背景:评估主动脉瓣狭窄(AS)的严重程度可能具有挑战性,特别是低梯度患者(LG,Δp<40mmHg)AS。
目的:本研究旨在提高使用新的功能指标-主动脉瓣系数(AVC)评估AS严重程度的准确性。AVC定义为平均跨瓣压降(Δp)与近端动压的比率(1/2×血液密度×VLVOT2;VLVOT:左心室流出道峰值速度)。
目标:AVC,从基本的流体动力学原理发展而来的,是评估AS严重程度的更好指标,因为它结合了VLVOT和下游压力恢复的平方。
方法:这项前瞻性研究纳入了47例接受TAVR的AS患者。使用心导管检查测量的Δp和超声心动图-多普勒衍生的VLVOT,对AVC进行了评估。获得了TAVR前后的压力-速度测量值,得到一个有78个数据点的数据集,包括专门链接到LGAS的32个数据点。进行线性回归分析以将AVC与Δp,VLVOT和主动脉瓣面积。进行Welch2样品t检验以比较AVC的平均值与主动脉瓣面积。
结果:在AVC和主动脉瓣面积之间观察到中度相关性(r=0.85),表明AVC可能是一个前瞻性指标。然而,LGAS患者的相关性降低(r=0.75),表明不和谐增加。比较左心室射血分数(LVEF)<50%和LVEF≥50%的LGAS患者的AVC和主动脉瓣面积,t检验显示AVC值与主动脉瓣面积(p=0.48)相比有显著差异(p<0.05)。
结论:AVC,一个新颖的索引,有可能改善AS严重程度的评估和治疗AS患者的临床决策。
结论:复杂的血流动力学,例如矛盾的“低流量低梯度(LG)”主动脉瓣狭窄(AS)可能难以诊断。目前,平均经瓣压降和流量来源的主动脉瓣面积评估AS严重程度.主动脉瓣系数(AVC)是一种新颖的指标,它结合了压降和流量测量来评估AS的严重程度。共有47名患者(72个数据点)接受TAVR研究。在LGAS患者中,比较左心室射血分数(LVEF)<50%和LVEF≥50%的t检验显示,与主动脉瓣面积(p=0.48)相比,AVC显着不同(p<0.05)。因此,AVC可能是一个更好的指标。
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 × VLVOT2; VLVOT: left ventricular outflow tract peak velocity).
OBJECTIVE: AVC, developed from fundamental fluid dynamic principles, is a better index for accessing AS severity as it incorporates square of VLVOT 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 VLVOT, 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, VLVOT 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).
CONCLUSIONS: AVC, a novel index, has the potential to improve assessment of AS severity and clinical decision making for treating patients with AS.
CONCLUSIONS: 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.