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Risk factors of incomplete distribution of cardioplegic solution during coronary artery grafting
C Quintilio1, P Voci, F Bilotta
1Department of Cardiac Surgery, University of Florence, Italy.
Insights
Retrograde cardioplegia provides better myocardial opacification than antegrade in patients with poor coronary collateral circulation. However, retrograde offers no advantage when collateral circulation is well-developed during coronary artery bypass grafting.
Area of Science:
- Cardiology
- Cardiac Surgery
- Cardiovascular Research
Background:
- Myocardial protection during coronary artery bypass grafting (CABG) is crucial.
- Antegrade and retrograde cardioplegia delivery methods aim to optimize myocardial perfusion.
- The role of coronary collateral circulation in cardioplegia distribution remains an area of investigation.
Purpose of the Study:
- To assess myocardial distribution of cardioplegic solution using combined antegrade/retrograde routes.
- To compare the efficacy of antegrade versus retrograde cardioplegia in patients with varying degrees of coronary collateral circulation.
- To evaluate the impact of collateral circulation on myocardial opacification during CABG.
Main Methods:
- Myocardial contrast echocardiography was employed to assess cardioplegia distribution.
- 18 patients with chronic stable angina and three-vessel disease undergoing elective CABG were studied.
- Patients were categorized based on the presence of good or poor coronary collateral circulation.
Main Results:
- Overall myocardial opacification was significantly greater with retrograde than antegrade cardioplegia (77.7% vs. 59.1%, p=0.0009).
- In patients with poor collaterals, retrograde cardioplegia resulted in significantly greater opacification (81.2% vs. 44.3%, p<0.02).
- No significant difference in opacification was observed between antegrade and retrograde cardioplegia in patients with good collaterals.
Conclusions:
- Retrograde cardioplegia offers no advantage over antegrade delivery in patients with well-developed collateral circulation during CABG.
- Antegrade cardioplegia may be inadequate for myocardial protection in patients with poor collaterals and significant coronary artery disease.
- Retrograde delivery may be beneficial in specific patient subsets requiring enhanced myocardial protection.
Abstract:
Myocardial distribution of cardioplegic solution infused by combined antegrade/retrograde routes was assessed with myocardial contrast echocardiography in 18 patients with chronic stable angina and three-vessel disease undergoing elective coronary artery bypass grafting. Overall myocardial opacification was significantly greater in retrograde than in antegrade cardioplegia (77.7% +/- 13.4% versus 59.1% +/- 15.7%; p = 0.0009). The difference was affected by collateral circulation, as pointed out by the significant interaction between coronary collateral circulation and percent of myocardial opacification after antegrade and retrograde cardioplegia (p = 0.002). When we performed multiple comparisons, in patients with good collaterals the opacification difference between antegrade and retrograde cardioplegia was not statistically significant (66.4% +/- 10.2% versus 76.0% +/- 15.2%; p = not significant), whereas in patients with poor collaterals myocardial opacification during retrograde cardioplegia was significantly greater (44.3% +/- 15.0% versus 81.2% +/- 9.0%; p < 0.02). During antegrade cardioplegia, patients with poor collaterals showed a lower degree of myocardial opacification than patients with good collaterals (44.3% +/- 15.0% versus 66.4% +/- 10.2%; p < 0.01). Our results show that retrograde cardioplegia in patients undergoing elective coronary artery bypass grafting offers no advantage over antegrade cardioplegia when collateral circulation is well developed. On the other hand, conventional aortic root infusion may not provide adequate myocardial protection in the subset of patients with significantly narrowed or occluded coronary arteries and poor collaterals.