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Assessment of myocardial perfusion during CABG surgery with two-dimensional transesophageal contrast echocardiography
S Aronson1, B K Lee, J G Wiencek
1Department of Anesthesia and Critical Care, University of Chicago Pritzker School of Medicine, Illinois.
Insights
This study introduces a new echocardiography method using contrast microbubbles to assess blood flow during coronary artery bypass graft (CABG) surgery, improving perfusion assessment and identifying potential issues.
Area of Science:
- Cardiovascular Surgery
- Medical Imaging
- Hemodynamics
Background:
- Assessing myocardial perfusion after coronary artery bypass graft (CABG) surgery lacks reliable quantitative methods.
- Current techniques do not provide real-time, detailed information on blood flow distribution during CABG.
Purpose of the Study:
- To evaluate the effectiveness of two-dimensional transesophageal contrast echocardiography (TEE) using microbubbles for assessing myocardial blood flow during CABG.
- To correlate intraoperative perfusion findings with postoperative cardiac function.
Main Methods:
- Utilized 2D TEE with sonicated Renografin-76 microbubbles in 15 patients undergoing CABG.
- Administered contrast via aortic root and direct injection into vein-CABG anastomosis.
- Acquired real-time echocardiographic images of the left ventricle short axis.
Main Results:
- TEE accurately visualized coronary artery-vein bypass run-off and identified poorly perfused myocardial regions.
- Intraoperative TEE perfusion patterns correctly predicted preoperative angiographic predictions 84% of the time.
- Detected perfusion deficits correlated with regional wall motion abnormalities post-bypass.
Conclusions:
- Contrast-enhanced TEE provides on-line visualization of myocardial blood flow changes before, during, and after CABG.
- This technique offers a quantifiable index for assessing CABG outcomes.
- Identified perfusion deficits can predict adverse postoperative cardiac function.
Abstract:
No reliable, quantifiable index of tissue perfusion is currently available to assess the efforts of coronary artery bypass graft (CABG) surgery. We used two-dimensional transesophageal contrast echocardiography with sonicated Renografin-76 microbubbles to determine the distribution of myocardial blood flow during coronary artery bypass graft surgery in 15 patients. Sonicated Renografin-76 contrast agent was injected into the aortic root of all patients after institution of cardiopulmonary bypass and application of the aortic occlusive clamp. Eight patients had contrast agent injected directly into the free proximal end of the vein-CABG anastomosis. All patients again received aortic root injections during reperfusion after anastomosis of the proximal aortovein and distal coronary artery. Echocardiographic images of the left ventricle short axis at the level of the papillary muscles were obtained in real time and analyzed retrospectively from videotape. Injection of contrast provided information about the magnitude and geometric distribution of coronary artery-vein bypass run-off and enabled identification of poorly perfused myocardial regions. When predicted myocardial perfusion patterns, based on preoperative evaluation of epicardial vessel distribution derived from coronary angiography, were compared to actual perfusion patterns assessed with intraoperative echocardiography, contrast regional myocardial perfusion patterns were predicted 84% of the time (71-97%, 95% confidence limit). Regional myocardial perfusion deficits detected after coronary bypass grafting were associated with regional wall motion abnormalities detected after separation from cardiopulmonary bypass. Our technique makes possible on-line visualization of changes in regional blood flow in the heart before, during, and after CABG.(ABSTRACT TRUNCATED AT 250 WORDS)