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Myocardial temperature mapping in patients with left main coronary artery disease
Insights
A new cardioplegia delivery method significantly reduced perioperative myocardial infarction (MI) and cardiac death in high-risk patients undergoing bypass surgery. This improved myocardial preservation technique involved temperature-guided grafting and adequate cardioplegia volumes.
Area of Science:
- Cardiovascular Surgery
- Cardiac Anesthesia
- Myocardial Protection
Background:
- High-risk patients undergoing aortocoronary bypass grafting require optimal myocardial protection.
- Previous methods of cardioplegia delivery may not ensure consistent myocardial preservation.
Purpose of the Study:
- To compare the efficacy of two different cardioplegia delivery methods in high-risk patients undergoing bypass grafting.
- To evaluate the impact on perioperative myocardial infarction (MI) and mortality.
Main Methods:
- Retrospective analysis of two consecutive patient groups undergoing bypass grafting.
- Group I: Pressure-regulated aortic root infusion with temperature-guided bypass sequence.
- Group II: Hand-held syringe delivery without temperature mapping.
Main Results:
- Group I (temperature-guided) had significantly lower perioperative MI (2% vs 13%, p<0.05).
- Group I showed a trend towards reduced cardiac mortality (2% vs 11%, p=0.09).
- Despite being older, Group I patients experienced better outcomes.
Conclusions:
- Adequate cardioplegia volume delivery is crucial for myocardial preservation.
- Myocardial temperature-directed bypass grafting enhances outcomes in high-risk cardiac surgery.
- The described method improves myocardial protection during bypass procedures.
Abstract:
Two consecutive groups of high risk patients with left main coronary disease (greater than 50% stenosis) undergoing aortocoronary bypass grafting using different cardioplegia delivery methods were compared retrospectively for perioperative myocardial infarction (MI) and mortality. Group I (July 1979 to June 30, 1982, n = 53) received an initial 1000 ml aortic root cardioplegia infusion from a pressure regulated (85-100 mmHg) delivery system. Regional mid-myocardial wall temperatures determined the distal anastomoses sequence (with the warmest region bypassed first) followed by additional 400 ml cardioplegia infusions. Group II patients (March 1976 to June 30, 1979, n = 47) had their cardioplegia administered by a hand-held syringe without regional temperature mapping. The volume injected varied and was based on cessation of electrical activity or a septal temperature less than 20 degrees C. Background data were similar except that Group I was significantly older than Group II (63.4 +/- 1.4 years vs 57.1 +/- 1.5 years, p less than 0.01). Despite this, there was only 1 (2%) perioperative MI in Group I vs 6 (13%) in Group II (p less than 0.05). There was also a marked reduction in cardiac mortality with 1 (2%) cardiac death in Group I vs 5 (11%) in Group II (p = 0.09). These data suggest that the delivery of adequate volumes of cardioplegia, in conjunction with myocardial temperature directed bypass grafting, can improve myocardial preservation in high risk patients.