Blanke Philipp, Willson Alexander B, Webb John G, Achenbach Stephan, Piazza Nicolo, Min James K, Pache Gregor, Leipsic Jonathon
Department of Diagnostic Radiology, University Hospital Freiburg, Freiburg, Germany.
Department of Cardiology Namborn Hospital, Namborn, Australia.
J Cardiovasc Comput Tomogr. 2014 Jan-Feb;8(1):67-76. doi: 10.1016/j.jcct.2013.12.020. Epub 2014 Jan 12.
In transcatheter aortic valve replacement, prosthesis oversizing is essential to prevent paravalvular regurgitation. However, the estimated extent of oversizing strongly depends on the measurement used for annular sizing.
The aim was to investigate the influence of geometrical parameters for calculation of relative oversizing in transcatheter aortic valve replacement, reported as percentage in relation to the native annulus size, to standardize reporting.
Electrocardiogram-gated cardiac dual-source CT data of 130 consecutive patients with severe aortic stenosis (mean age, 81 ± 8 years; 56 men; mean aortic valve area, 0.67 ± 0.18 cm2) were included. Aortic annulus dimensions were quantified by means of planimetry that yielded area and perimeter at the level of the basal attachment points of the aortic cusps during systole. Area- and perimeter-derived diameters were calculated as DA = 2 × √(A/π) and DP = P/π. Hypothetical prosthesis sizing was based on DA (23-mm prosthesis for 19-22 mm; 26-mm prosthesis for 22-25 mm; 29-mm prosthesis for 25-28 mm). Relative oversizing for hypothetical prosthesis selection was calculated as percentage in relation to the native annulus size.
Mean annulus area was 492.12 ± 94.9 mm2 and mean perimeter was 80.1 ± 7.6 mm. DP was significantly larger than DA (25.5 ± 2.4 mm vs 24.9 ± 2.4 mm; P < .001). Mean maximum diameter was 28.1 ± 3.0 mm and mean minimal diameter was 22.8 ± 2.4 mm. Calculated eccentricity index [EI = 1 - minimal diameter/maximum diameter)] was 0.19 ± 0.06. Difference between DP and DA correlated significantly with EI (r = 0.67; P < .001). Relative oversizing was 10.2% ± 3.8% and 21.6% ± 8.4% by DA and area, and 7.8% ± 3.9% by both DP and perimeter.
For planimetric assessment of aortic annulus dimensions with CT, the percentage oversizing calculated strongly depends on the geometrical variable used for quantifying annular dimensions. Standardized nomenclature seems warranted for comparison of future studies.
在经导管主动脉瓣置换术中，人工瓣膜尺寸过大对于预防瓣周反流至关重要。然而，估计的尺寸过大程度在很大程度上取决于用于测量瓣环尺寸的方法。
旨在研究经导管主动脉瓣置换术中用于计算相对尺寸过大的几何参数的影响，以相对于天然瓣环尺寸的百分比形式报告，从而规范报告方式。
纳入130例连续的严重主动脉瓣狭窄患者的心电图门控心脏双源CT数据（平均年龄81±8岁；56例男性；平均主动脉瓣面积0.67±0.18 cm²）。通过平面测量法对主动脉瓣环尺寸进行量化，该方法可得出收缩期主动脉瓣叶基底部附着点水平的面积和周长。由面积和周长得出的直径分别计算为DA = 2×√(A/π)和DP = P/π。假设的人工瓣膜尺寸选择基于DA（19 - 22 mm选择23-mm人工瓣膜；22 - 25 mm选择26-mm人工瓣膜；25 - 28 mm选择29-mm人工瓣膜）。假设人工瓣膜选择的相对尺寸过大以相对于天然瓣环尺寸的百分比形式计算。
平均瓣环面积为492.12±94.9 mm²，平均周长为80.1±7.6 mm。DP显著大于DA（25.5±2.4 mm对24.9±2.4 mm；P <.001）。平均最大直径为28.1±3.0 mm，平均最小直径为22.8±2.4 mm。计算得出的偏心指数[EI = 1 - 最小直径/最大直径)]为0.19±0.06。DP与DA之间的差异与EI显著相关（r = 0.67；P <.001）。通过DA和面积计算得出的相对尺寸过大分别为10.2%±3.8%和21.6%±8.4%，通过DP和周长计算得出的相对尺寸过大为7.8%±3.9%。
对于通过CT进行主动脉瓣环尺寸的平面测量评估，计算得出的尺寸过大百分比在很大程度上取决于用于量化瓣环尺寸的几何变量。对于未来研究的比较，似乎有必要采用标准化的命名法。
