preconditioning of no debate has a valuable effect upon myocardial protection . pre-cardiopulmonary bypass pre-conditioning , suspected to have a role upon postoperative inotropic support

Preconditioning (PC) of the heart occurs when brief exposure to a stimulus protects the heart from subsequent ischemia. PC stimulus may be ( ischemic ;pharmacologic or Physical) Pharmacological pc may be induced by variable agents e.g. (Sevoflurane ;isoflorane, opioids etc ) Ischemic pc includes local ;remote and the idea is temporary interruption of blood supply to the organ so that liberation of protective mediators occurs The liberated mediators have favorable effects not only upon the myocardium But ;it extend to protect other organs against inflammatory activation ;ischemia reperfusion injury Inotropic score IS is already an evident predictor of postoperative cardiac mobidity and mortality

Inclusion Criteria:

• adult patient
• valve replacement surgery
• ASA grade 2 or 3

Exclusion Criteria:

• emergency surgery
• - poor general conditions
• impaired hepatic or renal function
• peripheral vascular disease
• patient refusal