Impact of underfilling and overfilling in balloon-expandable transcatheter aortic valve implantation assessed by multidetector computed tomography: Insights from the Optimized CathEter vAlvular iNtervention (OCEAN-TAVI) registry

Background Underfilling or overfilling of balloon-expandable transcatheter heart valves (THVs) during transcatheter aortic valve implantation (TAVI) is commonly used to improve conformity to small or calcified annuli in order to avoid serious complications. However, little is known about this technique. This study assessed the effects of underfilling and overfilling of THVs. Methods and results Data from 213 consecutive TAVI patients treated with balloon-expandable THVs in 4 Japanese centers between October 2013 and December 2014 were prospectively analyzed; 23-mm and 26-mm THVs were implanted in 96 cases (56 underfilling, 22 nominal filling, and 18 overfilling) and 38 cases (23 underfilling and 15 nominal filling), respectively. Pre/postprocedural multidetector computed tomography (MDCT) and echocardiographic data were compared. MDCT revealed that the minimum area of the underfilled 23-mm THVs was significantly decreased compared to that of nominal filled and overfilled THVs (308.3 SD 26.1 vs. 333.9 SD 14.7 vs. 347.8 SD 21.3 mm², respectively, p < 0.0001); analogous results were demonstrated for underfilled 26-mm THVs compared to nominal filled THVs (386.2 SD 34.6 vs. 423.6 SD 17.3 mm², respectively, p = 0.0004). The postprocedural transvalvular gradient of underfilled 23-mm THVs was significantly higher than that of nominal filled and overfilled THVs, while there were no differences for 26-mm THVs. Conclusions Underfilling or overfilling of THVs is safe and feasible, conforming to the original annulus and covering a continuous range of annular sizes with limited THV size options. However, care should be taken when underfilling 23-mm THVs due to the potential for increased transvalvular gradient.