L-Arginine Cardioplegia Reduces Oxidative Stress and Preserves Diastolic Function in Patients with Low Ejection Fraction Undergoing Coronary Artery Surgery
What this study found
L-arginine cardioplegia improved markers of oxidative stress and early diastolic function but did not reduce postoperative troponin I. Coronary sinus malondialdehyde was lower at 5 minutes (0.28±0.12 vs 0.48±0.32 nmol/ml; P=0.0004) and 15 minutes (0.31±0.14 vs 0.38±0.15; P=0.0004), while superoxide dismutase activity was higher at both times (229±87 vs 191.3±68 units/ml; P=0.005; 229±54 vs 198±15; P=0.005). Lactic acid flux was also lower at 1, 5, and 15 minutes (P=0.0003 for each), and early diastolic mitral annular velocity improved more after bypass (P=0.018). In contrast, cTnI rose over…
- Study & population
- Single-center randomized comparison in adults undergoing elective primary CABG with left ventricular ejection fraction <35% at The Royal Melbourne Hospital, Melbourne, Australia.
- Intervention
- L-arginine hydrochloride was added to blood cardioplegia during elective coronary artery bypass grafting.
- Key limitation
- Small single-center study in high-risk CABG patients with low ejection fraction, limiting generalizability.
View source
Open PDFOriginal abstract
L-arginine cardioplegia decreases biochemical markers of myocardial damage and oxidative stress in patients with normal left ventricular function. We investigated the effects of L-arginine supplemented cardioplegic arrest in patients with reduced ejection fraction. Fifty-three adult patients with left ventricular ejection fraction <35% undergoing elective coronary artery bypass surgery were randomised to receive blood cardioplegia with or without L-arginine. Following cardiopulmonary bypass, measured endpoints were cardiac troponin-I concentration at 12 and 24 hours, coronary sinus concentrations of malondialdehyde and superoxide dismutase activity at five and 15 minutes, lactic acid flux at one, five and 15 minutes and left ventricular systolic and diastolic function after protamine administration. There were no differences in cardiac troponin-I between groups. Malondialdehyde was lower in L-arginine group, 0.28±0.12 vs 0.48±0.32 (5 minutes) and 0.31±0.14 vs 0.38±0.15 nmol.ml−1 (15 minutes) (P=0.0004). Superoxide dismutase activity was higher in L-arginine group, 229±87 vs 191.3±68 (5 minutes), 229±54 vs 198±15 nmol.minute−1.ml (15 minutes) (P=0.005). Lactic acid flux was lower in the L-arginine group, 0.15±0.23 vs 0.48±0.32 (1 minute), 0.08±0.19 vs 0.38±0.31 (5 minutes) and −0.15±0.13 vs 0.26±0.30 mmol.l−1 (15 minutes), (P=0.0003). There was no difference in left ventricular systolic function. The mitral annular tissue Doppler inflow (eʹ) velocity during early diastole improved in the L-arginine group following cardiopulmonary bypass (control 4.2±1.9 cm.s−1 to 3.6±1.2 cm.s−1 vs L-arginine 3.8±1.2 cm.s−1 to 4.6±1.4 cm.s−1) (P=0.018). In patients with reduced ejection fraction, L-arginine supplemented cardioplegic arrest did not affect postoperative cardiac troponin-I levels, but attenuated cardiac cellular peroxidation and improved early left ventricular diastolic function.