Pressure recovery downstream of the aortic valve constitutes an important factor affecting the calculation of pressure gradient (PG) across the valve and therefore the accuracy of the calculated aortic valve area. Some clinical studies hypothesized that stent and valve cusps design contribute to flow acceleration and Doppler-measured valve gradients across the balloon-expandable transcatheter aortic valve. This study aims at elucidating the physical mechanisms behind pressure recovery variations between Edwards SAPIEN 3 and Medtronic Evolut TAVs through the measurements of sensitive and precise axial pressure profiles. A 23 mm Edwards SAPIEN3 and a 26 mm Medtronic Evolut were deployed in a pulse duplicator. A Millar catheter was used to record 50 cycles of pressure data along the centerline of the valve chamber upstream and downstream of the valve. The peak PG obtained with SAPIEN at vena contracta (VC) is 18.83 ± 0.75 mmHg and after recovery, 9.56 ± 0.78 mmHg. For Evolut at VC, peak PG is 18.25 ± 0.63 mmHg and after recovery, 10.3 ± 0.57 mmHg. The differences in peak PG at VC and at the recovery were statistically significant (p < 0.001). With SAPIEN 3 at VC, the mean PG obtained is 10.11 ± 0.63 mmHg and after recovery 7.06 ± 0.46 mmHg. For Evolut, mean PG at VC is 10.45 ± 0.67 mmHg and after recovery 7.99 ± 0.61 mmHg. The differences between the mean PG between the two valves was not statistically significant at VC (p = 0.71) but significant post-recovery (p < 0.00001). While gradients at the VC are higher with the SAPIEN 3, the net gradient after pressure recovery is significantly lower compared to Evolut TAV. Efficiency of pressure recovery significantly depends on valve type due to stent interference with the recovering blood flow.

中文翻译：

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球囊扩张式和自扩张式经导管主动脉瓣之间压力恢复的差异。


主动脉瓣下游的压力恢复是影响整个瓣膜压力梯度 (PG) 计算的重要因素，因此影响主动脉瓣面积计算的准确性。一些临床研究假设支架和瓣膜尖端设计有助于球囊扩张经导管主动脉瓣上的血流加速和多普勒测量的瓣膜梯度。本研究旨在通过测量灵敏且精确的轴向压力分布来阐明 Edwards SAPIEN 3 和 Medtronic Evolut TAV 之间压力恢复变化背后的物理机制。脉冲复制器中部署了 23 毫米 Edwards SAPIEN3 和 26 毫米美敦力 Evolut。使用 Millar 导管沿着阀上游和下游的阀室中心线记录 50 个周期的压力数据。使用 SAPIEN 在收缩静脉 (VC) 处获得的峰值 PG 为 18.83 ± 0.75 mmHg，恢复后为 9.56 ± 0.78 mmHg。对于 VC 下的 Evolut，峰值 PG 为 18.25 ± 0.63 mmHg，恢复后为 10.3 ± 0.57 mmHg。 VC 时和恢复时的峰值 PG 差异具有统计学意义 (p < 0.001)。在 VC 下使用 SAPIEN 3，获得的平均 PG 为 10.11 ± 0.63 mmHg，恢复后为 7.06 ± 0.46 mmHg。对于 Evolut，VC 时的平均 PG 为 10.45 ± 0.67 mmHg，恢复后为 7.99 ± 0.61 mmHg。两个瓣膜之间的平均 PG 之间的差异在 VC 时不具有统计显着性 (p = 0.71)，但在恢复后显着 (p < 0.00001)。虽然 SAPIEN 3 的 VC 梯度较高，但压力恢复后的净梯度明显低于 Evolut TAV。由于支架会干扰恢复的血流，因此压力恢复的效率很大程度上取决于瓣膜类型。