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Hemodynamic effect of myocardial revascularization in the impaired ventricle
Insights
Myocardial revascularization significantly improved left ventricular performance in most patients with ischemic and abnormal ventricles. This highlights the importance of revascularization for impaired ventricles, especially when complete revascularization is achieved.
Area of Science:
- Cardiology
- Cardiac Surgery
- Cardiovascular Physiology
Background:
- Myocardial revascularization aims to improve blood flow to the heart muscle.
- Assessing the long-term hemodynamic effects of coronary artery bypass grafting (CABG) is crucial for patient outcomes.
- Patient stratification based on ventricular function (ejection fraction and LVEDP) is important for evaluating surgical impact.
Purpose of the Study:
- To analyze the 1-year hemodynamic effects of myocardial revascularization using saphenous vein grafts.
- To compare outcomes in patients with normal, ischemic, and abnormal ventricles.
- To determine the necessity of revascularization for impaired ventricles.
Main Methods:
- Prospective analysis of 111 patients undergoing CABG with saphenous vein grafts.
- Hemodynamic measurements (ejection fraction, LVEDP, cardiac index) taken preoperatively and 1 year postoperatively.
- Patients categorized into three groups based on preoperative ventricular function.
Main Results:
- Significant improvement in cardiac index and LVEDP observed in patients with ischemic and abnormal ventricles.
- 89% of patients with ischemic ventricles showed unchanged or improved ejection fraction.
- Significant improvements in ejection fraction and cardiac index were noted in the abnormal ventricles group.
- Postoperative improvements were significant in 67% of patients with preoperative treadmill data.
Conclusions:
- Myocardial revascularization significantly enhances left ventricular performance, particularly in patients with ischemic and abnormal ventricles.
- Incomplete revascularization or inadequate myocardial protection may explain suboptimal outcomes in some studies.
- These findings support the necessity of revascularization for patients with impaired ventricular function.
Abstract:
The hemodynamic effect of myocardial revascularization with saphenous vein grafts (mean 3.3 per patient) was analyzed 1 year after operation in 111 patients. Operations were performed using one continuous period of aortic cross-clamping with hyperkalemic cardioplegia for distal anastomoses in 84% of patients; 16% had arrest with topical and systemic hypothermia for myocardial protection. Group I (N = 18) had normal ventricles (ejection fraction [EF] greater than 50%; left ventricular end-diastolic pressure [LVEDP] less than or equal to 12 torr); Group II (N = 64) had ischemic ventricles (EF greater than 50%, LVEDP greater than 13 torr); and Group III (N = 30) had abnormal ventricles (EF less than 50%, LVEDP greater than 13 torr). Hemodynamic measurements were obtained before and 1 year after operation. Fifteen of 18 patients (83%) in Group I did not show significant hemodynamic changes, but in three EF decreased by greater than or equal to 10% and LVEDP increased by greater than 10% over preoperative levels. In Group II, EF was unchanged or slightly better in 89% (57/64) and worse in seven patients. Improvement in cardiac index (p less than 0.01) and LVEDP (p less than 0.001) was significant. Worsening of EF in 10 of 82 patients in Groups I and II was attributed to graft closure and/or poor myocardial protection. In Group III, significant improvement in cardiac index (p less than 0.001), EF (p less than 0.001), and LVEDP (p less than 0.01) was also noted. A subset of nine patients with EF less than or equal to 35% showed postoperative improvement in 56%. Of the remaining 20 patients with an EF of greater than 35% to less than 50%, half had greater than or equal to 20% improvement in postoperative EF. Operative mortality was 3.3% (1/30) for Group III. Late mortality was 1.5% (1/64) for Group II and 10% (3/29) for Group III. Significant improvement was noted postoperatively in 67% (57/85) of all patients who had preoperative treadmill tests (p less than 0.001). This study shows that myocardial revascularization significantly improved left ventricular performance in most patients with ischemic and abnormal ventricles. Previous studies that fail to show improvement may be related to incomplete revascularization and/or poor myocardial preservation. These data, therefore, justify the need for revascularization of the impaired ventricle.