Why is Coronary Artery Bypass Grafting (CABG) preferred over cardiac catheterization with Percutaneous Coronary Intervention (PCI) for severe coronary artery disease?

CABG vs PCI for Severe Coronary Artery Disease

CABG is preferred over PCI for severe coronary artery disease because it provides superior long-term survival, lower rates of myocardial infarction, and reduced need for repeat revascularization, particularly in patients with left main disease, multivessel disease with diabetes, or complex coronary anatomy (SYNTAX score >22). 1

Disease-Specific Recommendations

Left Main Disease

For left main coronary stenosis at low surgical risk, CABG is the overall preferred revascularization mode over PCI due to lower risk of spontaneous myocardial infarction and repeat revascularization. 1

However, the choice depends critically on anatomical complexity:

• Low complexity (SYNTAX score ≤22): PCI is an acceptable alternative to CABG when equivalent completeness of revascularization can be achieved, offering lower invasiveness with non-inferior survival. 1

• Intermediate complexity (SYNTAX score 23-32): PCI should be considered as an alternative, maintaining non-inferior survival with reduced invasiveness. 1

• High complexity (SYNTAX score ≥33): PCI is not recommended; CABG is strongly preferred. 1, 2

Multivessel Disease with Diabetes

CABG is definitively recommended over both medical therapy alone and PCI in diabetic patients with multivessel disease to improve symptoms and outcomes, regardless of anatomical complexity. 1 This represents one of the strongest indications for CABG, with 5-year major adverse cardiac and cerebrovascular events of 18.7% for CABG versus 26.6% for PCI. 3

• For diabetic patients with three-vessel disease and low SYNTAX score (0-22), PCI may be considered but remains inferior to CABG. 1
• For diabetic patients with three-vessel disease and intermediate or high SYNTAX score (>22), PCI is not recommended. 1

Three-Vessel Disease Without Diabetes

CABG is recommended over medical therapy alone to improve symptoms, survival, and other outcomes in patients with preserved left ventricular ejection fraction (LVEF). 1

The choice between CABG and PCI depends on anatomical complexity:

• Low-to-intermediate complexity: When PCI can provide similar completeness of revascularization to CABG, PCI is recommended given its lower invasiveness and generally non-inferior survival. 1

• Complex anatomy: CABG is preferred due to superior long-term outcomes. 2, 4

Proximal LAD Involvement

Both CABG and PCI are recommended over medical therapy alone for single- or double-vessel disease involving the proximal LAD with insufficient response to guideline-directed medical therapy. 1, 5

The decision algorithm is straightforward:

• Complex lesions less amenable to PCI: CABG is specifically recommended to improve symptoms and reduce revascularization rates. 1, 5, 6

• Simple anatomy: Either CABG or PCI is acceptable. 5, 6

Single- or Double-Vessel Disease Not Involving Proximal LAD

PCI is the recommended approach for symptomatic patients with insufficient response to guideline-directed medical therapy. 1 CABG may only be considered when lesions are not amenable to PCI. 1

Key Outcome Differences

Mortality and Morbidity

CABG demonstrates superior outcomes in specific populations:

• Survival benefit: CABG provides improved long-term survival in multivessel disease, particularly with complex anatomy. 2, 4, 3
• Myocardial infarction: Lower rates with CABG compared to PCI in left main and multivessel disease. 1
• Repeat revascularization: Substantially lower with CABG (5.9% vs 13.5% for PCI at 12 months in three-vessel or left main disease). 4, 3

Trade-offs

• Stroke risk: Significantly higher with CABG (2.2% vs 0.6% for PCI at 12 months). 4
• Invasiveness: PCI offers lower procedural invasiveness, making it preferable in high surgical risk patients. 1

Risk Stratification Tools

SYNTAX score calculation is mandatory to assess anatomical complexity in multivessel obstructive coronary artery disease. 1, 2 This score directly determines the appropriateness of PCI versus CABG:

• SYNTAX ≤22: PCI is a reasonable alternative to CABG in most scenarios
• SYNTAX 23-32: CABG generally preferred, PCI considered in selected cases
• SYNTAX ≥33: CABG strongly preferred

STS score calculation is recommended to estimate in-hospital morbidity and 30-day mortality after CABG. 1

Special Populations

Heart Failure with Reduced LVEF

In patients with LVEF ≤35% and multivessel disease, CABG is recommended over medical therapy alone to improve long-term survival. 1 This represents a critical prognostic indication for surgical revascularization. 6

High Surgical Risk Patients

In patients at very high surgical risk with multivessel disease, PCI should be considered over medical therapy alone to reduce symptoms and adverse outcomes. 1

Common Pitfalls

• Underestimating complexity: Failing to calculate SYNTAX score leads to inappropriate PCI selection in complex anatomy where CABG would provide superior outcomes. 1, 2

• Ignoring diabetes status: Diabetic patients with multivessel disease consistently benefit more from CABG regardless of anatomical complexity, yet PCI is sometimes inappropriately chosen. 1, 3

• Overlooking completeness of revascularization: PCI is only equivalent to CABG when complete revascularization can be achieved; incomplete revascularization negates PCI's benefits. 1, 5