Effects of levocamitine cardioplegic solution on cardio-myocyte apoptosis in patients undergoing heart valve replacement with cardiopulmonary bypas / 中华麻醉学杂志

ABSTRACT

Objective To investigate the effects of levocarnitine used as an ingredient of cardioplegic solution on cardiomyocyte apoptosis in patients undergoing heart valve replacement under cardiopulmonary bypass (CPB) .Methods Twenty-four NYHA grade Ⅱ or Ⅲ patients of both sexes (16 males, 8 females) aged 27-67 yrs undergoing heart valve replacement under CPB were randomly allocated into 2 groups (n = 12) levocarnitine group and control group. In levocarnitine group levocarnitine 6 g was added to 1 000 ml of 4℃ St Thomas Ⅱ cardioplegic solution, while in control group equal volume of normal saline was added instead of levocarnitine. Cardioplegic solution 15 ml?kg-1 was injected to perfuse the heart every 30 min during aortic cross-clamping. The KC1 concentration of the cardioplegic solution was reduced by half for the last injection. During CPB the naso pharyngeal temperature was maintained at 25-27℃. Cardiac index (CI) and left ventricular ejection fraction (LVEF) were measured 1 day before and 7 days after operation using heart color ultrasonography. A small piece of myocardial tissue was obtained from right atrium for assessment of apoptosis using terminal deoxynueleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) . The expression of Bax and Bcl-2 in cardiomyocytes was determined by immuno-histochemistry, and Bcl-2/Bax ratio was calculated. Results The rate of restoration of spontaneous heart beat after aortic unclamping was significantly higher in levocarnitine group than in control group (86.6% vs 47.3%) (P