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Coronary bypass with substrate-enhanced cardioplegia versus non-cardioplegic technique for early revascularization in
L I Bonchek1, M W Burlingame, B E Vazales
1Division of Cardiothoracic Surgery, Lancaster General Hospital, PA.
Insights
Substrate enhanced cardioplegia (SECP) may improve early heart function after acute infarction revascularization. However, lasting benefits were not observed, and the internal mammary artery (IMA) without SECP is preferred for stable patients.
Area of Science:
- Cardiology
- Cardiac Surgery
- Myocardial Protection
Background:
- Acute myocardial infarction requires timely revascularization.
- Cardioplegia techniques aim to protect the heart during surgery.
- Substrate enhanced cardioplegia (SECP) is a specific method for myocardial protection.
Purpose of the Study:
- To compare the efficacy of substrate enhanced cardioplegia (SECP) versus noncardioplegic technique (NCP) in patients undergoing early revascularization for acute myocardial infarction.
- To evaluate early postoperative myocardial performance and clinical outcomes.
Main Methods:
- Randomized controlled trial comparing SECP (n=9) and NCP (n=9) groups.
- Patients underwent early revascularization (less than 4 hours).
- Preoperative, intraoperative, and postoperative parameters were assessed, including ejection fraction and cardiac enzyme levels.
Main Results:
- No significant preoperative differences between groups in age, sex, ejection fraction, or diseased vessels.
- Intraoperative aortic clamp times were significantly shorter in the NCP group (11 min vs. 38 min).
- Postoperative CPK-MB levels, inotrope use, and intra-aortic balloon pump duration were not significantly different, though trends favored SECP.
Conclusions:
- SECP may offer improved early myocardial performance post-revascularization.
- Lasting benefits of SECP were not evident in this early revascularization cohort.
- Internal mammary artery (IMA) grafting without SECP is recommended for stable, younger patients undergoing early revascularization due to its long-term survival benefits and ease of use.
Abstract:
Nine patients chosen at random received substrate enhanced cardioplegia (SECP) for early (less than 4 h) revascularization in acute infarction. A control group of 9 patients with similar clinical characteristics was chosen from the larger group revascularized concurrently with a noncardioplegic technique (NCP). There were no significant differences between the NCP and SECP groups respectively in preoperative clinical parameters such as age (62.8 vs. 62.3 years), sex (7 men, 2 women in both groups), ejection fraction (50% vs. 56%) or number of diseased vessels (2.1 vs 2.3). Intraoperative aortic clamp times were significantly shorter in NCP patients (11 vs. 38 min), and 4 NCP patients had no clamping. The internal mammary artery (IMA) was used in 6 NCP patients and 1 SECP patient (to a nonoccluded branch vessel). Postoperatively, NCP patients had higher peak CPK-MB (284 vs. 190 IU/l), longer use of inotropes (10 vs. 2.7 h) and intraaortic balloon pump (15 vs. 8 h), and a higher ejection fraction before discharge from hospital, but none of these differences were significant. SECP appears to provide better myocardial performance early postoperatively, but lasting benefits were not apparent in this subset of patients with early revascularization. Because the IMA has a powerful effect on long term survival but is very difficult to use with antegrade SECP, we continue to favor the IMA without SECP in hemodynamically stable, young patients (less than 65 years) who are revascularized early after infarction.