Invasive Assessment of the Myocardial Microcirculation during Beating Heart Coronary Artery Bypass Grafting

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.

Sirt1 ameliorated cardiac autophagic flux blockage via Prx2 during myocardial ischemia/reperfusion injury

“…Myocardial ischemia can cause myocardial brosis, myocardial hypertrophy and other compensatory reactions [1], and the long-term myocardial ischemia can even lead to heart failure [2]. Clinically, coronary artery bypass, angioplasty and other non-pharmacological strategies are often used for blood ow reperfusion to relieve myocardial ischemia [3]. However, the reperfusion after ischemia could aggravate myocardial structural and functional damage, which is called myocardial ischemia/reperfusion (MI/R) injury.…”