Transcatheter aortic valve implantation in patients with an extremely small native aortic annulus: The OCEAN-TAVI registry

Background Transcatheter aortic valve implantation (TAVI) has been reported to be advantageous over surgical aortic valve replacement owing to the low incidence of prosthesis-patient mismatch (PPM) and large effective orifice area (EOA). However, data on TAVI for extremely small annuli are limited. The present study aimed to compare post-procedural hemodynamics and morphology between 20-mm and 23-mm Sapien XT (SXT) transcatheter heart valves (THVs) with extremely small annuli (< 314 mm²). Methods All patients with severe aortic stenosis treated with TAVI at eight Japanese centers between October 2013 and January 2016 were prospectively included in the Optimized CathEter vAlvular iNtervention (OCEAN-TAVI) registry. In the overall cohort of 20-mm (19 patients) and 23-mm SXTs (492 patients) with extremely small annuli, the patient groups were matched one-to-one using propensity scores, and post-procedural echocardiography and multidetector computed tomography data were compared for 18 matched patients from each group (matched cohort). Results In the matched cohort, the mean gradient was higher (15.4 ± 4.1 vs. 12.2 ± 4.8 mm Hg, p = 0.04), EOA was lower (1.22 ± 0.25 vs. 1.44 ± 0.37 cm², p = 0.02) and THV area was lower (245.6 ± 19.1 vs. 298.5 ± 33.3 mm², p < 0.01) in the 20-mm group than in the 23-mm group. However, all patients in both groups were asymptomatic. Although moderate PPM was more prevalent in the 20-mm group than in the 23-mm group (31.6% vs. 7.9%, p < 0.01), the incidence of severe PPM was low and similar between the groups (0% vs. 0.4%, p = 1.00) in the overall cohort. Conclusion A 20-mm SXT in patients who require a small bioprosthesis leads to favorable short-term outcomes.