Transcatheter Aortic Valve Implantation in Patients with Extra Small Aortic Annuli

Background: Transcatheter aortic valve implantation (TAVI) for treatment of severe aortic valve stenosis in patients with small aortic annuli (≤23 mm) represent a technical challenge due to risk of postoperative adverse hemodynamics in terms of elevated transvalvular pressure gradients and prosthesis-patient mismatch. Limited data exist regarding TAVI in patients with extra small aortic annuli with a diameter ≤20.5 mm. The aim of this study was to analyze outcomes of this particular subset of patients.

Methods: Between 03/2011 and 11/2021, 93 patients (93.4% female; mean age 82.7 ± 5.8 years; STS-Score and EuroSCORE II of 6.7 ± 4.9% and 6.9 ± 8.3%) with a perimeter derived aortic annulus diameter ≤20.5 mm were identified from our database including a total of 5.756 patients. Annular dimensions were assessed using pre-procedural multi-slice computed tomography (MSCT). Acute procedural and early clinical outcomes were adjudicated in accordance with standardized VARC-3 definitions.

Results: From a total of 5756 patients, 93(1.6%) presented with an aortic annulus ≤20.5 mm. Of those, 69.5% (65/93) were treated using self-expanding and 30.5%(28/93) balloon-expandable valves. Mean annular dimension was 20.2 ± 0.5 mm. TAVI was performed via transfemoral and transapical access in 91.4%(85/93) and 8.6%(8/93). Technical success, device success and early safety were 91.3%(85/93), 86.0%(80/93) and 59.1%(55/93), respectively. Reasons for absence of device success were mortality (3/93), sequential THV implantation for malpositioning (3/93) and elevated transvalvular gradient >20 mmHg (7/93). Thirty-day mortality was 3.2%(3/93). Major access site bleeding complications and permanent pacemaker implantation were observed in 9.7%(9/93) and 15.1%(15/93), respectively. Acute kidney injury, stroke and myocardial infarction occurred in 4.3%(4/93), 4.3%(4/93) and 3.2%(3/93). Postprocedure echocardiography showed paravalvular leakage (PVL) >mild in 3.2%(3/93). Mean transvalvular gradient was 10.7 ± 6.0 mmHg.

Conclusion: The prevalence of aortic annuli ≤ 20.5 mm is low. Acute outcomes in this special patient subset at particular high risk is impaired with regards to rates of mortality, stroke and elevated transvalvular gradients as direct consequence of narrow aortic annulus anatomy. Therefore, whenever feasible and clinical acceptable, surgical aortic valve replacement with aortic root enlargement should be taken into consideration when discussing these patients in the context of a heart team.