The effect of a smaller spacer in the PASCAL Ace on residual mitral valve orifice area

Background Mitral transcatheter edge-to-edge repair (M-TEER) is an established treatment for functional mitral regurgitation (FMR) associated with a risk of creating iatrogenic stenosis. Objectives To investigate the impact of the P10 and its larger spacer compared to the narrower Ace and its smaller spacer on reduction of mitral valve orifice area (MVOA) during M-TEER. Methods Consecutive patients undergoing M-TEER for treatment of severe FMR were screened retrospectively. Patients with a single PASCAL device implantation within the central segments of the MV leaflets, non-complex anatomy, and baseline MVOA ≥ 3.5cm 2 were selected. Intraprocedural transesophageal echocardiography was used to compare MVOA reduction with 3D multiplanar reconstruction and direct planimetry. Device selection did not follow a prespecified MVOA threshold. Results Seventy-two patients (81.0 years, IQR {74.3–85.0}) were included. In 32 patients, the P10 was implanted (44.4%). MR severity ( p = 0.66), MR reduction ( p = 0.73), and body surface area ( p = 0.56) were comparable. Baseline MVOA tended to be smaller in P10 patients with the larger spacer (5.0 ± 1.1 vs. 5.4 ± 1.3cm 2 , p = 0.18), however, residual MVOA was larger in these patients (2.7 ± 0.7 vs. 2.3 ± 0.6cm 2 , p = 0.03). Accordingly, relative MVOA reduction was significantly less in P10 patients (− 45.9 ± 7.6 vs. − 56.3 ± 7.0%, p < 0.01). Indirect annuloplasty was more pronounced in Ace patients whereas mean transmitral gradients were similar. Conclusion In FMR patients with non-complex anatomy, the larger spacer of the P10 maintains greater MVOA with similar MR reduction. Hence, the use of the PASCAL Ace device in patients with small MVOAs might correlate with a risk of both clinically relevant orifice reduction and even iatrogenic stenosis. Graphical Abstract Seventy-two patients treated for functional mitral regurgitation (FMR) with the narrower PASCAL Ace featuring a smaller spacer ( n = 40) or the broader P10 with a larger spacer ( n = 32) were included in this study. Using 3D TEE and multiplanar reconstruction for direct planimetry, mitral valve orifice areas (MVOA) were measured before and after device implantation. Only patients with central device positioning were included. The dimensions of the PASCAL device platform are shown as well. Note the larger space and broader design of the P10 compared to the PASCAL Ace. The difference in MVOA reduction amounted to 10%, which translates into roughly 0.5 cm 2 based on an average MV found in this study.