Should a 70% Left Anterior Descending (LAD) artery lesion be revascularized even if the patient is asymptomatic?

Revascularization of Asymptomatic 70% LAD Lesion

Revascularization should be performed for an asymptomatic 70% LAD lesion, particularly if it involves the proximal LAD, as it provides survival benefit according to current guidelines. 1, 2

Rationale for Revascularization

The decision to revascularize an asymptomatic 70% LAD stenosis is supported by strong evidence:

• The ACC/AHA guidelines provide a Class IIa recommendation (Level of Evidence: B) for CABG with a LIMA graft to improve survival in patients with significant (>70% diameter) stenosis in the proximal LAD artery and evidence of extensive ischemia 2
• Proximal LAD disease carries higher risk than lesions in other locations, with studies showing:
  • Higher rates of myocardial infarction during long-term follow-up 3
  • Worse survival curves in patients with proximal versus distal LAD disease 4
  • Increased 1-3 year mortality with significant proximal LAD narrowing 5

Assessment Before Revascularization

Before proceeding with revascularization:

1. Confirm functional significance of the stenosis with FFR/iFR if not already done 1
2. Assess left ventricular function, as the indication for revascularization is stronger if LVEF is reduced (<50%) 1, 2
3. Evaluate for presence of ischemia through non-invasive testing, which strengthens the indication for revascularization 2

Revascularization Strategy

The choice between PCI and CABG should consider:

• For isolated proximal LAD disease:

  • Either PCI or CABG is appropriate 1
  • CABG with LIMA graft offers lower repeat revascularization rates (5% vs 24% for stenting) 6
  • PCI with drug-eluting stents is a reasonable alternative with good long-term outcomes 3

• If multivessel disease is present:

  • CABG is generally preferred, especially with diabetes or complex anatomy 1
  • CABG provides survival benefit in patients with significant stenoses in 3 major coronary arteries or in the proximal LAD plus another major coronary artery 2

Important Considerations

• Asymptomatic status does not guarantee freedom from risk, as silent ischemia can lead to sudden cardiac events 1
• The presence of a 70% LAD stenosis meets the anatomical threshold for significant disease according to guidelines 2
• Proximal LAD disease combined with right coronary artery obstruction carries mortality risk comparable to left main disease 4
• The DEFINE-FLAIR trial showed that deferral of LAD revascularization based on negative physiologic assessment (FFR or iFR) is safe, emphasizing the importance of functional assessment 7

Potential Pitfalls

• Avoid deferring revascularization solely based on absence of symptoms, as this may lead to missed opportunities to improve survival
• Don't proceed with revascularization without confirming functional significance if there's uncertainty about the hemodynamic impact of the stenosis
• Consider patient-specific factors such as age, comorbidities, and bleeding risk when selecting the revascularization strategy
• Remember that the benefit of revascularization is most pronounced in patients with reduced left ventricular function

In conclusion, despite being asymptomatic, a 70% LAD lesion warrants revascularization based on current guidelines and evidence demonstrating survival benefit, particularly if it involves the proximal LAD segment.