What is the recommended approach for bifurcation stenting of the left main coronary artery?

Bifurcation Stenting of the Left Main Coronary Artery

For left main coronary artery bifurcation lesions, a provisional side-branch stenting approach should be the initial strategy when the side branch is not large and has only mild to moderate focal disease at the ostium, while elective double stenting is reasonable for complex bifurcation morphology involving a large side branch with high risk of occlusion. 1

Assessment and Classification

• Evaluate bifurcation morphology using the Medina classification
• Assess side branch characteristics:
  • Size (diameter ≥2.5mm indicates significant branch)
  • Length of lesion
  • Severity of ostial disease
  • Angulation of the bifurcation

Recommended Approach Based on Anatomy

Provisional Side-Branch Stenting (Preferred Initial Strategy)

• Indicated for:
  • Low-risk bifurcations
  • Side branches with minimal/moderate ostial disease (≤50% stenosis)
  • Focal lesions (5-6mm length)
  • Small side branches

The provisional approach involves stenting the main vessel first and only treating the side branch if results are suboptimal. This strategy has shown similar clinical outcomes to elective double stenting in low-risk bifurcations, with lower incidence of periprocedural biomarker elevation 2.

Elective Double Stenting

• Reasonable for:
  • Complex bifurcation morphology
  • Large side branches (≥2.5mm)
  • High risk of side-branch occlusion
  • Low likelihood of successful side-branch reaccess 1

For distal left main bifurcation lesions, evidence suggests that results are less favorable when treated with a 2-stent approach compared to a single-stent approach. The target lesion revascularization (TLR) rate is relatively low (<5%) with single-stent approaches, even for distal left main lesions. However, patients treated with 2-stent techniques showed TLR rates as high as 25%, with restenosis confined mainly to the left circumflex ostium 1.

Technical Considerations

For Provisional Stenting:

1. Prepare both branches with balloon angioplasty
2. Stent the main vessel across the side branch
3. Perform proximal optimization technique (POT)
4. Assess side branch result
5. If side branch result is suboptimal:
   • Rewire the side branch through stent struts
   • Dilate the side branch
   • Consider final kissing balloon inflation
   • Consider additional stenting of side branch if necessary

For Elective Double Stenting:

Several techniques are available:

• Crush stenting
• Culotte stenting
• T-stenting
• Mini-crush technique

The mini-crush technique has been used successfully for distal left main bifurcation stenting 1. However, there is little consensus on the optimal dual stent approach 1.

Important Considerations

1. Intravascular Ultrasound (IVUS) Guidance:

   • IVUS is reasonable for assessment of angiographically indeterminate left main CAD 1
   • IVUS evaluation before stenting is warranted for left main interventions 1
   • IVUS helps optimize stent placement and expansion

2. Drug-Eluting Stents (DES):

   • DES yield better outcomes than bare-metal stents for bifurcation lesions 2
   • Sirolimus-eluting stents have shown better outcomes than paclitaxel-eluting stents 1

3. Final Kissing Balloon Inflation:

   • Clinical evidence supports the use of final kissing balloon inflation after elective double stenting 1

Recent Evidence

The EBC MAIN study (2021) showed that among patients with true bifurcation left main stem stenosis requiring intervention, fewer major adverse cardiac events occurred with a stepwise layered provisional approach than with planned dual stenting, although the difference was not statistically significant 3.

Additionally, in the Coronary Bifurcation Stenting registry III, left main bifurcation was associated with a higher risk of target lesion failure than non-left main bifurcation. In the left main bifurcation group, compared with the 1-stent strategy, the 2-stent strategy showed a significantly higher risk of target lesion failure, mainly driven by the higher rate of target lesion revascularization 4.

Potential Complications

• Side-branch occlusion (occurs in 8-80% of unselected patients) 1
• Restenosis (higher rates at side branch ostium)
• Stent thrombosis (increased risk in bifurcation lesions)

The risk of side-branch occlusion is related to complex bifurcation morphology, including severe and/or long side-branch ostial stenosis, large plaque burden in the side-branch ostium, and/or unfavorable side-branch angulation 1.