Feasibility and challenges of the UNICORN technique in native aortic valve transcatheter aortic valve implantation

An 84-year-old female with severe native aortic stenosis was admitted for transcatheter aortic valve implantation (TAVI). Following a multidisciplinary Heart Team discussion, she was deemed unsuitable for cardiac surgery due to frailty, elevated surgical risk (Society of Thoracic Surgeons score of 6.2%), and patient preference. Computed tomography (CT) demonstrated a high risk of left coronary obstruction (Figure 1).

Several coronary protection techniques have previously been described, including chimney stenting, BASILICA (bioprosthetic aortic scallop intentional laceration to prevent iatrogenic coronary artery obstruction), UNICORN (undermining iatrogenic coronary obstruction with radiofrequency needle), and LLAMACORN (leaflet laceration with balloon-mediated annihilation to prevent coronary obstruction with radiofrequency needle). Chimney stenting involves deploying a stent that protrudes into the aorta and is associated with risks of stent deformation and thrombosis, and may compromise future coronary access.1 BASILICA, the first leaflet modification technique to be described, has demonstrated efficacy in reducing the risk of coronary occlusion, although unpredictable leaflet splay may occur, thus resulting in coronary occlusion, especially in cases of high coronary eccentricity.12 UNICORN is an alternative leaflet modification strategy, consisting of...