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BenchTop Validation of UNICORN Leaflet Modification Technique in Redo-Transcatheter Aortic Valve Replacement
Simon Cheung-Chi Lam1, Ho-On Alston Conrad Chiu1, Kwong-Yue Eric Chan2
1Cardiology Division, Department of Medicine, School of Clinical Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China; Cardiology Division, Department of Medicine, Queen Mary Hospital, Hong Kong SAR, China.
The UNICORN technique for valve-in-valve TAVR shows promise for preventing coronary obstruction. Bench testing defined optimal balloon sizing and confirmed coronary clearance, though one valve platform resisted intraleaflet deployment.
Area of Science:
- Cardiovascular interventions
- Biomedical engineering
- Structural heart disease
Background:
- Coronary obstruction is a significant risk during valve-in-valve transcatheter aortic valve replacement (TAVR).
- The UNICORN technique, involving intraleaflet valve deployment, aims to mitigate this risk.
- Limited bench testing data exists for the UNICORN technique.
Purpose of the Study:
- Evaluate leaflet behavior after intraleaflet balloon dilatation across various transcatheter heart valve (THV) platforms.
- Simulate crossing a second THV through de novo fenestrations.
- Assess leaflet behavior during and after deployment.
Main Methods:
- In vitro bench testing using SAPIEN 3, Evolut, Navitor, and ACURATE neo2 THV platforms.
- Sequential balloon dilatation of leaflets (8-14 mm) to determine maximum tolerable size without laceration.
- Assessed minimum fenestration size for second THV crossing, deployment feasibility, and postdeployment geometry.
Main Results:
- Most THV leaflets tolerated balloon dilatation up to 12-14 mm without laceration.
- A 12-14 mm fenestration size was generally sufficient for second THV crossing.
- Intraleaflet deployment was successful for SAPIEN 3, Evolut, and ACURATE neo2, confirming coronary clearance.
- The Navitor platform resisted successful intraleaflet deployment, showing frame distortion and tilting.
Conclusions:
- Optimal balloon sizing for the UNICORN technique was defined for common THV platforms.
- Coronary clearance was confirmed in successful deployments.
- One THV platform demonstrated resistance to intraleaflet deployment, requiring further investigation before widespread clinical adoption.
