What are the indications for percutaneous transluminal coronary angioplasty (PTCA) in patients with non-ST elevation myocardial infarction (NSTEMI)?

Indications for PTCA in NSTEMI

An early invasive PCI strategy is indicated for NSTEMI patients with high-risk features including elevated troponin, recurrent ischemia despite medical therapy, heart failure, hemodynamic instability, or serious ventricular arrhythmias. 1

Class I Indications (Strongly Recommended)

High-Risk Clinical Features

• Patients with any high-risk features should proceed to early invasive strategy with PCI if coronary anatomy is suitable and no serious comorbidities exist. 1 High-risk features include:
  • Elevated cardiac troponin levels 1
  • Recurrent angina or ischemia at rest or with low-level activity despite intensive medical therapy 1
  • New or worsening heart failure or mitral regurgitation 1
  • Hemodynamic instability 1
  • Sustained ventricular tachycardia or ventricular fibrillation 1
  • High-risk findings on noninvasive testing (LVEF <0.40, large perfusion defects, high-risk Duke treadmill score ≤−11) 1
  • Prior PCI or CABG 1

Specific Anatomic Scenarios

• 1- or 2-vessel CAD (with or without proximal LAD involvement) with large area of viable myocardium and high-risk criteria on noninvasive testing 1
• Multivessel coronary disease with suitable anatomy, normal LV function, and no diabetes mellitus 1
• Focal saphenous vein graft lesions in poor surgical candidates (Class IIa) 1

Adjunctive Therapy

• Intravenous GP IIb/IIIa inhibitors are generally recommended in NSTEMI patients undergoing PCI, particularly those with elevated troponin 1

Class IIa Indications (Reasonable to Perform)

• 1- or 2-vessel CAD with moderate area of viable myocardium and ischemia on noninvasive testing 1
• Single-vessel disease with significant proximal LAD involvement 1
• Significant left main CAD (>50% stenosis) in patients not eligible for CABG or requiring emergent intervention for hemodynamic instability 1

Class IIb Indications (May Be Considered)

• In absence of high-risk features, PCI may be considered for single-vessel or multivessel CAD with lesions having reduced likelihood of success 1
• 2- or 3-vessel disease with proximal LAD involvement in patients with treated diabetes or abnormal LV function, if anatomy suitable for catheter-based therapy 1

Class III Indications (NOT Recommended)

Absolute Contraindications

• Patients with 1- or 2-vessel CAD without significant proximal LAD involvement who have no current symptoms or symptoms unlikely due to ischemia and no ischemia on noninvasive testing 1
• Patients without high-risk features who have not had trial of medical therapy 1
• Only small area of myocardium at risk 1
• Lesion morphology conveying low likelihood of success 1
• High risk of procedure-related morbidity or mortality 1
• Insignificant disease (<50% coronary stenosis) 1
• Significant left main CAD when patient is CABG candidate 1
• Stable patients with persistently occluded infarct-related arteries after NSTEMI 1

Timing Considerations

Low- and intermediate-risk NSTEMI patients may undergo symptom-limited stress testing if clinically stable and asymptomatic for 2-5 days, with coronary angiography reserved for those with high-risk findings. 1 The 2014 ACC/AHA guidelines emphasize that coronary angiography is usually indicated when patients have recurrent symptoms despite adequate medical therapy or demonstrate high-risk features. 1

Critical Pitfalls to Avoid

Do not perform PCI in stable NSTEMI patients with occluded infarct arteries beyond 24 hours without ongoing ischemia or hemodynamic instability—the OAT trial demonstrated no benefit and potential harm. 1 The trial showed trends toward excess reinfarction during 4-year follow-up in patients who underwent routine PCI of persistently occluded arteries 3-28 days post-MI. 1

Multivessel PCI at the time of initial intervention is Class IIb (may be reasonable) rather than routine practice—culprit lesion-only PCI remains the standard approach unless the patient is in cardiogenic shock. 1

Patient Selection Algorithm

1. Assess for high-risk features (troponin elevation, recurrent ischemia, HF, arrhythmias, hemodynamic instability) 1
2. If high-risk features present → proceed to early invasive strategy within 24-48 hours 2
3. If low-intermediate risk → optimize medical therapy and perform risk stratification with noninvasive testing at 2-5 days 1
4. If high-risk findings on noninvasive testing → proceed to coronary angiography 1
5. Determine revascularization strategy based on coronary anatomy, LV function, comorbidities, and patient preferences 1