Clinic Research On Risk Factors Of Myocardial Ischemia After Noncardiovascular Surgery

Objective:Through researching postoperative myocardial ischemia andcardiovascular events in clinical patients with coronary heart disease or risk factors of coronary heart disease, to explore the incidences of myocardial ischemia and cardiovascular events after surgery and the association of postoperative myocardial ischemia and cardiovascular events, to search the predisposing cause of postoperative myocardial ischemia and the meaningful monitoring marks, to improve the postoperative monitoring and treatment and reduce the perioperative morbidity and mortality. Method: According to the "ACC/AHA Guideline for Perioperative Cardiovascular Evaluation for Noncardiac Surgery" , ninety-eight patients who have high, intermediate or more than two low risk factors were included. Patients' history materials were collected after preoperative interview. Patients were monitored with Holter system(V₁, V₄, V₅)as they were carried into operation rooms. The administering doctor decides the anesthesia method according to surgery plans and patients' conditions. Anesthesia drugs use and induction were administered at the same standard. After surgery, patients were monitored and treated aggessively in SICU to maintain the balance of myocardial oxygen supply and demand. Monitoring marks included bloodstream dynamics, bloodgas analysis, electrolyte, stress level(corticosterid, blood glucose, IL-6), cTnI(cardiac troponin I), temperature, pain score(visual analogue score). Holter monitoring lasted 48 hours during postoperative period. Patients were followed in hospital. Aggressive treatments included routine oxygen supply, avoiding anaemia, heart rates and blood pressure control, decreasing preload, postload and ventricle wall tension, maintaining the balance of acid-base, electrolyte, blood glucose and gas,prevention and treatment of arrhythmia, enough analgesia and sedation, maintaining normal temperature. According to the results of the Holter monitoring, patients were classified into postoperative ischemic group and nonischemic group. Results were compared using t or X2 statistic between two grups. Logistic regression were attempted in mutivariate analysis. Result: There were 44 patients undergoing perioperative myocardial ischemia(intraoperation 9 vs postoperation 19 vs both intraoperation and postoperation 16).There were 11 postoperative cardiovascular events(ischemia group 9 vs nonischemia group 2) in 98 patients. Postoperative hypotension were 27 (ischemia group 16 vs nonischemia group 11). Postoperative hypothermia were 15(ischemia group 10 vs nonischemia group 5). Postoperative hypomagnesemia were 2(ischemia group 1 vs nonischemia group 1). Hypoxemia were 4(ischemia group 4 vs nonischemia group 0). Hyposodemia were 17(ischemia group 6 vs nonischemia 11). Hypokalemia were 17(ischemia group 7 vs nonischemia 10). Hypocalcemia were 37(ischemia group 18 vs nonischemia 19). Tachycardia were 66(ischemia group 33 vs nonischemia group 33). Anaemia were 13(ischemia group 5 vs nonischemia group 8). Conclusion: Postoperative myocardial ischemia is the alarming mark of postoperative cardiovascular events. Postoperative tachycardia, hypotension, hypothermia and hypoxemia are the risk factors of postoperative myocardial ischemia.