Risk stratification in the patient with ST elevation MI

Definition

 * Chest pain or classic symptoms for more than 30 minutes.
 * ST-segment elevation of at least 1 mV in 2 contiguous leads, or new left bundle branch block.
 * Increase of cardiac enzyme levels.

Risk stratification in patient presenting with STEMI

 * The Thrombolysis in Myocardial Infarction (TIMI) risk score for STEMI:
 * The TIMI risk score for STEMI was created from simple arithmetic sum of independent predictors of mortality weighted according to the adjusted odds ratios from logistic regression analysis.
 * The patient pool (n=14114) came from the Intravenous nPA for Treatment of Infarcting Myocardium Early II trial (TIME II).
 * The TIMI risk score was subsequently validated in an unselected heterogeneous community population through the National Registry of Myocardial Infarction (NRMI) 3 & 4.
 * The Global Registry of Acute Coronary Events (GRACE) risk score for ACS:
 * The GRACE risk score was created from a multivariable logistic regression model using ACS patients enrolled in the GRACE registry (N=11389).
 * The GRACE risk score was validated using subsequent cohort of patients enrolled in GRACE (n=3972) and the Global Use of Strategies to Open Occluded Coronary Arteries IIb (GUSTO-IIb) trial (n=12142).

Primary percutaneous coronary intervention versus thrombolysis therapy

 * Several randomized multi-center clinical trials have demonstrated superiority of primary PCI in comparison to thrombolysis. A review of 23 clinical trials found PCI was better than thrombolysis in reducing short term mortality (7% vs 9%; P=0.0002), death excluding the SHOCK trial data (5% vs 7%; p=0.0003), non-fatal reinfarction (3% vs 7%; p<0.0001), stroke (1% vs 2%; p=0.0004) and the combined end point of death, non-fatal reinfarction and stroke (8% vs 14%; p<0.0001) (Primary angioplasty versus intravenous thrombolytic therapy for acute myocardial infarction: a quantitative review of 23 randomised trials. Keeley EC et al; Lancet 2003 Jan 04;361(9351):13-20).
 * ACC/AHA guideline on management of STEMI gave the following recommendation regarding to PCI:
 * Class I indication:
 * Expected door to balloon time goal of 90 minutes or less.
 * Duration of symptom is less than 3 hours and the expected door to balloon time minus the expected door to needle time for thrombolysis is less than 1 hour. Otherwise, thrombolysis is generally preferred.
 * Duration of symptom is greater than 3 hours.
 * Patient is in cardiogenic shock and has severe congestive heart failure and/or Killip class III.
 * Class IIa indication:
 * Patient 75 years or above who developes cardiogenic shock within 36 hours of MI onset who can be revascularized within 18 hours of sock.
 * Duration of symptom within 12-24 hours with severe CHF and/or Killip class III, hemodynamic or electric instability, or persistent ischemia.