Study On The Protective Effects Of Electroacupuncture Preconditioning On Cardiac Ischemic Injury And Early Pocd In Patients Undergoing Cardiac Surgery

Open heart surgery is an effective way to treat various kinds of structural heart disease including congenital heart disease, rheumatic heart disease, coronary heart disease et al. As we all know, open heart surgery under cardiopulmonary bypass (CPB) may induce ischemic reperfusion injury (IRI) and postoperative cognitive dysfunction (POCD). Though hypothermia, medicine and various ischemic preconditioning methods have been applied to protect myocardium after open heart surgery, different levels of ischemia, hypoxia still exist, which slowed the recovery and reduced the quality of lives of patients. On the mean time, studies showed the incidence rate of POCD after open heart surgery is much higher than that of general surgery. Thus, how to prevent and treat IRI and POCD is continuously a hot topic of study.Previous study from our lab showed that electroacupuncture (EA) preconditioning can simulate the cardioprotective effects of ischemic preconditioning, which reduced the volume of cerebral infarction and improve the nervous functional grade in elder mouse. Our present study was designed to address the protective effects of repeated EA preconditioning on myocardial injury in patients undergoing heart valve replacement surgery. We also discussed the possibility of electroacupuncture preconditioning in preventing the occurance of POCD after open heart surgery.Part 1 Cardioprotective Effects of Electro-acupuncture Preconditioning in Patients Undergoing Heart Valve Replacement Objective: This study was designed to address the protective effects of electro-acupuncture (EA) pretreatment on myocardial injury in patients undergoing heart valve replacement surgery. Methods: Sixty patients diagnosed with acquired heart valve diseases were randomly allocated to the EA pretreatment group or control group (n=30 each). According to the theory of Traditional Chinese Medicine, bilateral Neiguan (PC 6), Lieque (LU 7) and Yunmen (LU 2) were chosen and the acupuncture points were stimulated electrically with the intensity of 2-4(2.34-6.24mA), and frequency of 5/30 Hz for 30 min using the Hwato SDZ-II Nerve and Muscle Stimulator (Suzhou Hua Tuo Medical Instruments Co., Ltd., Suzhou, China). The pretreatment was individualized based on patients sex, age, weight and felt and given 1 time per day for 5 consecutive days before the heart valve replacement surgery.Anesthesia, cardiopulmonary bypass and surgery were performed by the same surgery group. Hemodynamic data, mechanical ventilation time, inotropic drug use in ICU, serum cTnI concentrations, morbidities and mortalities were compared between the two groups. This trial is registered with ClinicalTrials.gov, number NCT00732459. Results: Analysis of serum cTnI showed a significant difference between EA group and Control group, level of serum cTnI in EA group were significant lower than those in the control group. At the time points of 6h, 12h and 24h after reperfusion, levels of serum cTnI were significantly decreased in the EA group. ICU length of stay in the EA group was shorter than that of the control group (P=0.049). The inotrope scoring showed the EA group were lower than those in the control group at 12 h, 24 h and 48 h after the ICU arrival (P<0.05). Conclusions: This prospective, single-centered, randomized controlled study showed that EA pretreatment inhibited the elevation of troponin-I, reduced the inotrope use, and shortened the ICU stay time in the postoperative period after heart valve replacement surgery, suggesting a potential myocardial protective effect of EA pretreatment.Part 2 Influence of EA Preconditioning on POCD in Patients Undergoing Cardiac SurgeryAIM To observe the effect of electroacupuncture preconditioning on POCD in patients undergoing heart valve replacement surgery and coronary artery bypass grafting (CABG) with cardiopulmonary bypass under general anesthesia.METHODS One hundred and six patients (male 49, female 57) were randomly allocated to electroacupuncture preconditioning group (EA) and control group. Electroacupuncture preconditioning group were treated at bilateral Neiguan (PC 6), Lieque (LU 7) and Yunmen (LU 2) with electrical stimulation (5-30 Hz, 2.34-6.24 mA, 30min) for 5 consecutive days before the heart valve replacement surgery and CABG. Before operation and 7d and 14d after operation, all the patients were required to take a battery of 5 neuropsychological tests, including mini-mental state examination, digit span test, digit symbol test, trial making test and short story memory test. RESULTS A total of 75 patients completed the tests (38 in EA group and 37 in control group). No significant difference was found in age, gender, height, weight and education level between the 2 groups (P>0.05). The incidence of postoperative cognitive dysfunction in EA group and control group was 26.3% and 24.3% 7d after operation, and 10.5% and 13.5% 14d after operation respectively. Statistical analysis showed no significant difference between the 2 groups (P >0 . 05). CONCLUSION Electroacupuncture preconditioning did not show protective effect on the incidence of cognitive dysfunction in patients undergoing heart valve replacement and CABG with cardiopulmonary bypass under general anesthesia.