ACS is the most common cardiac emergency . Management of STEMI is relatively straight forward. The only decision that to be taken is the modality of reperfusion. (Primary PCI or thrombolysis.) There is no need to risk stratify STEMI on arrival. All STEMI patients are considered high risk on admission. Whereas NSTEMI consists of a heterogeneous population. They need to be triaged into low intermediate or high risk categorizes on arrival.There is two management approaches for unstable angina .All high risk UA should enter early invasive strategy . And low risk and intermediate risk group will get early conservative management.
The principle of management of UA differ from STEMI in a fundamental way , as there is no issue of myocardial salvage in UA .The primary aim is to provide relief from pain and prevent an MI. So in the strict sense there is no time window in unstable angina /NSTEMI.
But it is generally considered 48 hours is the time limit for an early invasive approach.If the patient has crossed this time there is apparently no great difference in outcome for conservative and invasive approach.
Dr.S.Venkatesan MD 