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Composite arterial Y graft has less coronary flow reserve than independent grafts
Genichi Sakaguchi1, Eiji Tadamura, Motoaki Ohnaka
1Department of Cardiovascular Surgery, Graduate School of Medicine, Kyoto University, Japan.
Insights
Arterial composite Y grafts improve resting myocardial blood flow but show reduced coronary flow reserve compared to independent grafts after coronary artery bypass surgery. This suggests independent grafts may offer better long-term flow dynamics.
Area of Science:
- Cardiovascular Surgery
- Cardiac Physiology
- Medical Imaging
Background:
- Assessing the efficacy of composite Y grafts versus independent arterial grafts for left coronary system revascularization.
- Investigating the adequacy of blood flow provided by composite Y grafts of the left internal thoracic artery.
Purpose of the Study:
- To compare regional myocardial blood flow (MBF) and coronary flow reserve (CFR) after coronary artery bypass grafting (CABG).
- To evaluate the performance of arterial composite Y grafts versus independent arterial grafts.
Main Methods:
- Positron emission tomography (PET) with oxygen-15-labeled water was used to measure regional MBF at rest and during hyperemia (dipyridamole infusion).
- Coronary flow reserve was calculated as the ratio of hyperemic to resting MBF in seven left ventricular segments.
- Two groups were studied: Y graft (n=22) and independent grafts (n=13).
Main Results:
- No significant difference in resting MBF between the Y graft and independent graft groups.
- Significantly lower coronary flow reserve in the Y graft group compared to the independent group in multiple regions (anterobasal, apical, septal, lateral).
- Specific CFR values were lower in the Y graft group across all assessed regions (p < 0.05).
Conclusions:
- Arterial composite Y grafts enhance resting myocardial blood flow but are less effective than independent grafts in improving coronary flow reserve post-CABG.
- Independent arterial grafts demonstrate superior coronary flow reserve capacity in the early postoperative period.
Background:
It is not known whether a composite Y graft of the left internal thoracic artery can provide sufficient blood flow to the whole left coronary system. The aim of this study was to compare regional myocardial blood flow (MBF) and coronary flow reserve after coronary artery bypass grafting using arterial composite Y graft or independent arterial grafts.
Methods:
Positron emission tomography was performed at rest and after dipyridamole infusion using oxygen-15-labeled water 2 weeks after coronary artery bypass grafting. Regional MBF was calculated in seven segments of the left ventricle. Coronary flow reserve was defined as the ratio of MBF after dipyridamole infusion to MBF at rest. In the Y graft group (n = 22), a free arterial graft to obtuse marginal arteries was anastomosed to the proximal side of in situ left internal thoracic artery, which was anastomosed to the left anterior descending artery. In the independent graft group (n = 13), left anterior descending and obtuse marginal arteries were independently revascularized using in situ left internal thoracic artery and a free arterial graft.
Results:
There was no difference between the groups in MBF at rest. Coronary flow reserve in the Y graft group was lower than that in the independent group in the anterobasal (1.43 +/- 0.07 versus 1.90 +/- 0.13, p = 0.038), apical (1.24 +/- 0.06 versus 1.64 +/- 0.12, p = 0.003), septal (1.34 +/- 0.05 versus 1.75 +/- 0.13, p = 0.023), and lateral regions (1.19 +/- 0.04 versus 1.66 +/- 0.09, p = 0.001).
Conclusions:
Although arterial composite Y graft improved MBF at rest, it was not as effective as independent grafts for improving coronary flow reserve soon after coronary artery bypass grafting.