Division of Vascular Surgery, University of Wisconsin School of Medicine and Public Health, Madison, Wisc.
Division of Vascular Surgery, University of Wisconsin School of Medicine and Public Health, Madison, Wisc.
J Vasc Surg. 2019 May;69(5):1379-1386. doi: 10.1016/j.jvs.2018.08.180. Epub 2018 Dec 28.
Sarcopenia, as assessed by computed tomography (CT)-based measurements of muscle mass, is an objective and patient-specific indicator of frailty, which is an important predictor of operative morbidity and mortality. Studies to date have primarily focused on psoas-defined sarcopenia, which may not be valid among patients with thoracic aortic disease. Using psoas sarcopenia as the reference for sarcopenia, the purpose of this study was to create and to validate a new thoracic-level method of measuring sarcopenia as a novel method to assess frailty among patients undergoing thoracic endovascular aortic repair.
Prospectively collected data of patients undergoing thoracic endovascular aortic repair for thoracic aortic dissection, aneurysm, or injury using a conformable thoracic graft were reviewed. Patients with preoperative abdominal and thoracic CT imaging were included. Thoracic muscle mass was measured on axial images at the T12 level using our newly established standardized computer-assisted protocol. Psoas sarcopenia was measured at the L3 level using standard methods. Optimal sex-specific diagnostic T12 measurements were determined by receiver operating characteristic (ROC) curve analysis. A subset of scans were reviewed in duplicate by two trained observers and intraobserver and interobserver reliability tested by intraclass correlation coefficient. Agreement between T12 and L3 sarcopenia was tested by Cohen κ (scale, 0-1).
There were 147 patients included for analysis, including 34 dissection, 80 trauma, and 33 aneurysm patients. ROC curve analysis yielded sarcopenic cutoff values of 106.00 cm/m for women and 110.00 cm/m for men at the T12 level. Based on ROC curve analysis, overall accuracy of T12 measurements was high (area under ROC curve, 0.91 for men and 0.90 for women). Quantitative interobserver and intraobserver reliability yielded excellent intraclass correlation coefficient values (>0.95). Qualitative interobserver reliability yielded nearly perfect Cohen κ values (>0.85). Qualitative intraobserver reliability of calculating sarcopenia at both the T12 and L3 levels was fair for both readers (0.361 and 0.288). There was additionally a general correlation between changes in muscle area at L3 with changes at T12 during 48 months.
Thoracic sarcopenia can be readily and reliably reproduced from CT-derived measurement of T12-level muscle area. This approach may be used as an alternative method to objectively define sarcopenia in patients without abdominal CT imaging. Future studies to assess the predictability of thoracic vs abdominal sarcopenia on postoperative outcomes will enhance the utility of these tools.
通过基于计算机断层扫描（CT）的肌肉质量测量评估的肌肉减少症是虚弱的客观和个体化指标，虚弱是手术发病率和死亡率的重要预测因素。迄今为止的研究主要集中在腰大肌定义的肌肉减少症上，而对于胸主动脉疾病患者，这种方法可能并不适用。本研究旨在创建并验证一种新的胸段测量肌肉减少症的方法，作为评估接受胸主动脉腔内修复术患者虚弱的一种新方法，该方法以腰大肌肌肉减少症作为肌肉减少症的参考。
回顾性分析了使用顺应性胸段移植物治疗胸主动脉夹层、动脉瘤或损伤的胸主动脉腔内修复术患者的前瞻性收集数据。纳入了术前有腹部和胸部 CT 成像的患者。使用我们新建立的标准化计算机辅助协议，在 T12 水平的轴位图像上测量胸肌质量。在 L3 水平使用标准方法测量腰大肌肌肉减少症。通过接收者操作特征（ROC）曲线分析确定最佳的性别特异性诊断 T12 测量值。对部分扫描进行了两次重复检查，由两名经过培训的观察者进行，并通过组内相关系数（ICC）测试了观察者内和观察者间的可靠性。通过 Cohen κ（等级，0-1）测试 T12 和 L3 肌肉减少症之间的一致性。
共纳入 147 例患者进行分析，其中 34 例为夹层，80 例为创伤，33 例为动脉瘤。ROC 曲线分析得出女性 T12 水平肌肉减少症的截断值为 106.00 cm/m，男性为 110.00 cm/m。基于 ROC 曲线分析，T12 测量的整体准确性较高（男性的曲线下面积为 0.91，女性为 0.90）。定量观察者间和观察者内可靠性产生了极高的 ICC 值（>0.95）。定性观察者间可靠性产生了近乎完美的 Cohen κ 值（>0.85）。两位观察者对 T12 和 L3 水平的肌肉减少症的计算的定性观察者内可靠性均为中等（0.361 和 0.288）。在 48 个月期间，L3 水平的肌肉面积变化与 T12 水平的变化之间还存在一般相关性。
T12 水平肌肉面积的 CT 衍生测量可以方便且可靠地重现胸段肌肉减少症。这种方法可作为一种替代方法，用于定义无腹部 CT 成像的患者的肌肉减少症。未来评估胸段与腹段肌肉减少症对术后结果的预测性的研究将提高这些工具的实用性。
