https://doi.org/10.1007/s00392-025-02625-4
1LMU Klinikum der Universität München Herzchirurgische Klinik und Poliklinik München, Deutschland; 2LMU Klinikum der Universität München Klinik und Poliklinik für Radiologie München, Deutschland
Background: Rapid-deployment aortic valve replacement (RDAVR) and transcatheter aortic valve replacement (TAVR) have become important treatment options for aortic valve (AV) disease. However, the choice of a prosthesis for an elective AV replacement is usually based on the annulus diameter and the corresponding prosthesis size, as labelled by the manufacturer. Differences in the hemodynamic performance of different models of the same size, as well as the influence of patient-specific anatomical conditions are rarely considered.
Objectives: The lack of uniformity in size labels of the two therapeutic concepts, together with potentially adverse hemodynamic effects emphasize the need for a comprehensive comparison of commercially available TAVR and RADVR prostheses. This study investigated six state-of-the-art prosthetic heart valves implanted via transcatheter or surgical rapid-deployment technique, and their effect on thoracic aorta blood flow characteristics using an in vitro mock circulation setup and advanced imaging modalities.
Methods: Aortic phantoms were designed using segmentation and CAD software, and 3D printed using a flexible material. The valves were implanted and incorporated into a flow loop simulating pulsatile cardiac output and physiological pressure values. Qualitative and quantitative analysis was performed using complementary 4D flow magnetic resonance imaging (MRI) and vector (V) flow ultrasound (US). Parameters assessed included flow rate, wall shear stress (WSS), pressure gradient (PG), kinetic energy loss (EL), and effective orifice area (EOA). Flow patterns within the thoracic aorta were evaluated by streamline visualization.
Results: V flow US revealed systematic differences in flow rates between TAVR and RDAVR prostheses, except for the Intuity™ Elite 25 mm, which presented significantly lower flow velocities at the level of the sinotubular junction (p<0.0001). Post-hoc analysis in 4D flow software revealed localized regions of elevated WSS heterogeneously distributed without relevant differences between the TAVR and RDAVR prostheses. Notably, maximal WSS within the distal ascending aorta was found at 10.79±2.89 Pa for the Perceval™ L and therefore significantly higher compared to the Evolut™ Pro+ 26 mm (6.79±2.93 Pa, p=0.041). The RDAVR prostheses showed higher kinetic EL along the thoracic aorta in the Intuity™ Elite 23 mm and Perceval™ S compared to large-diameter models. In contrast, the larger TAVR valve was associated with a smaller kinetic EL of 9.44 µW/mm3 compared to the Sapien 3 Ultra™ 23 mm with a kinetic EL of 19.43 µW/mm3. EOA estimations obtained from 4D flow MRI ranged from 2.02 to 2.69 cm2 for RDAVR prostheses. The smaller TAVR model exhibited the smallest EOA at 1.71 cm2, while the 26 mm TAVR model was comparable to larger rapid-deployment valves. PG varied strongly between models and prosthesis types, reaching as high as 22.29 mmHg within the mid-ascending aorta for the Perceval™ L.
Conclusion: Despite their similarity in label-sizes, blood flow characteristics presented notable differences between the prostheses considered. The results emphasize that label-size standardization for future models based on an assessment of hemodynamic parameters is essential. Clinical studies in combination with the herein presented methodological approach could provide a foundation for interpreting clinical outcomes after TAVR or RDAVR and potentially reduce the risk of patient-prosthesis mismatch.