Cardioprotective effect of dexmedetomidine in patients undergoing off-pump coronary artery bypass grafting

Abstract

Objective To evaluate the cardioprotective effect of dexmedetomidine in patients undergoing off-pump coronary artery bypass grafting. Methods Forty-six ASA Ⅱ or Ⅲ patients aged 37-64 yr weighing 54-81 kg undergoing off-pump coronary artery bypass grafting were randomized into 2 groups ( n = 23 each): control group (group C) and dexmedetomidine group (group D) . Dexmedetomidine was infused at 0.5 μg·kg-1·h-1 starting after induction of anesthesia until the end of operation in group D. Radial artery was cannulated and Swan-Ganz catheter placed via right internal jugular vein. HR, MAP, mean pulmonary arterial pressure, pulmonary capilary wedge pressure, central venous pressure, and cardiac output were recorded and stroke volume index, left and right ventricular stroke work index, systemic vascular resistance and pulmonary vascular resistance were calculated at the beginning of operation (T1 ), immediately (T2 ) and at 30 min after reestablishment of coronary blood flow (T3 ) and the end of operation (T4 ) . Venous blood samples were taken before induction of anesthesia (T0 , baseline) , at T4 and 4 h (T5 ) and 24 h (T6 ) after operation for determination of plasma concentration of cardiac troponin I by ELISA. Results Stroke volume index and left ventricular stroke work index were significantly higher at T4 while systemic vascular resistance was lower at T34 in group D than in group C. Plasma cardiac troponin Ⅰ concentration was significantly lower at T6 in group D than in group C. Conclusion Dexmedetomidine infusion at 0.5 μg ·kg-1·h-1 during operation can protect myocardium in patients undergoing off-pump coronary artery bypass grafting. Key words: Dexmedetomidine;  Coronary artery bypass, off-pump;  Myocardium