[Myocardioprotective effects of preconditioning in patients undergoing open heart operation].
OBJECTIVE
To investigate the myocardial protective effects of ischemic preconditioning (IP) on adult patients who undergoing prolonged open heart operation for complex heart diseases.


METHODS
30 patients were evenly divided into two groups at random. IP was elicited twice for 2 minutes ischemia from occlusion of vena cava and aorta followed by 3 minutes of reperfusion under cardiopulmonary bypass. Dynamic changes of ATP and purine metabolites in myocardium were measured. Electrocardiogram, leakage of myocardial enzymes, activities of SOD and LPO in serum and myocardial mechanics were investigated.


RESULTS
IP reduced ATP repletion and maintained a higher ATP content in ischemic myocardium (P < 0.05 vs control group at 30, 60, and 90 minutes of ischemia). Reduced inosine content was found in IP group (P > 0.05). The inosine/adenosine ratio at 30, 60 and 90 minutes of ischemia was 4.2 vs 14.1, 17.6 vs 28.2, 29.2 vs 71.3 for the IP and control groups, respectively, P < 0.05). There were also significant differences between the two groups in changes of ST-segment shifting, myocardial contractile and early postoperative recovery.


CONCLUSIONS
IP can reduce ischemia-reperfusion injury on prolonged ischemic myocardium in humans even when combined with cold cardioplegia. Decreased inosine production and inosine/adenosine ratio in ischemic myocardium may be an important mechanism of IP, by which the production of oxygen free radicals are decreased during early reperfusion.
Lu
E
E
Department of Cardiothoracic Surgery, Xiangya Hospital, Hunan Medical University, Changsha.
Chen
S
S
Hu
T
T
D000255:Adenosine Triphosphate / Q000378:metabolism; D000328:Adult; D002315:Cardiopulmonary Bypass; D005260:Female; D006801:Humans; D019157:Ischemic Preconditioning, Myocardial; D008297:Male; D015428:Myocardial Reperfusion Injury / Q000517:prevention & control*; D011684:Purine Nucleosides / Q000378:metabolism
D011684:Purine Nucleosides; D000255:Adenosine Triphosphate