# UNICORN for Valve-in-Valve Transcatheter Aortic Valve Replacement: UNICORN Hong Kong Registry

## TL;DR

The UNICORN technique was tested to prevent coronary obstruction during a heart valve replacement procedure, showing success in 17 patients with no major complications.

## Contribution

The study introduces and evaluates a modified UNICORN technique for self-expanding valves in valve-in-valve TAVR.

## Key findings

- Procedural success was achieved in all 17 patients with no coronary obstruction.
- One patient required a pacemaker implantation within 30 days.
- The technique was used with both balloon-expandable and self-expanding valves.

## Abstract

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).

This study aimed to assess early outcomes of the UNICORN technique.

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.

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.

The UNICORN technique was feasible for preventing coronary obstruction during ViV-TAVR and warrants further evaluation in larger trials.