Jander Nikolaus, Wienecke Susanne, Dorfs Stephan, Ruile Philipp, Neumann Franz-Josef, Pache Gregor, Minners Jan
Division of Cardiology and Angiology II, University Heart Center Freiburg Bad Krozingen, Bad Krozingen, Germany.
Section of Cardiovascular Radiology, Department of Radiology, University Hospital Freiburg, Bad Krozingen, Germany.
Echocardiography. 2018 Jun;35(6):777-784. doi: 10.1111/echo.13855. Epub 2018 Mar 9.
Two-dimensional, transthoracic echocardiography does not account for the noncircular anatomy of the left ventricular outflow tract (LVOT) and may therefore underestimate LVOT area. Fusion of computed tomography (CT)-derived LVOT area and Doppler-derived flow data has been proposed to improve assessment of aortic valve area (AVA) and classification of aortic stenosis severity. For hemodynamic reasons, effective AVA has to be smaller than anatomic AVA. The aim of the study was to test the "fusion approach" by comparing effective CT-derived AVA with anatomic AVA from CT planimetry.
Data of 244 consecutive patients (mean age 81 ± 5 years, 61% female) with aortic stenosis were retrospectively analyzed comparing effective AVA (calculated from the continuity equation using CT-LVOT and transthoracic Doppler measurements) with anatomic AVA based on CT planimetry. Substituting the LVOT area from transthoracic echocardiography (TTE) by the CT-LVOT resulted in an increase in AVA from 0.74 ± 0.15 to 0.92 ± 0.18cm² (P < .01), which was larger than anatomic AVA (0.82 ± 0.15cm²). Similar results were obtained based on planimetry from transesophageal echocardiography (TEE; AVA 0.79 ± 0.14cm², P < .01 vs CT-LVOT) and in the subgroup presenting with low-gradient severe aortic stenosis and preserved ejection fraction (n = 67, AVA from TTE 0.76 ± 0.09; from CT-LVOT 0.97 ± 0.14; CT planimetry 0.86 ± 0.12; TEE planimetry 0.82 ± 0.13cm²).
Fusion of CT-derived LVOT area with Doppler echocardiography results in a calculated effective AVA that is larger than the corresponding anatomic AVA. Therefore, adjustment of partition values may be warranted when using this approach.
二维经胸超声心动图未考虑左心室流出道（LVOT）的非圆形解剖结构，因此可能低估LVOT面积。有人提出将计算机断层扫描（CT）得出的LVOT面积与多普勒得出的血流数据相结合，以改善主动脉瓣面积（AVA）评估和主动脉瓣狭窄严重程度的分类。出于血流动力学原因，有效AVA必须小于解剖学AVA。本研究的目的是通过比较CT得出的有效AVA与CT平面测量法得出的解剖学AVA来检验“融合方法”。
回顾性分析244例连续的主动脉瓣狭窄患者（平均年龄81±5岁，61%为女性）的数据，比较有效AVA（使用CT-LVOT和经胸多普勒测量通过连续性方程计算得出）与基于CT平面测量法的解剖学AVA。用CT-LVOT替代经胸超声心动图（TTE）的LVOT面积，导致AVA从0.74±0.15增加到0.92±0.18cm²（P<.01），这大于解剖学AVA（0.82±0.15cm²）。基于经食管超声心动图（TEE）的平面测量也得到了类似结果（AVA 0.79±0.14cm²，与CT-LVOT相比P<.01），在低梯度严重主动脉瓣狭窄且射血分数保留的亚组中也是如此（n=67，TTE得出的AVA为0.76±0.09；CT-LVOT得出的为0.97±0.14；CT平面测量为0.86±0.12；TEE平面测量为0.82±0.13cm²）。
CT得出的LVOT面积与多普勒超声心动图相结合，得出的计算有效AVA大于相应的解剖学AVA。因此，使用这种方法时可能需要调整分界值。
