一种用于评估经导管主动脉瓣置换术（TAVR）患者主动脉瓣狭窄的新型功能指标——主动脉瓣系数：一项前瞻性初步研究。
A novel functional index, aortic-valve-coefficient, for assessing aortic-stenosis in patients undergoing TAVR: A prospective-pilot study.
作者信息
Manegaonkar Shreyash M, Sukhija Rishi, Effat Mohamed A, Rao Marepalli, Banerjee Rupak K
机构信息
Department of Mechanical and Materials Engineering, University of Cincinnati, Cincinnati, OH, USA.
Division of Cardiovascular Health and Disease, University of Cincinnati, Cincinnati, OH, USA.
出版信息
Cardiovasc Revasc Med. 2025 May;74:14-20. doi: 10.1016/j.carrev.2024.08.006. Epub 2024 Aug 22.
BACKGROUND
Evaluating the severity of aortic stenosis (AS) can be challenging, particularly in patients with low-gradient (LG, Δp < 40 mmHg) AS.
OBJECTIVE
This study aims to improve the accuracy of assessing severity of AS using a novel functional index- Aortic Valve Coefficient (AVC). The AVC is defined as ratio of mean transvalvular pressure-drop (Δp) to the proximal dynamic pressure (1/2 × blood density × V; V: left ventricular outflow tract peak velocity).
HYPOTHESIS
AVC, developed from fundamental fluid dynamic principles, is a better index for accessing AS severity as it incorporates square of V and downstream pressure recovery.
METHODS
This pilot prospective study enrolled 47 patients undergoing TAVR for AS. Using cardiac-catheterization-measured Δp and echocardiography-Doppler-derived V, AVC was evaluated. Pre- and post-TAVR pressure-velocity measurements were obtained, resulting in a dataset with 78 data points, including 32 data points specifically linked to LG AS. Linear regression analysis was performed to correlate AVC with Δp, V and aortic-valve-area. Welch 2-sample t-test was carried out to compare the means of AVC against aortic-valve-area.
RESULTS
Moderate correlation (r = 0.85) was observed between AVC and aortic-valve-area indicating AVC could be a prospective index. However, correlation decreased (r = 0.75) in LG AS patients, indicating increased discordancy. Comparing AVC and aortic-valve-area in LG AS patients with left ventricular ejection fraction (LVEF) < 50 % and LVEF ≥50 %, t-test showed that AVC values are significantly different (p < 0.05) as compared to aortic-valve-area (p = 0.48).
CONCLUSION
AVC, a novel index, has the potential to improve assessment of AS severity and clinical decision making for treating patients with AS.
CONDENSED ABSTRACT
Complex hemodynamics, such as paradoxical "low-flow low-gradient (LG)" Aortic stenosis (AS) can be difficult to diagnose. Currently, mean transvalvular pressure-drop and flow-derived aortic-valve-area assess AS severity. Aortic valve coefficient (AVC) is a novel index which combines both pressure-drop and flow measurements to assess the severity of AS. A total of 47 patients (72 data points) were studied undergoing TAVR. In LG AS patients, t-test comparing left ventricular ejection fraction (LVEF) < 50 % and LVEF ≥50 % showed that AVC are significantly different (p < 0.05) as compared to aortic-valve-area (p = 0.48). Therefore, AVC could be a better index.
背景
评估主动脉瓣狭窄（AS）的严重程度具有挑战性，尤其是对于低跨瓣压差（LG，Δp < 40 mmHg）的AS患者。
目的
本研究旨在通过一种新型功能指标——主动脉瓣系数（AVC）提高AS严重程度评估的准确性。AVC定义为平均跨瓣压差（Δp）与近端动态压力（1/2×血液密度×V；V：左心室流出道峰值速度）之比。
假设
基于基本流体动力学原理开发的AVC是评估AS严重程度的更好指标，因为它纳入了V的平方和下游压力恢复情况。
方法
这项前瞻性试点研究纳入了47例接受经导管主动脉瓣置换术（TAVR）治疗AS的患者。利用心导管测量的Δp和超声心动图多普勒得出的V来评估AVC。在TAVR前后进行压力-速度测量，得到一个包含78个数据点的数据集，其中包括32个与LG AS特别相关的数据点。进行线性回归分析以关联AVC与Δp、V和主动脉瓣面积。采用Welch双样本t检验比较AVC与主动脉瓣面积的均值。
结果
观察到AVC与主动脉瓣面积之间存在中度相关性（r = 0.85），表明AVC可能是一个有前景的指标。然而，在LG AS患者中相关性降低（r = 0.75），表明不一致性增加。在左心室射血分数（LVEF）< 50%和LVEF≥50%的LG AS患者中比较AVC和主动脉瓣面积，t检验显示与主动脉瓣面积相比（p = 0.48），AVC值存在显著差异（p < 0.05）。
结论
AVC作为一种新型指标，有潜力改善AS严重程度的评估以及AS患者治疗的临床决策。
摘要浓缩
复杂的血流动力学，如矛盾的“低流量低跨瓣压差（LG）”主动脉瓣狭窄（AS）可能难以诊断。目前，平均跨瓣压差和流量衍生的主动脉瓣面积用于评估AS严重程度。主动脉瓣系数（AVC）是一种新型指标，它结合了压差和流量测量来评估AS的严重程度。共研究了47例接受TAVR的患者（72个数据点）。在LG AS患者中，比较LVEF < 50%和LVEF≥50%的t检验显示，与主动脉瓣面积相比（p = 0.48），AVC存在显著差异（p < 0.05）。因此，AVC可能是一个更好的指标。
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