Comparison of the Effect of Two Anaesthesia Methods in Preventing Perioperative Myocardial Infarcation in Patients With Cardiac Risk Undergoing Total Knee Arthroplasty

Inclusion Criteria: * presence and/or risk for coronary artery disease (CAD) as well as planned lower extremity surgery was considered. Presence of CAD was ascertained by history of myocardial infarction and diagnosis of typical angina or atypical angina with a positive stress test \& ECG finding. Risk for CAD included age (\> 65 years old), hypertension, smoking habit, blood cholesterol (\>240 mg/dL), and diabetes. Exclusion Criteria: * 1\) severe impairment of left ventricular function (ejection fraction \< 40 %). 2) renal failure requiring hemodialysis. 3) known allergies to the drugs used in the present study. 4) contraindications to regional blocks (localized infection, and use of an antiplatelet drug within 3 days before the surgery). 5) unusual blood coagulation tests.