Leaflet Modification Technique With UNICORN in Failed Aortic Bioprosthesis: Procedural Step-by-Step, Best Practice, and Troubleshooting.

The UNICORN (undermining iatrogenic coronary obstruction with radiofrequency needle) technique was developed in 2022 to reduce the risk for coronary obstruction during valve-in-valve transcatheter aortic valve replacement. The procedure involves traversing the target leaflet with an electrified wire, followed by serial dilation with coronary and peripheral balloons. A balloon-expandable valve is then delivered into the de novo fenestration for intraleaflet deployment. As the balloon-expandable valve expands, the target leaflet is opened and displaced away from the at-risk coronary ostium, resulting in a minimal neoskirt on the target side. Since its introduction, the technique has been adopted at numerous centers worldwide, with various modifications and adaptations. In this paper, a step-by-step description of the UNICORN procedure is provided, and troubleshooting strategies for potential challenges are discussed.