Executive Summary

Coronary bifurcation lesions represent 15-20% of all percutaneous coronary interventions (PCI) and remain one of the most technically challenging procedures in interventional cardiology. These procedures have significantly higher complication rates, lower procedural success rates, and worse long-term outcomes compared to non-bifurcation lesions—even with modern drug-eluting stents.

VerAvanti's Scanning Fiber Endoscope (SFE) technology has the potential to address multiple critical unmet needs in bifurcation PCI, particularly in areas where current imaging modalities (IVUS and OCT) have significant limitations.

This document outlines specific clinical challenges and how SFE could provide differentiated solutions.

Critical Issues in Bifurcation PCI & SFE Solutions

1. Carina Visualization and Assessment

The Problem

• Overlapping Anatomy: Coronary angiography cannot accurately visualize the carina area due to overlapping of the main vessel (MV) and side branch (SB).

• Limited Assessment: This limitation severely restricts accurate assessment of atherosclerotic involvement at the bifurcation core.

• Carina Shift: One of the primary mechanisms of side branch compromise (alongside plaque shift) is carina/plaque shift toward the side branch during main vessel stenting.

• Current Imaging Gaps:

  • 2D OCT has difficulty visualizing the complex 3D anatomy of the carina region.

  • Even 3D OCT reconstructions don't provide real-time assessment and slow down the procedure.

  • IVUS lacks the 3D visualization needed to clearly delineate carina morphology.

    
    

SFE Advantage

• Forward-Looking View: SFE's unique forward-looking capability could provide real-time, direct visualization of the carina from the main vessel.

• Dynamic Assessment: Ability to observe carina position and morphology before, during, and after stent deployment.

• Clinical Impact: Better prediction and prevention of side branch compromise, improved procedural planning and streamlined execution (provisional vs. two-stent strategy).

2. Side Branch Ostium Visualization

The Problem

• Assessment Challenges: The side branch ostium is difficult to visualize accurately with standard imaging.

• 2D OCT Limitations: Cross-sectional OCT images from main vessel pullbacks cannot adequately assess SB ostial area and geometry.

• Critical Clinical Consequences:

  • Side branch occlusion occurs in 7-16% of cases.

  • SB ostium is the most common site of in-stent restenosis in bifurcation lesions.

  • Gaps in stent coverage at the SB ostium are a major contributor to restenosis.

  • Angiographic appearance of SB ostium is unreliable (only 27% of cases with ≥75% angiographic narrowing have functionally significant stenosis).

SFE Advantage

• Direct Ostial Visualization: SFE could provide direct, en-face visualization of the SB ostium from within the main vessel.

• Real-Time Ostial Area Measurement: Ability to quantify the SB ostial opening immediately after main vessel stenting.

• Jailing Strut Assessment: Direct visualization of stent struts overlying the SB ostium to determine if intervention is needed.

• Hemodynamic Correlation: Visual assessment of SB ostium geometry without need for pressure wire studies in every case.

• Clinical Impact: Reduced need for SB intervention in cases with adequate ostial opening, earlier detection of significant compromise requiring treatment.

3. Guidewire Recrossing Optimization

The Problem

• Critical Technical Step: Guidewire recrossing position before final kissing balloon inflation is crucial for reducing incomplete stent apposition (ISA).

• Detection Challenges:

  • Angiography is completely unreliable for detecting recrossing position.

  • IVUS is also unreliable for this assessment.

  • OCT can detect position but requires pullback and offline analysis.

  • Studies show 33% of first recrossing attempts go through proximal cells.

• Consequences of Incorrect Recrossing:

  • Increased incomplete stent apposition (40.6% vs 26% with optimal recrossing).

  • Reduced SB ostial coverage (60% vs 81% strut-free lumen area).

  • Higher risk of stent thrombosis and restenosis.

  • Deflected stent struts protruding into vessel lumen.

SFE Advantage

• Real-Time Strut Visualization: SFE's forward-looking view could directly visualize stent struts and cells as the guidewire approaches.

• Immediate Confirmation: Operators could confirm distal cell recrossing in real-time without needing to perform OCT pullback.

• Procedural Efficiency: Eliminate trial-and-error approach to finding optimal recrossing position.

• Link Connection Detection: Identify when link connections are positioned at the carina (which restricts strut mobility even with distal recrossing).

• Abluminal Wiring Prevention: Direct visualization would prevent guidewire from crossing outside the stent (abluminal position), which causes serious deformation.

