The Effect Of Dexmedetomidine Preconditioning On Perioperative Myocardial Injury For Patients With Acute Aortic Dissection

Objective: to explore the effect of dexmedetomidine preconditioning on perioperative hemodynamics and myocardial injury for patients with acute aortic dissection(Stanford type A).Methods: 30 patients with acute aortic dissection(Stanford type A) were selected to undergo Sun's operation in Sun Yat-sen hospital from March to December, 2015. They were randomly divided into 2 groups(n=15): group dexmedetomidine(group D) and control group(group C). Group D received dexmedetomidine 1?g/kg over 10 min after anesthesia induction, followed by dexmedetomidine 0.5 ?g/kg/h until the aorta cross-clamping. Group C received the same volume of normal saline at the same speed. The level of heart rate(HR) and mean arterial pressure(MAP) were recorded down at 7 time points(before receiving the load dosage t0, after 10 min of received the load dosage t1, the moment of skin incision t2 and sternotomy t3, before CPB t4, after termination of CPB t5, completing the surgry t6). The blood samples were obtained to test the concentrations of H-FABP, c Tn I and CK-MB by ELISA at 9 time points(preanesthesia, postanesthesia, after received the load dosage, aortic clamping, 15min?3h?6h?12h?24h after aortic declamping).Results: 1. There was no significant difference between two groups in gender, age, weight, hypertension history, cardiac functional grading, EF values, smoking, drinking, the time of aorta blocking, CPB and operation(P?0.05).2. HR, MAP: There was no significant difference between two groups in HR and MAP at t0, t1, t4~t6(P?0.05). Compared to group C, the level of HR and MAP in group D was significantly lower at t2, t3(P?0.05).3. H-FABP: The level of H-FABP after aortic declamping 15 min was significantly higher than that of preanesthesia(P?0.05), reached the peak level after aortic declamping 3h(P?0.05), returned to the preoperation level within 24h(P?0.05). Compared to group C, it was significantly lower in group D at 15min?3h?6h?12h after aortic declamping(P?0.05).c Tn I, CK-MB: The level of c Tn I and CK-MB after aortic declamping 3h were significantly higher than that of preanesthesia(P?0.05), reached the peak level after aortic declamping 12h(P?0.05), did not return to the preoperation level after aortic declamping 24h(P?0.05). Compared to group C, the level of c Tn I was significantly lower in group D at 6h?12h?24h after aortic declamping(P?0.05), the level of CK-MB was significantly lower in group D at 3h?6h?12h?24h after aortic declamping(P?0.05).Conclusion:1. Dexmedetomidine preconditioning can stabilize perioperative hemodynamics and reduce myocardial injury for patients with acute aortic dissection(Stanford type A).2. Compared with traditional biochemical marker c Tn I and CK-MB, H-FABP can be used as one of the biochemical marker for its earlier diagnosis in perioperative myocardial injury.