UNICORN Technique to Prevent Coronary Obstruction During TAVI: Initial Results From a Multicenter Study

Coronary obstruction is an uncommon but potentially catastrophic complication of transcatheter aortic valve implantation (TAVI), particularly in valve-in-valve procedures, TAV-in-TAV interventions, or in patients with high-risk anatomies, such as low coronary height or sinus of Valsalva sequestration. The BASILICA technique has been shown to reduce this risk through intentional longitudinal leaflet laceration before valve implantation; however, it has technical limitations in certain anatomical scenarios. 

UNICORN (Undermining Coronary Obstruction with Radiofrequency Needle) is a leaflet modification technique that, after crossing the leaflet with an electrosurgical guidewire, performs progressive balloon dilations within the leaflet tissue, allowing valve implantation through the created opening or producing complete leaflet tearing before valve deployment. This retrospective multicenter study evaluated the initial outcomes of this strategy.

The primary efficacy endpoint was procedural success, defined as successful implantation using the UNICORN technique without coronary obstruction, death, emergency surgery, or periprocedural reintervention. The primary safety endpoint was a 30-day composite of death, stroke, coronary obstruction requiring reintervention, stage 3–4 acute kidney injury, life-threatening bleeding, major vascular complications, and valve reintervention. Intraprocedural hypotension was also evaluated.

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A total of 53 consecutive patients treated between March 2024 and May 2025 at nine centers in the United States and the United Kingdom were included. The median age was 78 years, 64% were women, and the median STS-PROM score was 7.0% (IQR 4.5–11.8); 45% were at high surgical risk and 36% at intermediate risk. Eight patients (15%) underwent treatment on native valves, 30 (57%) underwent valve-in-valve procedures in surgical bioprostheses, and 15 (28%) underwent TAV-in-TAV procedures. The left coronary artery was considered at risk of obstruction in 51% of cases, the right coronary artery in 17%, and both coronary arteries in 32%. 

The predominant anatomical mechanism was sinus of Valsalva sequestration (60%), followed by narrow sinuses (40%). Transfemoral access was used in 91% of procedures, cerebral embolic protection devices in 77%, and SAPIEN 3 and Evolut valves were implanted in 83% and 17% of patients, respectively. In 40 patients (76%), the prosthesis expanded within the channel created inside the leaflet without causing complete leaflet tearing (intraleaflet deployment), whereas in 13 patients (24%), complete leaflet tearing was achieved before valve implantation.

Technical success was high. Leaflet crossing, valve implantation, and intraprocedural survival were achieved in 100% of cases, while overall procedural success reached 96% (51/53). Two patients (4%) developed left main coronary artery obstruction, both successfully treated with coronary stent implantation. Overall 30-day safety was 87%.

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No deaths, stage 3–4 acute kidney injury, or valve reinterventions were reported. Three strokes (6%) occurred, including one disabling stroke (2%), along with two life-threatening bleeding events (4%) and two major vascular complications (4%). Intraprocedural hypotension occurred in 12 patients (23%) and resolved in all cases after valve implantation. Secondary events included one periprocedural myocardial infarction (2%), with no cases of pericardial effusion, cardiac tamponade, or endocarditis at 30 days.

Conclusion: UNICORN showed high efficacy but requires careful patient selection

In conclusion, the UNICORN technique proved to be an effective strategy for preventing coronary obstruction during TAVI. However, intraprocedural hypotension was frequent, and concerns remain regarding a potential increase in thromboembolic events, particularly stroke. The authors conclude that this technique should be reserved for patients in whom lower-risk alternatives are unlikely to succeed and emphasize the need for prospective studies to better define its clinical indications.

Original Title: UNICORN During Transcatheter Aortic Valve Replacement in Native and Bioprosthetic Aortic Valves: A Multicenter Study

Reference: Elsa Hebbo, MD; John T. D’Angelo, MD; et al. JACC: Cardiovascular Interventions. 2026;19:1595-1603.