Computed Tomography Geometry of Extremely Undersized SAPIEN 3 Transcatheter Aortic Valves With Balloon Overfilling

Expansion of balloon-expandable valves in transcatheter aortic valve replacement (TAVR) beyond nominal volumes is feasible ex vivo. 1 Balloon over ﬁ lling in SAPIEN 3/Ultra (S3) (Edwards Lifesciences) TAVR in undersized anatomies has had favorable short-to mid-term outcomes 2 – 4 ; however, the degree of valve expansion achieved with balloon over ﬁ lling has not been systematically evaluated. Our study aimed to determine the computed tomography (CT) – derived geometry of S3 TAVR deployed with balloon over ﬁ lling in undersized anatomies and the associated impact on valve function

with 17.4% being female.On semiquantitative analysis, no patient had moderate or severe annular or LVOT calcification.Annular undersizing for each valve was 10.3% AE 2.0% for 23 mm, 7.8% AE 4.8% for 26 mm, and 12.3% AE 6.3% for 29 mm.Mean volumes added to 23 mm, 26 mm, and 29 mm S3 valves were 1.9 AE 0.3 mL, 2.2 AE 0.7 mL, and 3.2 AE 1.3 mL, respectively.All patients underwent successful transfemoral TAVR with conscious sedation.Postdilatation occurred in 2 patients (8.7%), with the same volume being used in one case and an additional 1 mL in the other.Post-TAVR CT dimensions and geometric indices of each valve size at the inflow, midframe, and outflow are shown in Figure 1.No valve achieved an expansion index of >1 at the midframe portion, ie, greater than the respective valve's nominal valve area, but 29 mm S3 had an expansion index of >1 at inflow and outflow.One patient with 26 mm S3 had hypoattenuating leaflet thickening on 30-day CT that resolved after anticoagulation.
4][5] This study showed that despite EAU and balloon overfilling, the valve expansion index was <1 in all S3 valves at the midframe, and the final dimensions, except the inflow and outflow of the 29 mm S3, were smaller than the nominal areas.A greater expansion of the 29 mm S3 may reflect the higher volume of fluid added and the percentage of undersizing.Despite this, 30-day echocardiography showed no worsening PVL or transvalvular aortic regurgitation.A recent large-scale CT study showed that underexpanded valves predicted hypoattenuating leaflet thickening and all-cause mortality at 1 year. 6Our CT study suggests that balloon overfilling in EAU did not significantly overexpand S3 valves.Given that the 29 mm S3 has the tallest frame, it may be more amenable to overexpansion at the inflow and outflow, as shown in our study.We hypothesize that a more optimal valve expansion can be achieved with S3 TAVR, when undersizing the valve for the annular anatomy, adding volume to the delivery balloon during deployment, or postdilatation to achieve a more complete expansion.
Our single-center cohort is limited by small sample size and lack of core laboratory evaluation, and long-term follow-up is required before drawing conclusions about durable clinical and echocardiographic outcomes with our S3 implant strategy.However, to our knowledge, this is the first study to assess post-TAVR CT-derived geometry of overfilled balloon-expandable valves, and the fact that no valve became overexpanded may prompt further investigation into the current balloon-expandable TAVR sizing strategy to achieve optimal valve expansion.
In the future, the SAPIEN X4 system may facilitate more accurate expansion as deployment diameters in 0.5 mm increments will be available.

Declaration of competing interest
Gilbert H. L. Tang is a physician proctor, physician advisory board member and consultant for Medtronic, physician advisory board member and consultant for Abbott Structural Heart, physician advisory board member for Boston Scientific and JenaValve, consultant for NeoChord, and has received speakers' honoraria for Siemens Healthineers.Sahil Khera is a physician proctor and consultant for Medtronic, and a consultant for Abbott Structural Heart, Eastend Medical, and Terumo.Sahil Khera also serves on the speaker's board for Zoll Medical.
The other authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.