CABG for Three-Vessel Disease: When to Operate
CABG is a Class I recommendation (should be performed) for all patients with three-vessel coronary artery disease, with the survival benefit being even greater when left ventricular ejection fraction is less than 50%. 1
Core Indications for CABG in 3VD
CABG should be performed in three-vessel disease regardless of symptom severity, as the survival benefit exists independent of anginal symptoms. 1 This is a critical point—do not defer surgery in asymptomatic or mildly symptomatic patients with anatomically significant 3VD. 1
The strength of the CABG recommendation increases based on these specific anatomic and clinical features:
Anatomic Complexity (SYNTAX Score)
- For complex 3VD (SYNTAX score >22), CABG is mandatory over PCI, as PCI in this population results in significantly higher rates of death, myocardial infarction, and repeat revascularization at 5 years. 2, 3
- PCI should not be performed when SYNTAX score ≥33—this is a Class III (contraindicated) recommendation. 1
- For low anatomic complexity (SYNTAX score ≤22), PCI becomes an acceptable alternative only if complete revascularization can be achieved, though repeat revascularization rates remain significantly higher (25.4% vs 12.6% at 5 years). 3, 4
Left Ventricular Function
- CABG should be performed in patients with poor LV function (EF <50%) who have 3VD, as the survival benefit is amplified in this population. 2, 5
- For severe LV dysfunction (EF <35%), CABG remains reasonable even without documented viability, though the presence of viable myocardium strengthens the indication. 5
- Use the left internal mammary artery to the LAD in every case—this is mandatory and provides >90% patency at 10 years. 1, 6
Diabetes Mellitus
- CABG is mandatory over both medical therapy and PCI in diabetic patients with 3VD, with substantially amplified mortality benefit. 1
- At longest follow-up (up to 14 years), diabetic patients with 3VD who underwent CABG had significantly lower mortality (49.6% vs 57.6%), myocardial infarction (15.6% vs 28.1%), and repeat revascularization (7.7% vs 26.9%) compared to PCI. 7
- The FREEDOM trial demonstrated 5-year MACCE of 18.7% for CABG versus 26.6% for PCI in diabetics with multivessel disease. 8
Ischemia Burden
- For 3VD with extensive ischemia (>20% perfusion defect, high-risk stress test findings, or abnormal intracoronary hemodynamics), CABG improves survival. 2
- Even with 2-vessel disease, if there is severe/extensive myocardial ischemia or target vessels supply a large area of viable myocardium, CABG is reasonable for survival benefit. 2
Clinical Scenarios Requiring Urgent/Emergency CABG
- Life-threatening ventricular arrhythmias in the presence of 3VD: Class I indication for emergency CABG. 2
- Cardiogenic shock within 18 hours of onset: CABG should be performed unless further support is futile. 2
- Failed PCI with ongoing ischemia or hemodynamic compromise: Immediate CABG is indicated. 2
Critical Timing Considerations
Avoid CABG within 3-7 days of acute MI unless there is ongoing ischemia with hemodynamic compromise, as surgical mortality is elevated during this window. 2, 1, 5 Beyond 7 days post-infarction, standard revascularization criteria apply. 2
Common Pitfalls to Avoid
- Do not withhold CABG based on age alone—the benefit-to-risk ratio remains favorable in elderly patients when surgical risk is acceptable. 1
- Do not defer CABG waiting for symptoms to worsen—survival benefit exists regardless of symptom severity in 3VD. 1
- Do not perform emergency CABG in hemodynamically stable patients with persistent angina but only a small area of myocardium at risk—this is Class III (should not be done). 2
- Do not choose PCI over CABG simply because the patient prefers a less invasive approach when anatomic complexity (SYNTAX >22) or diabetes is present—the mortality difference is substantial. 3, 7
When PCI Becomes Acceptable
PCI is an acceptable alternative to CABG only when all of the following criteria are met: