Related Experiment Video
Updated: May 13, 2026
Minimally Invasive Transverse Aortic Constriction in Mice
Published on: March 14, 2017
UNICORN for Valve-in-Valve Transcatheter Aortic Valve Replacement: UNICORN Hong Kong Registry
Chun-Ka Wong1, Kwong-Yue Eric Chan2, Daniel Tai-Leung Chan3
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.
Background:
Undermining Iatrogenic Coronary Obstruction With Radiofrequency Needle (UNICORN) was developed to mitigate coronary obstruction risk during valve-in-valve transcatheter aortic valve replacement (ViV-TAVR) with balloon-expandable valves (BEVs). A modified UNICORN with recrossing technique was subsequently described for self-expanding valves (SEVs).
Objectives:
This study aimed to assess early outcomes of the UNICORN technique.
Methods:
The UNICORN Hong Kong Registry was a single-center, retrospective observational study at Queen Mary Hospital, Hong Kong, including consecutive patients undergoing ViV-TAVR between July 2024 and August 2025. Patients were treated with either UNICORN using BEV or UNICORN with recrossing using SEV. The primary endpoint was procedural success, defined as successful leaflet traversal, intended leaflet laceration, and transcatheter heart valve implantation without procedural mortality, coronary obstruction, or emergency surgery. Secondary outcomes included 30-day safety events per Valve Academic Research Consortium-3.
Results:
Seventeen patients (41.2% male; 78.3 ± 6.61 years) underwent ViV-TAVR: 8 with BEV and 9 with SEV using the recrossing technique. All SEV patients had prior surgical valves, whereas in the BEV group 50.0% had surgical valves and 50.0% had transcatheter valves. Coronary ostium at risk was left in 58.8%, right in 29.4%, and bilateral in 11.8%. Median coronary height was 7.80 [7.00-8.50] mm and mean virtual transcatheter heart valve to coronary distance was 4.56 ± 1.48 mm. One patient required bileaflet modification with concomitant UNICORN and Bioprosthetic or Native Aortic Scallop Intentional Laceration to Prevent Iatrogenic Coronary Artery Obstruction. Procedural success was achieved in all patients with no coronary obstruction. At 30 days, 1 patient (5.88%) required pacemaker implantation.
Conclusions:
The UNICORN technique was feasible for preventing coronary obstruction during ViV-TAVR and warrants further evaluation in larger trials.
More Related Videos
06:59Improved Registration of 3D CT Angiography with X-ray Fluoroscopy for Image Fusion During Transcatheter Aortic Valve Implantation
Published on: June 3, 2018
09:57Four-Dimensional Computed Tomography-Guided Valve Sizing for Transcatheter Pulmonary Valve Replacement
Published on: January 20, 2022
Related Concept Videos
01:16Chambers of the Heart
Deoxygenated blood from the body is received in the right...
01:16Heart Valves
The AV valves prevent the backflow of blood from the ventricles to the atria during ventricular contraction. These valves function with the assistance of the chordae tendineae and papillary muscles. When the ventricles are relaxed, the chordae tendineae are slack, allowing blood to flow from the atria into the...