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Updated: Jul 20, 2025
Evaluation of Coronary Flow Reserve After Myocardial Ischemia Reperfusion in Rats
Published on: June 28, 2019
Coronary artery bypass grafting transiently improves myocardial flow reserve in patients with impaired left
Shuhei Nishijima1, Michinobu Nagao2, Atsushi Yamamoto2
1Department of Cardiovascular Surgery, Tokyo Women's Medical University, Tokyo, Japan.
Insights
Coronary artery bypass grafting (CABG) significantly improves myocardial flow reserve (MFR) in patients with coronary artery disease (CAD) and left ventricular dysfunction. This indicates CABG rapidly restores microcirculatory function.
Area of Science:
- Cardiology
- Nuclear Medicine
- Cardiovascular Surgery
Background:
- Myocardial flow reserve (MFR) assessed by 13N-ammonia positron emission tomography is crucial for evaluating ischemic cardiomyopathy and predicting prognosis in coronary artery disease (CAD).
- Short-term changes in MFR following coronary artery bypass grafting (CABG) require further elucidation.
- Comparative analysis with percutaneous coronary intervention (PCI) and optimal medical therapy (OMT) provides context for CABG outcomes.
Purpose of the Study:
- To evaluate the short-term impact of CABG on MFR in patients with CAD and left ventricular dysfunction.
- To assess changes in myocardial blood flow (MBF) and MFR before and after CABG.
- To provide reference data on MFR changes in PCI and OMT groups.
Main Methods:
- Measurement of myocardial blood flow (MBF) and MFR using 13N-ammonia positron emission tomography.
- Assessment of MFR and MBF in patients before and after CABG.
- Comparison of MFR and MBF changes in CABG, PCI, and OMT patient cohorts.
Main Results:
- Resting MBF showed no significant change post-CABG (0.84 ± 0.32 vs. 0.83 ± 0.23, P=0.958).
- Stress MBF significantly increased post-CABG (1.23 ± 0.64 vs. 1.49 ± 0.42, P < 0.001).
- Global MFR significantly improved post-CABG (1.49 ± 0.42 vs. 1.91 ± 0.51 mL/g/min, P < 0.001), alongside significant increases in stress and resting ejection fraction.
Conclusions:
- CABG leads to significant short-term improvements in MFR for patients with left ventricular dysfunction and CAD.
- Restoration of epicardial coronary artery patency effectively addresses short-term myocardial microcirculatory dysfunction.
- These findings highlight the rapid benefits of CABG on myocardial perfusion and function.
Background:
Myocardial flow reserve (MFR) derived from 13N-ammonia positron emission tomography is an index used to evaluate ischemic cardiomyopathy and predict the prognosis of patients with coronary artery disease (CAD). This study aimed to evaluate the short-term changes in MFR in patients who underwent coronary artery bypass grafting (CABG). In addition, as a reference, we showed the changes in MFR in the percutaneous coronary intervention (PCI) and optimal medical therapy (OMT) patient groups.
Methods:
To determine the short-term effects of CABG in CAD with left ventricular dysfunction, myocardial blood flow (MBF) and MFR were measured before and after CABG. Additionally, we showed changes in MBF and MFR of the PCI and OMT patient groups during treatment.
Results:
We observed that resting MBF did not significantly increase from baseline to post-CABG (0.84 ± 0.32 vs. 0.83 ± 0.23, P = 0.958); however, stress MBF increased significantly from baseline to post-CABG (1.23 ± 0.64 vs. 1.49 ± 0.42, P < 0.001). The global MFR increased significantly from baseline to post-CABG (1.49 ± 0.42 mL/g/min vs. 1.91 ± 0.51 mL/g/min, P < 0.001). Additionally, stress and resting ejection fraction (EF) significantly increased (stress EF: 42 ± 18.7% vs. 50.9 ± 18%, P = 0.005; resting EF: 45.8 ± 19.5% vs. 52.1 ± 19.4%, P = 0.031).
Conclusions:
This study demonstrated that CABG significantly improved MFR in a short period of time with left ventricular dysfunction. These findings suggest that epicardial coronary artery patency restores myocardial microcirculatory dysfunction in the short term.
