Impact of Flow Status on Effective Orifice Area in Transcatheter Heart Valves: A COMPARE-TAVI 1 Substudy

The aim of this study was to study the impact of flow status on effective orifice area (EOA) in patients treated with the balloon-expandable Myval and Sapien transcatheter heart valves (THVs).

We collected the core laboratory-measured EOA, mean and peak gradients, Doppler velocity index (DVI), and stroke volume index (SVi) from the 30-day echocardiograms in patients treated with the balloon-expandable Myval and Sapien THVs in the COMPARE-TAVI 1 trial. Patients were stratified according to flow into low flow (SVi <35 mL/m²), normal flow (SVi 35-50 mL/m²), and high flow (SVi >50 mL/m²).

A total of 1,031 patients were included in COMPARE-TAVI 1. Myval THVs (20.0-32.0 mm) exhibited overall higher mean EOA and lower mean gradients (1.99 ± 0.55 cm², 9.46 ± 3.84 mm Hg) compared to Sapien THVs (20-29 mm; 1.81 ± 0.56 cm², 11.47 ± 4.47 mm Hg). Compared to normal-flow patients, low-flow patients exhibited smaller EOA (P < .001) and lower DVI (P < .001) in all valve sizes irrespective of THV platform, while high-flow patients had larger EOA (P < .001) and higher DVI (P < .001). Female sex was associated with lower stroke volume, resulting in lower mean and peak gradients independent of valve size and platform (P < .001).

The study indicates that EOA may be underestimated after TAVI in patients with low-flow status, which can impact the assessment of prosthesis-patient mismatch.