What is the best view for ostial Left Main Coronary Artery (LMCA) stenting?

Optimal Angiographic Views for Ostial LMCA Stenting

For ostial left main coronary artery (LMCA) stenting, use RAO 23°, CAU 45° as the primary fluoroscopic view to achieve en face visualization of the ostium, with IVUS guidance strongly recommended for optimal stent positioning and deployment verification.

Primary Fluoroscopic Projection

• The optimal en face angle for the left coronary ostium is RAO 23°, CAU 45°, based on MSCT analysis of coronary ostial anatomy 1
• This projection provides direct perpendicular visualization of the ostial plane, minimizing foreshortening and overlap 1
• Patient-specific viewing angles determined from pre-procedural MSCT data can substantially facilitate ostial interventions 1

Critical Technical Considerations

Why Conventional Angiography Alone Is Inadequate

• Exact evaluation of LMCA disease by conventional angiography is difficult due to large vessel size, short normal reference segments, overlapping of major vessels, aortic cusp opacification, contrast streaming, and varied angulations 2
• These anatomic and hemodynamic factors make ostial lesion assessment particularly challenging and prone to error 2

Mandatory IVUS Guidance

• IVUS assessment is advocated in most cases for stent optimization in LMCA interventions 2
• IVUS evaluation before stenting is warranted to accurately assess lesion characteristics that angiography cannot visualize 2
• IVUS allows verification of minimum stent area, malapposition, underexpansion, and edge dissection after deployment 3
• A minimum stent area <4.5-5.0 mm² by OCT is an independent predictor of major adverse cardiac events 3

Stent Positioning Strategy

Avoiding Geographic Miss

• Verify final stent position in multiple views before post-dilation to avoid geographic miss (incomplete lesion coverage) 3
• For ostial lesions, slight stent protrusion (1-2mm) into the aorta may be necessary to ensure complete ostial coverage 3
• Coaxial alignment is critical for optimal stent delivery and deployment 3

Supplementary Views

• Use multiple projections including caudal, non-angled, and cranial RAO views for comprehensive evaluation 4
• The caudal RAO view increases diagnostic accuracy for proximal LAD and circumflex segments 4
• Intracoronary imaging guidance is associated with lower risk of target vessel failure in complex lesions 3

Clinical Outcomes and Pitfalls

Superior Results for Ostial Lesions

• Ostial and midshaft LMCA lesions have significantly better outcomes than bifurcation lesions, with restenosis rates of 1.7% versus 10.9% and TVR rates of 3% versus 13% 2
• Procedural success rates of 99% are achievable with mean late lumen loss of only 0.01 mm in non-bifurcation LMCA lesions 2

Common Pitfalls to Avoid

• Inadequate ostial coverage can lead to early restenosis requiring repeat intervention 5
• Relying solely on angiographic guidance without IVUS increases risk of suboptimal stent expansion 2
• Because restenosis or stent thrombosis can be catastrophic at LMCA locations, all measures for achieving optimal final result must be employed 2

Post-Deployment Verification

• Use IVUS to confirm adequate stent expansion, apposition, and complete lesion coverage 2
• Verify absence of edge dissection or geographic miss in multiple angiographic projections 3
• Ensure minimum stent area meets criteria (≥4.5-5.0 mm²) to reduce risk of adverse events 3