegrade delivery (1.93 pre-CABG, 1.63 post-CABG) versus retrograde (1.53 pre-CABG, 1.19 post-CABG).
- Right ventricular perfusion was initially poor but improved with antegrade cardioplegia post-CABG.
Conclusions:
- Warm antegrade cardioplegia demonstrates superior left ventricular myocardial perfusion compared to warm retrograde cardioplegia.
- Antegrade delivery also provides better, though initially suboptimal, right ventricular perfusion post-CABG.
- Early construction of the saphenous vein graft to the right coronary artery is recommended for improved RV protection.
Background:
We evaluated distribution of warm antegrade and retrograde cardioplegia in patients undergoing coronary artery bypass grafting (CABG).
Methods:
Myocardial perfusion was evaluated pre- and post-CABG using transesophageal echocardiography with injection of sonicated albumin microbubbles (Albunex) during warm antegrade and retrograde cardioplegia. The left ventricle (LV) was evaluated in five segments and the right ventricle (RV) was evaluated in two segments. Segmental contrast enhancement was graded as absent (score = 0), suboptimal or weak (score = 1), optimal or excellent (score = 2), or excessive (score = 3).
Results:
Pre-CABG cardioplegic perfusion correlated weakly with severity of coronary artery stenoses (r = -0.331 and 0.276 for antegrade and retrograde cardioplegia, respectively). Antegrade cardioplegia administration resulted in 98% and 96% perfusion to the left ventricle pre- and post-CABG, respectively. Retrograde cardioplegic administration resulted in reduced LV perfusion, with 86% (p = 0.032 from antegrade) and 59% (p<0.001 from antegrade) pre- and post-CABG, respectively. The average LV perfusion score (mean +/- SEM) was greater with antegrade than retrograde cardioplegia both pre-CABG (1.93+/-0.04 vs. 1.53+/-0.11, p<0.001) and post-CABG (1.63+/-0.07 vs. 1.19+/-0.13, p = 0.004). RV perfusion was poor with both techniques pre-CABG, but improved significantly with antegrade cardioplegia post-CABG.
Conclusions:
We conclude that warm antegrade cardioplegia results in better left ventricular perfusion than warm retrograde cardioplegia. Right ventricular cardioplegic perfusion was suboptimal, but the best delivery was achieved with antegrade cardioplegia after coronary bypass. We therefore recommend construction of the saphenous vein graft to the right coronary artery early in the operative procedure.