Special strategy for STEMI
STEMI needs early reperfusion and hence special strategies to minimise the first medical contact (FMC) to reperfusion time. In a center capable of primary PCI, the aim is to achieve a door to balloon time of less than 90 minutes. The earlier the infarct related artery is opened, the better, as more myocardium is salvaged – ‘time means muscle’, in terms of salvaged myocardium at jeopardy. If the patient presents to a center without PCI facility, if transfer and PCI is feasible within 120 minutes, that has to be given top priority. In such situations, door in door out (DIDO) time should be less than 30 minutes. In hospital processes should be optimized for early transfer after an abbreviated initial assessment and ECG. If transfer and PCI is not feasible due to logistic reasons, aim is to thrombolyse within 30 minutes at the initial hospital itself. After thrombolysis, transfer for elective PCI in 3-24 hours should be considered. Early transfer is indicated for failed thrombolysis as indicated by ongoing ischemic pain and no resolution of ST segment.
Primary PCI in STEMI
Primary PCI is indicated in those STEMI patients with ischemic symptoms of less than 12 hour duration, more so if there is a contraindication for thrombolysis. The latter is irrespective of time delay from first medical contact. Cardiogenic shock or acute severe heart failure are indications for primary PCI irrespective of time delay from the onset of myocardial infarction. All these are Class I indications. If there is evidence of ongoing ischemia between 12-24 hours after onset of symptom, there is still a Class IIa indication for primary PCI.
Thrombolysis at Non PCI center
While taking up for thrombolysis at non PCI capable center, several aspects have to be considered. Time from onset of symptoms is very important as a fresh clot can be lysed easier, typically with time from symptom onset less than 3 hours. If if it is a delayed case, PCI has an edge over. Risk of complications related to STEMI and the preparedness of the center for dealing with them is needed. Bleeding risk with thrombolysis and potential readiness for transfusion if needed is another aspect. Presence of shock or severe heart failure almost mandates transfer for PCI. Transfer time to PCI center is equally important so as to achieve early reperfusion in case transfer is being opted.