Author + information
- Saeko Sasuga1,
- Yutaka Tanaka2,
- Azuma Takahashi1,
- Kazuto Obama1,
- Yusuke Aoyama1,
- Umezu Mitsuo1,
- Shigeru Saito3 and
- Kiyotaka Iwasaki1
Reduction of paravalvular leak (PVL) after transcatheter aortic valve replacement (TAVR) is demanded for improving prognosis. However, the detailed mechanism of PVL has not been fully understood yet. We aimed to investigate the mechanism of PVL using a pulsatile flow simulator with patient-specific aortic valve models.
Based on pre-procedural CT data of six patients who had PVL after TAVR with 23-mm Sapien XT (Edwards Lifesciences), anatomically-identical aortic valve models with mechanically-matched calcified lesions were developed. The areas of the aortic valve annulus and transcatheter valve stent-frame after TAVR in the models were adjusted to those in the patients. The models of thoracic, abdominal, and iliofemoral arteries were also duplicated to simulate clinical TAVR procedure. After deployment of the transcatheter valves by transfemoral access with the same balloon inflation volume as in the clinical situations, mean forward flow and heart rate of each patient in two days after an operation was reproduced in the pulsatile flow simulator. Then, PVL were quantitatively measured using electromagnetic flow sensor. Moreover, an incompletely-apposed gap between the transcatheter valves and aortic valve annulus were examined using a micro-CT.
The PVL volumes of six patient-specific models in the pulsatile flow test were consistent with PVL grades by echocardiography in the patients (Table). The minimal cross-sectional area of the longitudinally incompletely-apposed gap had a strong correlation with the PVL volumes (R=0.89).
|Model||Paravalvular Leakage L/min||0.49||0.25||0.18||0.35||0.12||0.59|
|Total back flow L/min||0.86||0.68||0.63||0.73||0.47||0.90|
|Patient||TAVR AR Grade||Moderate to Severe||Mild||Mild||Moderate||Mild||Mild to Moderate|
This study revealed that the minimal cross-sectional area of the incompletely-apposed gap between the transcatheter valve and aortic valve annulus was associated with PVL volume.