Comparison of Transcatheter Aortic Valve Replacement between Self-Expanding versus Balloon-Expandable Valves in Patients with Small Aortic Annulus

Background and Objectives: Transcatheter aortic valve replacement (TAVR) has been reported as a good alternative for surgical aortic valve replacement in patients with small aortic annulus. Head-to-head comparisons of different transcatheter aortic valves in these patients are insufficient. We compared the outcomes after TAVR between two different types of recent transcatheter aortic valves (self-expanding vs. balloon-expandable) in patients with small aortic annulus. Methods: A total of 70 patients with severe aortic stenosis and small annulus (mean diameter ≤23 mm or minimal diameter ≤21 mm on computed tomography) underwent TAVR with either a self-expanding valve with supra-annular location (n=45) or a balloon-expandable valve with intra-annular location (n=25). The echocardiographic hemodynamic parameters after TAVR and 1-year follow-up were compared. Results: Between the self-expanding and balloon-expandable valve-treated patients, the clinical outcomes including permanent pacemaker implantation (11.1% vs. 8.0%), acute kidney injury stage 2 or 3 (4.4% vs. 4.0%), and major vascular complication (4.4% vs. 0.0%) were similar without all-cause mortality, stroke, and life-threatening bleeding during 30-day follow-up. Compared with the balloon-expandable valve-treated patients, the self-expanding valve-treated patients presented larger effective orifice area (EOA) (1.46±0.28 vs. 1.75±0.42 cm², p=0.002) and indexed EOA (0.95±0.21 vs. 1.18±0.28 cm²/m², p=0.001), whereas mean aortic valve gradient (11.7±2.9 vs. 8.9±5.2 mmHg, P=0.005) and incidence of ≥moderate prosthesis-patient mismatch (36.0% vs. 8.9%, p=0.009) were lower. These hemodynamic differences were maintained at 1-year follow-up. Conclusions: TAVR with self-expanding valves was associated with superior hemodynamic outcomes compared with balloon-expandable valves in patients with small aortic annulus.