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The relationship between immediate outcome after cardiac surgery, homogeneous cardioplegia delivery, and ejection
Insights
Contrast echocardiography can assess cardioplegia distribution during cardiac surgery. This method may help predict patient outcomes, especially for those with low ejection fraction, improving myocardial protection strategies.
Area of Science:
- Cardiology
- Cardiac Surgery
- Medical Imaging
Background:
- Optimal myocardial protection during cardiac surgery relies on homogeneous cardioplegia distribution.
- Contrast echocardiography can evaluate intramyocardial cardioplegia distribution.
Purpose of the Study:
- To test if cardioplegia distribution information from contrast echocardiography correlates with immediate clinical outcomes after cardiac surgery.
- To assess the utility of contrast echocardiography in stratifying patients based on intraoperative myocardial protection.
Main Methods:
- Retrospective analysis of 21 cardiac surgery patients.
- Transesophageal echocardiography (TEE) used to assess contrast-enhanced cardioplegia distribution in the left ventricle.
- Myocardial segments scored for contrast intensity (0-3) and averaged to generate antegrade, retrograde, and global scores.
Main Results:
- Patients separated from bypass without difficulty (Group A) had higher antegrade, retrograde, and global contrast scores than those requiring support (Group B).
- Preoperative ejection fraction was lower in Group B, but not always predictive of postoperative support needs.
- Low preoperative ejection fraction combined with low intraoperative contrast scores predicted the need for postoperative circulatory support.
Conclusions:
- Contrast echocardiography effectively evaluates cardioplegia delivery intensity and distribution, indicating myocardial protection efficacy.
- While low ejection fraction predicts poor outcomes, contrast echocardiography may refine patient stratification.
- Further prospective studies are warranted to confirm the relationship between contrast echocardiography findings and patient outcomes.
Background:
Optimal myocardial protection during cardiac surgery with ischemic arrest is predicated on among other variables, homogeneous cardioplegia distribution. Contrast echocardiography has been shown to provide information regarding the intramyocardial distribution of cardioplegia solution. To test the hypothesis that information regarding cardioplegia distribution derived from contrast echocardiography may be associated with immediate clinical outcome after cardiac surgery, data from 21 patients were examined retrospectively.
Methods:
Contrast-enhanced cardioplegia distribution patterns of the left ventricle short axis view obtained with transesophageal echocardiography were examined off-line by four observers blinded to clinical outcome. Contrast effect was scored for eight equally divided myocardial segments (0 = no contrast, 1 = nonuniform contrast, 2 = uniform contrast, 3 = excessive contrast). The scores were then averaged between segments and between observers to generate an antegrade, a retrograde, and a combined global contrast score for each patient.
Results:
Seventeen patients were separated from bypass without difficulty (group A) and 4 patients required sustained inotropic therapy or an intra-aortic balloon pump to facilitate separation from bypass (group B). As would be expected, group A patients had a higher average preoperative ejection fraction than did group B patients (60 percent +/- 14 vs 31 percent +/- 7, p < 0.01). In group A, however, for 4 of 17 patients (23 percent), low preoperative ejection fraction was not predictive of postoperative exogenous circulatory support requirements. Group A patients also had significantly higher antegrade (1.6 vs 1.2, p < 0.02), retrograde (1.7 vs 1.1, p < 0.02), and combined global contrast scores (1.7 vs 1.1, p < 0.01) than did group B patients. All patients with low preoperative ejection fraction and low intraoperative contrast scores required exogenous support to separate from cardiopulmonary bypass.
Conclusion:
Contrast echocardiography makes possible an evaluation of the intensity and distribution of contrast-enhanced cardioplegia delivery and we believe the efficacy of intraoperative myocardial protection. Although low preoperative ejection fraction is a known predictor of poor immediate postoperative outcome following cardiac surgery, not all patients with low preoperative ejection fractions require inotropic support postoperatively. Our results suggest that monitoring cardioplegia distribution with contrast echocardiography may offer insight for better patient stratification based on intraoperative myocardial protection in patients with low ejection fraction. We believe a more extensive evaluation of this relationship should be pursued in a prospective manner.