Nakabachi Masahiro, Iwano Hiroyuki, Murayama Michito, Nishino Hisao, Yokoyama Shinobu, Tsujinaga Shingo, Chiba Yasuyuki, Ishizaka Suguru, Motoi Ko, Okada Kazunori, Kaga Sanae, Nishida Mutsumi, Teshima Takanori, Anzai Toshihisa
Division of Clinical Laboratory and Transfusion Medicine, Hokkaido University Hospital, Kita-14, Nishi-5, Kita-ku, Sapporo, 060-8648, Japan.
Department of Cardiovascular Medicine, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita-15, Nishi-7, Kita-ku, Sapporo, 060-8638, Japan.
Heart Vessels. 2022 Apr;37(4):638-646. doi: 10.1007/s00380-021-01945-5. Epub 2021 Sep 25.
Although the echocardiographic effective orifice area (EOA) calculated using the continuity equation is widely used for the assessment of severity in aortic stenosis (AS), the existence of high flow velocity at the left ventricular outflow tract (LVOT) potentially causes its overestimation. The proximal isovelocity surface area (PISA) method could be an alternative tool for the estimation of EOA that limits the influence of upstream flow velocity. EOA was calculated using the continuity equation (EOA) and PISA method (EOA), respectively, in 114 patients with at least moderate AS. The geometric orifice area (GOA) was also measured using the planimetry method in 51 patients who also underwent three-dimensional transesophageal echocardiography. Patients were divided into two groups according to the median LVOT flow velocity. EOA could be obtained in 108 of the 114 patients (95%). Although there was a strong correlation between EOA and EOA (r = 0.78, P < 0.001), EOA was statistically significantly larger than EOA (0.86 ± 0.33 vs 0.75 ± 0.29 cm, P < 0.001). Both EOA and EOA similarly correlated with GOA (r = 0.70, P < 0.001 and r = 0.77, P < 0.001, respectively). However, a fixed bias, which is hydrodynamically supposed to exist between EOA and GOA, was not observed between EOA and GOA. In contrast, there was a negative fixed bias between EOA and GOA with smaller EOA than GOA. The difference between EOA and GOA was significantly greater with a larger EOA relative to GOA in patients with high LVOT flow velocity than in those without (0.16 ± 0.25 vs - 0.07 ± 0.10 cm, P < 0.001). In contrast, the difference between EOA and GOA was consistent regardless of the LVOT flow velocity (- 0.07 ± 0.12 vs - 0.07 ± 0.15 cm, P = 0.936). The PISA method was applied to estimate EOA in patients with AS. EOA could be an alternative parameter for AS severity grading in patients with high LVOT flow velocity in whom EOA would potentially overestimate the orifice area.
尽管使用连续性方程计算的超声心动图有效瓣口面积（EOA）被广泛用于评估主动脉瓣狭窄（AS）的严重程度，但左心室流出道（LVOT）处高流速的存在可能导致其被高估。近端等速表面积（PISA）法可能是一种估计EOA的替代工具，可限制上游流速的影响。分别使用连续性方程（EOA）和PISA法（EOA）对114例至少中度AS患者计算EOA。在51例同时接受三维经食管超声心动图检查的患者中，还使用面积测量法测量了几何瓣口面积（GOA）。根据LVOT流速中位数将患者分为两组。114例患者中有108例（95%）可获得EOA。虽然EOA与EOA之间存在强相关性（r = 0.78，P < 0.001），但EOA在统计学上显著大于EOA（0.86±0.33 vs 0.75±0.29 cm，P < 0.001）。EOA和EOA与GOA均具有相似的相关性（分别为r = 0.70，P < 0.001和r = 0.77，P < 0.001）。然而，在EOA与GOA之间未观察到流体动力学上认为应存在于EOA与GOA之间的固定偏差。相反，EOA与GOA之间存在负固定偏差，EOA小于GOA。与LVOT流速正常的患者相比，LVOT流速高的患者中，相对于GOA而言，EOA越大，EOA与GOA之间的差异就越显著（0.16±0.25 vs -0.07±0.10 cm，P < 0.001）。相反，无论LVOT流速如何，EOA与GOA之间的差异都是一致的（-0.07±0.12 vs -0.07±0.15 cm，P = 0.936）。应用PISA法估计AS患者的EOA。对于LVOT流速高的患者，在这些患者中EOA可能高估瓣口面积，EOA可能是AS严重程度分级的替代参数。
