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Published on: April 25, 2014
Invasive Assessment of the Myocardial Microcirculation during Beating Heart Coronary Artery Bypass Grafting
Marcin Hellmann1, Jakub Piotrowski2, Mariusz Kaszubowski3
1Department of Cardiac Diagnostics, Medical University, 80-214 Gdansk, Poland.
Insights
Coronary artery bypass grafting (CABG) on a beating heart maintains myocardial microvascular perfusion, likely due to robust coronary collateral circulation, protecting against ischemia in advanced coronary artery disease.
Area of Science:
- Cardiovascular Surgery
- Cardiology
- Medical Technology
Background:
- Coronary artery bypass grafting (CABG) can lead to cardiac complications like ischemia.
- Well-developed coronary collateral circulation may mitigate these adverse effects.
- Assessing myocardial microvascular perfusion is crucial in beating heart surgery.
Purpose of the Study:
- To continuously assess myocardial microvascular perfusion during beating heart CABG.
- To evaluate the role of coronary collateral circulation in maintaining perfusion.
- To correlate perfusion changes with hemodynamic instability and ischemia.
Main Methods:
- Laser Doppler flowmetry used for continuous myocardial microvascular perfusion assessment.
- Study included consecutive patients undergoing CABG on a beating heart.
- Analysis of perfusion signals at baseline, during artery occlusion, and after reperfusion.
Main Results:
- No significant perfusion differences observed in most patients (n=42) during CABG.
- Significantly reduced perfusion noted in a subset (n=12) with hemodynamic instability and ischemia.
- Strong positive correlation found between high-sensitivity troponin I levels and perfusion decrease (r=0.854, p<0.001).
Conclusions:
- Myocardial microvascular perfusion remains stable during beating heart CABG in advanced coronary artery disease.
- Extensive coronary collateral circulation is the likely mechanism for maintained perfusion.
- Perfusion monitoring can identify patients at risk of ischemia during CABG.
Abstract:
Coronary artery bypass grafting may be associated with several cardiac complications, including ischemia, acute myocardial infarction, arrhythmias, or hemodynamic instability. Accumulating evidence suggests that well-developed coronary collateral circulation may protect against adverse effects, including myocardial ischemia. Assessment of myocardial microvascular perfusion is, therefore, of great clinical interest in beating heart surgery. In this paper, myocardial microvascular perfusion is continuously assessed on the beating heart using laser Doppler flowmetry in consecutive patients who underwent coronary artery bypass grafting procedures. No significant (p = 0.110) differences were found between the averaged perfusion signal (n = 42) at the baseline, during artery occlusion, or after reperfusion (732.4 ± 148.0 vs. 711.4 ± 144.1 vs. 737.0 ± 141.2, respectively). In contrast, significantly different (p < 0.001) mean perfusion signals (n = 12) were found (805.4 ± 200.1 vs. 577.2 ± 212.8 vs. 649.3 ± 220.8) in a subset of patients who presented with hemodynamic instability and myocardial ischemia. Additionally, a strong positive correlation between the plasma levels of high-sensitivity troponin I and perfusion decrease level after artery occlusion was found (r = 0.854, p < 0.001). This study argues that myocardial microvascular perfusion remains constant during coronary artery bypass grafting on the beating heart in advanced coronary artery disease. This phenomenon is most likely due to an extensive coronary collateral circulation.
