Myocardial protection during elective coronary artery bypasses grafting by pretreatment with omega-3 polyunsaturated fatty acids
Authors: Veljovic Milic , Popadic Ana , Vukic Zoran , Ilic Radoje , Trifunovic Zoran , Antunovic Mirjana , Mandaric Vladimir , Tisma Svetislav , Markovic Zoran 
Published: May 2013

Background/Aim. Despite recent advances in coronary artery bypass grafting
(CABG), cardioplegic cardiac arrest and cardiopulmonary bypass (CPB) are
still associated with myocardial injury. Accordingly, the efforts have been
made lately to improve the outcome of CPB by glucose-insulinpotassium,
adenosine, Ca2+-channel antagonists, L-arginine, N-acetylcysteine, coenzyme
Q10, diazoxide, Na+/H+ exchange inhibitors, but with an unequal results.
Since omega-3 polyunsatutated fatty acids (PUFAs) have shown remarkable
cardioprotection in preclinical researches, the aim of our study was to check
their effects in prevention of ischemia reperfusion injury in patients with
CPB. Methods. This prospective, randomized, placebo-controlled study was
performed with parallel groups. The patients undergoing elective CABG were
randomized to receive preoperative intravenous omega-3 PUFAs infusion (n =
20) or the same volume of 0.9% saline solution infusion (n = 20). Blood
samples were collected simultaneously from the radial artery and the coronary
sinus before starting CPB and at 10, 20 and 30 min after the release of the
aortic cross clamp. Lactate extraction/excretion and myocardial oxygen
extraction were calculated and compared between the two groups. The levels of
troponin I (TnT) and creatine kinase-myocardial band (CK-MB) were determined
before starting CPB and 4 and 24 h postoperatively. Results. Demographic and
operative characteristics, including CPB and aortic cross-clamp time, were
similar between the two groups of patients. The level of lactate extraction
10 and 20 min after aortic cross-clamp time has shown negative values in the
control group, but positive values in the PUFAs group with statistically
significant differences (-19.6% vs 7.9%; p < 0.0001 and -19.9% vs 8.2%; p <
0.0008, respectively). The level of lactate extraction 30 minutes after
reperfusion was not statistically different between the two groups (6.9% vs
4.2%; p < 0.54). Oxygen extraction in the PUFAs group was statistically
significantly higher compared to the control group after 10, 20 and 30 min of
reperfusion (35.5% vs 50.4%, p < 0.0004; 25.8 % vs 48.7%, p < 0.0001 and
25.8% vs 45.6%, p < 0.0002, respectively). The level of TnT, 4 and 24 h after
CPB, was significantly higher in the control group compared to PUFAs group,
with statistically significant differences (11.4 vs 6.6, p < 0.009 and 12.7
vs 5.9, p < 0.008, respectively). The level of CK-MB, 4 h after CPB, was
significantly higher in the control group compared to PUFAs group (61.9 vs
37.7, p < 0.008), but its level, 24 h after CPB, was not statistically
different between the two groups (58.9 vs 40.6, p < 0.051). Conclusion.
Treatment with omega-3 PUFAs administered preoperatively promoted early
metabolic recovery of the heart after elective CABG and improved myocardial
protection. This study showed that omega-3 emulsion should not be considered
only as a nutritional supplement but also as a clinically safe and potent
cardioprotective adjunct during CPB.