Treatment of Non-ST-Elevation Myocardial Infarction (NSTEMI)

Immediate Medical Therapy

• The American College of Cardiology recommends that all NSTEMI patients should receive immediate dual antiplatelet therapy (aspirin plus clopidogrel or another P2Y12 inhibitor) combined with anticoagulation, followed by risk stratification to determine whether an early invasive strategy or an initial conservative strategy is most appropriate 1, 2
• Aspirin should be initiated immediately in all patients unless contraindicated, as recommended by the American Heart Association 3, 1, 2
• Clopidogrel should be added to aspirin as dual antiplatelet therapy, as recommended by the American College of Cardiology 1, 2
• Enoxaparin (LMWH) is preferable to unfractionated heparin unless renal failure is present or CABG is planned within 24 hours, according to the American College of Cardiology 2
• Anticoagulation should be added to antiplatelet therapy in all patients, as recommended by the American Heart Association 2
• Beta-blockers should be administered unless contraindicated, as recommended by the American College of Cardiology 3, 4
• Nitrates should be used for symptom relief and ongoing ischemia, as recommended by the American Heart Association 3, 4

Risk Stratification for Invasive Strategy Selection

• The American College of Cardiology identifies patients who benefit most from routine early invasive management, including those with elevated troponin, ST-segment deviation, TIMI risk score ≥3, recurrent ischemia, hemodynamic instability, and sustained ventricular arrhythmias 1, 2
• Elevated troponin (troponin T >0.01 ng/mL or troponin I >0.1 ng/mL) is a high-risk feature that favors early invasive strategy, as recommended by the American Heart Association 2

Treatment Strategy Selection

• For patients with high-risk features, an early invasive strategy with coronary angiography performed within 12-48 hours followed by revascularization if appropriate provides superior outcomes compared to conservative management, according to the American College of Cardiology 1, 2
• The TACTICS-TIMI 18 trial demonstrated that in high-risk patients treated with aspirin, heparin, and GP IIb/IIIa inhibitor (tirofiban), early invasive strategy reduced death/MI/rehospitalization at 6 months from 19.4% to 15.9% (p=0.025) 2
• The FRISC-II trial showed 1-year mortality of 2.2% with invasive strategy versus 3.9% with conservative strategy (p=0.016) 4, 2

Revascularization Method Selection

• Drug-eluting stents are preferred over balloon angioplasty alone when PCI is performed, as recommended by the American College of Cardiology 2
• Coronary Artery Bypass Grafting (CABG) is reserved for patients with anatomy unsuitable for PCI or with left main/multivessel disease where CABG provides superior outcomes, according to the American Heart Association 1

Secondary Prevention

• Dual antiplatelet therapy continuation (aspirin plus P2Y12 inhibitor) is recommended for all patients, as recommended by the American College of Cardiology 1, 5
• High-intensity statin therapy is recommended for aggressive lipid lowering, according to the American Heart Association 1, 5
• Beta-blockers should be continued unless contraindicated, as recommended by the American College of Cardiology 3, 4

Critical Clinical Pitfalls to Avoid

• Delaying invasive strategy in truly high-risk patients can lead to worse outcomes, as shown in the ISAR-COOL trial, which demonstrated that delayed invasive strategy (86 hours) had worse outcomes than very early strategy (2.4 hours) 4, 6
• Using troponin elevation alone as the sole criterion for invasive strategy selection can lead to inappropriate treatment, as recommended by the American Heart Association 3, 5
• Combining clopidogrel with omeprazole or esomeprazole can significantly reduce antiplatelet efficacy, according to the American College of Cardiology 2
• Assuming all patients benefit equally from early invasive strategy can lead to overtreatment or undertreatment, as the benefit is primarily in medium- to high-risk patients, not low-risk patients 2, 7

Management of Non-ST-Elevation Myocardial Infarction (NSTEMI)

Immediate Medical Therapy and Risk Stratification

• The American College of Cardiology recommends proceeding immediately to catheterization laboratory for patients with refractory angina despite maximal medical therapy, as indicated by the Journal of the American College of Cardiology in 2013 and Circulation in 2011 8, 9
• The American College of Cardiology suggests an early invasive strategy within 12-24 hours for high-risk patients, as recommended by the Journal of the American College of Cardiology in 2013 8
• The use of an intravenous GP IIb/IIIa inhibitor (eptifibatide or tirofiban) is generally recommended in UA/NSTEMI patients undergoing PCI, according to Circulation in 2011 9, 10
• PCI is indicated for patients with coronary lesions amenable to PCI and high-risk features, as indicated by Circulation in 2011 9, 10
• CABG is preferred for left main disease >50% stenosis, multivessel disease with diabetes or LV dysfunction, and anatomy unsuitable for PCI, as recommended by Circulation in 2011 9, 10
• The American College of Cardiology advises against administering fibrinolytic therapy in NSTEMI patients, as demonstrated by multiple trials, including TIMI 11B, and recommended by Circulation in 2011 and the Journal of the American College of Cardiology in 2013 8, 11

Management of Non-ST-Elevation Myocardial Infarction (NSTEMI)

Immediate Medical Therapy

• The American College of Cardiology recommends administering aspirin 162-325 mg loading dose, then 75-100 mg daily indefinitely, and a P2Y12 inhibitor, such as ticagrelor 90 mg twice daily or prasugrel 60 mg loading dose then 10 mg daily, for higher-risk patients not requiring urgent CABG, with clopidogrel 75 mg daily as an alternative if ticagrelor or prasugrel are contraindicated, and continuing P2Y12 inhibitor for at least 12 months regardless of stent type 12

Risk Stratification and Timing of Invasive Strategy

• High-risk patients should undergo angiography within 12-24 hours if they have elevated troponin levels, dynamic ST-segment or T-wave changes, TIMI risk score ≥3 or GRACE score >140, LVEF <40%, diabetes mellitus, prior PCI or CABG, or sustained ventricular arrhythmias, according to the American College of Cardiology 12, 13
• The American College of Cardiology recommends proceeding directly to catheterization laboratory for patients with refractory angina, hemodynamic instability, cardiogenic shock, life-threatening ventricular arrhythmias, mechanical complications of MI, or recurrent angina with ST-segment depression ≥0.05 mV or new bundle branch block 12, 13

Glycoprotein IIb/IIIa Inhibitors

• The American College of Cardiology recommends using eptifibatide or tirofiban in high-risk UA/NSTEMI patients undergoing PCI, and avoiding upstream routine use, according to the American College of Cardiology 14

Critical Pitfalls to Avoid

• The American College of Cardiology advises against delaying invasive strategy in high-risk patients, as the ISAR-COOL trial showed worse outcomes with delayed approach, and against proceeding with early invasive strategy in patients with extensive comorbidities, acute chest pain with low likelihood of ACS, or patients who will not consent to revascularization 12, 13, 14