Braley Katherine T, Tang Xinyu, Makil Elizabeth S, Borroughs-Ray Desiree, Collins Ronnie T
University of Arkansas for Medical Sciences, Little Rock, AR, USA.
Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, AR, USA.
Echocardiography. 2017 Jul;34(7):1029-1034. doi: 10.1111/echo.13565. Epub 2017 May 12.
Body surface area (BSA)-indexed Z-scores are used to assess the ascending aorta (AAo) and diagnose aortic dilation (AoD) in children. BSA is directly related to body weight and corresponds to body mass index (BMI). We hypothesized extremes in BMI alter interpretation of aortic size in pediatric patients with AoD.
We reviewed all echocardiograms with a diagnosis of AoD performed at our institution from January 2013 through June 2013. Those with an age <2 or >20 years, history of aortic root surgery, or inadequate images were excluded. The aorta was measured by standard methods at the sinus of Valsalva, sinotubular junction, and proximal AAo. Using subject age, height, and gender, hypothetical weights for each subject were calculated to provide BMIs corresponding to the 5th, 50th, 85th, and 95th percentiles. The derived weights were then used to determine hypothetical BSA, and Z-scores were calculated for the subject's aortic diameters in each BMI group.
A total of 153 patients met inclusion criteria. Mean age was 11.1±4.6 years (68% male). Mean height was 142.7±27.9 cm, mean weight 44.6±24.8 kg, and mean true BMI was the 62nd centile. Significant differences in all aortic dimension Z-scores were found among normal and underweight, overweight, and obese BMI groups (P<.001 for all comparisons), respectively.
Using current recommended methods, AoD will be missed in overweight and obese patients and overdiagnosed in underweight patients. For children of normal weight, a Z-score based on BSA may be reliable. As obesity rates increase, weight-independent Z-scores must be developed.
体表面积（BSA）指数化Z评分用于评估儿童升主动脉（AAo）并诊断主动脉扩张（AoD）。BSA与体重直接相关，且与体重指数（BMI）相对应。我们推测BMI的极端情况会改变小儿AoD患者主动脉大小的解读。
我们回顾了2013年1月至2013年6月在我们机构进行的所有诊断为AoD的超声心动图检查。排除年龄小于2岁或大于20岁、有主动脉根部手术史或图像不充分的患者。通过标准方法在主动脉瓣窦、窦管交界处和近端AAo测量主动脉。根据受试者的年龄、身高和性别，计算每个受试者的假设体重，以提供对应于第5、50、85和95百分位数的BMI。然后使用得出的体重来确定假设的BSA，并计算每个BMI组中受试者主动脉直径的Z评分。
共有153例患者符合纳入标准。平均年龄为11.1±4.6岁（68%为男性）。平均身高为142.7±27.9厘米，平均体重44.6±24.8千克，平均实际BMI为第62百分位数。在正常体重、体重过轻、超重和肥胖BMI组之间，所有主动脉尺寸Z评分均存在显著差异（所有比较P<0.001）。
使用当前推荐的方法，超重和肥胖患者会漏诊AoD，体重过轻患者会被过度诊断。对于正常体重的儿童，基于BSA的Z评分可能是可靠的。随着肥胖率的增加，必须开发与体重无关的Z评分。
