Fillinger Mark F, Racusin Jessica, Baker Robert K, Cronenwett Jack L, Teutelink Arno, Schermerhorn Marc L, Zwolak Robert M, Powell Richard J, Walsh Daniel B, Rzucidlo Eva M
Section of Vascular Surgery, Dartmouth-Hitchcock Medical Center, One Medical Center Drive, Lebanon, NH 03750, USA.
J Vasc Surg. 2004 Jun;39(6):1243-52. doi: 10.1016/j.jvs.2004.02.025.
The purpose of this study was to analyze anatomic characteristics of patients with ruptured abdominal aortic aneurysms (AAAs), with conventional two-dimensional computed tomography (CT), including comparison with control subjects matched for age, gender, and size.
Records were reviewed to identify all CT scans obtained at Dartmouth-Hitchcock Medical Center or referring hospitals before emergency AAA repair performed because of rupture or acute severe pain (RUP group). CT scans obtained before elective AAA repair (ELEC group) were reviewed for age and gender match with patients in the RUP group. More than 40 variables were measured on each CT scan. Aneurysm diameter matching was achieved by consecutively deleting the largest RUP scan and the smallest ELEC scan to prevent bias.
CT scans were analyzed for 259 patients with AAAs: 122 RUP and 137 ELEC. Patients were well matched for age, gender, and other demographic variables or risk factors. Maximum AAA diameter was significantly different in comparisons of all patients (RUP, 6.5 +/- 2 cm vs ELEC, 5.6 +/- 1 cm; P <.0001), and mean diameter of ruptured AAAs was 5 mm smaller in female patients (6.1 +/- 2 cm vs 6.6 +/- 2 cm; P =.007). Two hundred patients were matched for diameter, gender, and age (100 from each group; maximum AAA diameter, 6.0 +/- 1 cm vs 6.0 +/- 1 cm). Analysis of diameter-matched AAAs indicated that most variables were statistically similar in the two groups, including infrarenal neck length (17 +/- 1 mm vs 19 +/- 1 mm; P =.3), maximum thrombus thickness (25 +/- 1 mm vs 23 +/- 1 mm, P =.4), and indices of body habitus, such as [(maximum AAA diameter)/(normal suprarenal aorta diameter)] or [(maximum AAA diameter)/(L3 transverse diameter)]. Multivariate analysis controlling for gender indicated that the most significant variables for rupture were aortic tortuosity (odds ratio [OR] 3.3, indicating greater risk with no or mild tortuosity), diameter asymmetry (OR, 3.2 for a 1-cm difference in major-minor axis), and current smoking (OR, 2.7, with the greater risk in current smokers).
When matched for age, gender, and diameter, ruptured AAAs tend to be less tortuous, yet have greater cross-sectional diameter asymmetry. On conventional two-dimensional CT axial sections, it appears that when diameter asymmetry is associated with low aortic tortuosity, the larger diameter on axial sections more accurately reflects rupture risk, and when diameter asymmetry is associated with moderate or severe aortic tortuosity, the smaller diameter on axial sections more accurately reflects rupture risk. Current smoking is significantly associated with rupture, even when controlling for gender and AAA anatomy.
本研究旨在利用传统二维计算机断层扫描（CT）分析腹主动脉瘤（AAA）破裂患者的解剖特征，并与年龄、性别和大小匹配的对照受试者进行比较。
回顾记录，以识别在达特茅斯-希区柯克医疗中心或转诊医院因破裂或急性剧痛而进行急诊AAA修复前获得的所有CT扫描（RUP组）。对择期AAA修复前获得的CT扫描（ELEC组）进行回顾，以使其与RUP组患者的年龄和性别相匹配。在每次CT扫描上测量40多个变量。通过连续删除最大的RUP扫描和最小的ELEC扫描来实现动脉瘤直径匹配，以防止偏差。
对259例AAA患者的CT扫描进行了分析：122例RUP患者和137例ELEC患者。患者在年龄、性别和其他人口统计学变量或风险因素方面匹配良好。在所有患者的比较中，AAA最大直径有显著差异（RUP组为6.5±2cm，ELEC组为5.6±1cm；P<0.0001），女性破裂AAA的平均直径小5mm（6.1±2cm对6.6±2cm；P = 0.007）。200例患者在直径、性别和年龄方面进行了匹配（每组100例；AAA最大直径为6.0±1cm对6.0±1cm）。对直径匹配的AAA分析表明，两组中的大多数变量在统计学上相似，包括肾下颈部长度（17±1mm对19±1mm；P = 0.3）、最大血栓厚度（25±1mm对23±1mm，P = 0.4）以及身体形态指标，如[（AAA最大直径）/（正常肾上腺上主动脉直径）]或[（AAA最大直径）/（L3横径）]。控制性别后的多变量分析表明，破裂的最显著变量是主动脉迂曲（优势比[OR]为3.3，表明无或轻度迂曲时风险更高）、直径不对称（长短轴相差1cm时OR为3.2）和当前吸烟（OR为2.7，当前吸烟者风险更高）。
当在年龄、性别和直径方面匹配时，破裂的AAA往往迂曲程度较小，但横截面直径不对称性更大。在传统二维CT轴位图像上，当直径不对称与主动脉低迂曲相关时，轴位图像上较大的直径更准确地反映破裂风险；当直径不对称与中度或重度主动脉迂曲相关时，轴位图像上较小的直径更准确地反映破裂风险。即使在控制性别和AAA解剖结构后，当前吸烟也与破裂显著相关。
