Myocardial Metabolism Altered by Ischemic Preconditioning and Enflurane in Off-Pump Coronary Artery Surgery

Drenger, Benjamin; Gilon, Dan; Chevion, Mordechai; Elami, Amir; Meroz, Yuval; Milgalter, Eli; Gozal, Yaacov

doi:10.1053/j.jvca.2007.12.023

« Previous Next »Journal of Cardiothoracic and Vascular Anesthesia
Volume 22, Issue 3 , Pages 369-376, June 2008

Myocardial Metabolism Altered by Ischemic Preconditioning and Enflurane in Off-Pump Coronary Artery Surgery

Benjamin Drenger, MD
- Department of Anesthesiology and Critical Care Medicine, Hadassah–Hebrew University Medical Center Hospital and the Hebrew University School of Medicine, Jerusalem, Israel
- Address reprint requests to Benjamin Drenger, MD, Department of Anesthesiology and Critical Care Medicine, Hadassah University Hospital, PO Box 24035, Jerusalem 91240, Israel.
Dan Gilon, MD
- Department of Cardiology, Hadassah–Hebrew University Medical Center Hospital and the Hebrew University School of Medicine, Jerusalem, Israel
Mordechai Chevion, PhD
- Department of Cellular Biochemistry, Hadassah–Hebrew University Medical Center Hospital and the Hebrew University School of Medicine, Jerusalem, Israel
Amir Elami, MD
- Department of Cardiac Surgery, Hadassah–Hebrew University Medical Center Hospital and the Hebrew University School of Medicine, Jerusalem, Israel.
Yuval Meroz, MD
- Department of Anesthesiology and Critical Care Medicine, Hadassah–Hebrew University Medical Center Hospital and the Hebrew University School of Medicine, Jerusalem, Israel
Eli Milgalter, MD
- Department of Cardiac Surgery, Hadassah–Hebrew University Medical Center Hospital and the Hebrew University School of Medicine, Jerusalem, Israel.
Yaacov Gozal, MD
- Department of Anesthesiology and Critical Care Medicine, Hadassah–Hebrew University Medical Center Hospital and the Hebrew University School of Medicine, Jerusalem, Israel

published online 25 March 2008.

Objective: During off-pump coronary artery bypass (OPCAB) surgery, the heart is subjected to ischemia and reperfusion. The authors hypothesized that the volatile anesthetics are as effective as ischemic preconditioning (IPC) in preserving myocardial function during off-pump cardiac surgery, and this effect is because of multiple mechanisms of action. Therefore, the effects of enflurane with its calcium inhibition and antioxidative properties were compared with mechanical IPC in preserving myocardial cellular markers.

Design: A prospective, randomized, controlled, and partly blinded study.

Setting: A tertiary care university hospital.

Participants: Twenty-five patients undergoing elective single-graft OPCAB surgery.

Interventions: Patients were randomized into 3 groups: (1) control (n = 8), (2) a single 5-minute ischemia/reperfusion interval of IPC before coronary occlusion (n = 9), and (3) 1.6% enflurane anesthesia 15 minutes before and during graft attachment (n = 8). Arterial and coronary sinus venous blood were analyzed for biochemical indices of ischemia and hydroxyl radical generation.

Measurements and Main Results: Although the hemodynamic changes were small, myocardial lactate production in the control group increased by 120%, whereas in the enflurane group it decreased significantly (p < 0.01) compared with the control and IPC groups. Oxygen utilization in the control group was 44% higher (p < 0.03), and there was also a larger release of the hydroxyl radical-dependent adduct 2,3-dihydroxybenzoic acid (225% increase, p < 0.05) compared with both study groups. During reperfusion, initial anterior wall hypokinesis by TEE was observed, with slow recovery during reperfusion compared with early recovery in both study groups.

Conclusions: Coronary occlusion during OPCAB surgery results in increased production of ischemia-related metabolic products. The application of methods such as IPC or volatile anesthesia appears to reduce the metabolic deficit, free-radical production, and physiologic changes.

Key words: heart, myocardial protection, ischemic preconditioning, volatile anesthetics, enflurane, coronary artery bypass graft surgery, off-pump coronary artery bypass, free radicals, hydroxyl radicals