When is revascularization with percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG) recommended for patients with stable ischemic heart disease?

Revascularization in Stable Ischemic Heart Disease

Revascularization with PCI or CABG in stable ischemic heart disease is primarily indicated for patients with persistent symptoms despite optimal medical therapy, high-risk coronary anatomy, or large areas of ischemia, but not for asymptomatic patients with limited disease. 1

Indications for Revascularization

For Survival Benefit

1. Class I (Strong) Indications:

   • Left main coronary artery disease >50% stenosis 1
   • Multivessel disease with left ventricular dysfunction (LVEF <35%) 1
   • Single remaining patent vessel with >50% stenosis 1

2. Class IIa (Moderate) Indications:

   • Significant proximal LAD disease >50% 1
   • Multivessel disease with moderate LV dysfunction 1
   • PCI for significant left main disease when outcomes are considered equivalent to CABG 1

3. Class IIb (Weak) Indications:

   • Multivessel disease with normal LV function, even with proximal LAD involvement 1

For Symptom Relief

1. Class I (Strong) Indications:

   • Any stenosis >50% with limiting angina or angina equivalent unresponsive to optimal medical therapy 1
   • Moderate to severe symptoms not controlled by medical therapy when procedural risks do not outweigh potential benefits 1

2. Class IIa (Moderate) Indications:

   • Dyspnea/heart failure with >10% LV ischemia/viability supplied by >50% stenotic artery 1
   • Mild to moderate symptoms unacceptable to the patient when procedural risks do not outweigh benefits 1

Decision Algorithm for Revascularization

1. First Step: Optimal Medical Therapy

   • All patients with stable ischemic heart disease should receive guideline-directed medical therapy (GDMT) 1
   • GDMT includes antiplatelet therapy, statins, beta-blockers, ACE inhibitors/ARBs as appropriate, and risk factor modification

2. Assessment for Revascularization:

   • Symptom Status: Evaluate persistence of angina despite GDMT
   • Ischemic Burden: Assess extent and severity of ischemia (>10% of LV considered significant) 1
   • Coronary Anatomy: Evaluate for high-risk features (left main, proximal LAD, multivessel disease)
   • LV Function: Assess for systolic dysfunction

3. Choice Between PCI and CABG:

   • CABG Preferred:

     • Left main or equivalent disease 1
     • Three-vessel disease, particularly with abnormal LV function 1
     • Diabetes with multivessel disease 1
     • Complex coronary anatomy (high SYNTAX score) 1

   • PCI Preferred:

     • Single-vessel disease 1
     • Multivessel disease without high-risk anatomy 1
     • Lower SYNTAX scores in left main disease 1
     • Higher surgical risk patients 1

Recent Evidence and Controversies

The ISCHEMIA trial has significantly impacted revascularization recommendations, showing that in patients with moderate-to-severe ischemia, an initial conservative strategy of optimal medical therapy was non-inferior to routine invasive strategy for the outcomes of death or myocardial infarction 2, 3. However, several important points should be noted:

• Revascularization provided better angina relief and quality of life compared to medical therapy alone 1
• The trial was not powered to detect differences in long-term mortality beyond 5 years 1
• CABG may have been underutilized in many appropriate patients in the trial 3

Common Pitfalls and Caveats

1. Overreliance on Angiographic Appearance:

   • Visual assessment of stenosis severity on angiography may under or overestimate functional significance 1
   • Consider fractional flow reserve (FFR) measurements to identify functionally significant lesions 1

2. Inappropriate Revascularization:

   • Revascularization should not be performed in asymptomatic patients with limited disease and no evidence of ischemia 4
   • Up to 45% of elective cardiac catheterizations do not detect clinically significant stenoses 4

3. Incomplete Revascularization:

   • Incomplete anatomic revascularization after PCI and CABG is strongly associated with subsequent death, MI, and recurrent angina 1

4. Neglecting Medical Therapy:

   • Revascularization is not an alternative to GDMT but should be complementary 1
   • All patients require GDMT regardless of revascularization strategy to prevent progression of atherosclerosis and coronary thrombosis

Special Considerations

1. Diabetes:

   • CABG is generally preferred over PCI in diabetic patients with multivessel disease 1, 5
   • CABG shows improved survival and reduced need for repeat revascularization in this population 5

2. Elderly Patients:

   • Consider frailty, comorbidities, and life expectancy when recommending revascularization 1
   • Patient preferences and quality of life goals should be incorporated into decision-making

3. Left Main Disease:

   • CABG has traditionally been the standard of care
   • PCI may be reasonable in selected patients with less complex anatomy (low SYNTAX score) 1

In conclusion, while all patients with stable ischemic heart disease should receive optimal medical therapy, revascularization provides additional benefits in specific high-risk anatomical patterns and in patients with persistent symptoms despite medical therapy. The decision between PCI and CABG should be based on coronary anatomy, clinical factors, and patient preferences, ideally with input from a multidisciplinary heart team.