Prediction of rupture risk in abdominal aortic aneurysm during observation: Wall stress versus diameter
Prediction of rupture risk in abdominal aortic aneurysm during observation: Wall stress versus diameter
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DOI：
10.1067/mva.2003.213
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发表时间：
2003-04-01
影响因子：
4.3
通讯作者：
Kennedy, FE
中科院分区：
文献类型：
--
作者：
Fillinger, MF;Marra, SP;Kennedy, FE
目标。我们之前的研究表明，体内计算的腹主动脉瘤（AAA）壁应力峰值在破裂时高于选择性修复时。本研究的目的是分析观察患者随时间的破裂风险。对计划观察至少6个月的AAA患者的CT扫描结果进行分析。通过CT数据、三维计算机建模、有限元分析（描述动脉瘤壁行为的非线性超弹性模型）和观察期间的血压，计算确定AAA壁在体内的应力分布。分析包括103例患者和159个CT扫描（平均随访，每台CT 14±2个月）。42例患者在不干预的情况下观察至少1年（平均随访28 +/- 3个月）。39例患者在1年内进行了选择性修复，22例患者（平均在CT后6个月）因破裂（n = 14）或急性剧烈疼痛进行了紧急修复。初始直径有显著差异(观察值，4.9。+ / - cm;选择性修复，5.9 +/- 1 cm；紧急修复，6.1 +/- 2 cm；P < 0.0001)和初始峰值壁应力分别为38 +/- 1 N/cm(2)、42 +/- 2 N/cm(2)、58 +/- 4 N/cm(2)；P < 0.0001)，但峰值壁应力似乎可以更好地区分后来需要紧急修复的患者（选择性修复与紧急修复：直径，差异3%，P = 0.5；应力，差异38%，P < 0.0001）。预测破裂的受试者工作特征（ROC）曲线对峰值壁应力的敏感度为94%，特异度为81%，准确度为85% [44 N/cm(2)阈值]]优于直径（分别为81%，70%，73%[最优5.5 cm阈值]）。通过比例风险分析，峰值壁应力（相对风险，25x）和性别（相对风险，3x）是唯一显著的独立预测破裂的因素。对于观察中的AAAs，峰值AAAs壁应力似乎优于直径，以区分将经历灾难性后果的患者。与破裂相关的壁面应力升高不仅仅是破裂时间附近的急性事件。
Objectives. We previously showed that peak abdominal aortic aneurysm (AAA) wall stress calculated for aneurysms in vivo is higher at rupture than at elective repair. The purpose of this study was to analyze rupture risk over time in patients under observation.Methods. Computed tomography (CT) scans were analyzed for patients with AAA when observation was planned for at least 6 months. AAA wall stress distribution was computationally determined in vivo with CT data, three-dimensional computer modeling, finite element analysis (nonlinear hyperelastic model depicting aneurysm wall behavior), and blood pressure during observation.Results. Analysis included 103 patients and 159 CT scans (mean follow-up, 14 +/- 2 months per CT). Forty-two patients were observed with no intervention for at least I year (mean follow-up, 28 +/- 3 months). Elective repair was performed within 1 year in 39 patients, and emergent repair was performed in 22 patients (mean, 6 I month after CT) for rupture (n = 14) or acute severe pain. Significant differences were found for initial diameter (observation, 4.9. +/- cm; elective repair, 5.9 +/- 1 cm; emergent repair, 6.1 +/- 2 cm; P < .0001) and initial peak wall stress (38 +/- 1 N/cm(2), 42 +/- 2 n/cm(2), 58 +/- 4 N/cm(2), respectively; P < .0001), but peak wall stress appeared to better differentiate patients who later required emergent repair (elective vs emergent repair: diameter, 3% difference, P = .5; stress, 38% difference, P < .0001). Receiver operating characteristic (ROC) curves for predicting rupture were better for peak wall stress (sensitivity, 94%; specificity,81%; accuracy, 85% [with 44 N/cm(2) threshold]) than for diameter (81%, 70%, 73%, respectively [with optimal 5.5 cm threshold). With proportional hazards analysis, peak wall stress (relative risk, 25 X) and gender (relative risk, 3 X) were the only significant independent predictors of rupture.Conclusions. For AAAs under observation, peak AAA wall stress seems superior to diameter in differentiating patients who will experience catastrophic outcome. Elevated wall stress associated with rupture is not simply an acute event near the time of rupture.