• Clinical Impact: Significantly reduced malapposition, improved procedural success, faster procedure times, reduced need for corrective maneuvers.

4. Plaque Distribution and Bifurcation Core Assessment

The Problem

• Pre-Procedural Planning: Critical to assess plaque distribution before selecting provisional vs. two-stent strategy.

• Eccentric Plaque: When plaque is distributed eccentrically opposite to the carina, SB occlusion risk is low.

• Bifurcation Core Stenosis: Higher stenosis within bifurcation core (within 5mm of carina) significantly increases SB occlusion risk.

• Plaque Vulnerability: Proximal main vessel shows more plaque accumulation and vulnerability than distal segments.

• Current Limitations:

  • Angiography cannot determine plaque distribution in 3D space relative to carina.

  • IVUS provides information but requires detailed analysis.

  • OCT has contrast requirements and penetration limitations.

    
    

SFE Advantage

• Direct Plaque Visualization: Forward-looking view of plaque distribution relative to the carina and SB ostium.

• Color-Coded Assessment: Potential to provide enhanced tissue characterization using SFE's spectral capabilities.

• Real-Time Strategy Adjustment: Ability to modify approach based on actual plaque distribution observed during procedure.

• Minimal Contrast: Could reduce total contrast volume compared to OCT imaging sequences.

• Clinical Impact: Better pre-procedural planning, more accurate risk stratification, informed decision-making for stenting strategy.

5. Proximal Optimization Technique (POT) Guidance

The Problem

• Critical Step: POT is essential after provisional stenting to optimize proximal main vessel segment.

• Positioning Challenges:

  • POT balloon distal marker must be placed just proximal to carina.

  • If POT extends beyond carina, causes over-expansion of distal MV and SB closure through carina shift.

  • Inaccurate balloon placement causes incomplete stent adhesion to lateral SB wall.

  • Even correctly positioned POT can cause elliptical deformation of SB ostium.

• Clinical Importance: POT associated with reduced target lesion failure (4% vs 6%) and stent thrombosis (0.4% vs 1.3%).

• Current Challenges: Relies primarily on angiographic landmarks which may not accurately show carina position.

  
  

SFE Advantage

• SB Ostium Monitoring: Simultaneous assessment of SB ostium during POT to detect any compromise.

• Optimization Verification: Confirm adequate proximal stent apposition without carina shift.

• Clinical Impact: More precise POT execution, reduced SB compromise, improved stent apposition.

6. Calcium Assessment and Lesion Preparation

The Problem

• Calcium Critical Factor: Heavily calcified lesions are major predictor of procedural complications.

• Bifurcation-Specific Challenges:

  • Need adequate lesion preparation in all three limbs of bifurcation.

  • Calcified plaques require different preparation strategy.

• Current Assessment:

  • OCT can measure calcium thickness accurately but requires contrast.

  • IVUS shows calcium but with lower resolution.

  • Neither provides forward-looking assessment during device advancement.

    
    

SFE Advantage

• Pre-Intervention Calcium Mapping: Forward-looking assessment of calcium distribution at bifurcation.

• Preparation Verification: Confirm adequate calcium modification before stent deployment.

• Clinical Impact: Better lesion preparation reduced acute complications, improved stent expansion.

  
  

Comparative Analysis: SFE vs. Current Imaging Modalities

IVUS Limitations in Bifurcations

• Lower resolution (100-150 μm) vs SFE potential.

• Side-looking only; cannot see ahead.

• Difficult to assess carina and SB ostium geometry.

• Requires pullback, no real-time forward assessment.

• Limited ability to guide wire recrossing.

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OCT Limitations in Bifurcations

• High contrast requirements (problematic in bifurcations).

• Side-looking only; limited carina visualization.

• 2D cross-sections difficult to interpret in complex 3D bifurcation anatomy.

• 3D reconstruction typically offline, not real-time.

• Penetration limitations for calcium assessment.

• Cannot assess SB ostium adequately from MV pullback, smaller vessel size limitations.

  
  

SFE Unique Advantages

• Forward-Looking: Only technology providing real-time view of anatomy ahead.

• Real-Time 3D Perspective: Natural spatial understanding of bifurcation geometry.

• Direct Carina Visualization: Can "see around the corner" into side branch.

• No Need for Contrast: Important for bifurcation procedures which often require multiple imaging runs.

• Wire Guidance: Direct visualization for optimal guidewire positioning.

• Integration: Potential to combine with IVUS/OCT for comprehensive assessment.