Novel Morphological Features for Prediction of Distal Thoracic Aortic Enlargement after Thoracic Endovascular Aortic Repair of DeBakey IIIb Aortic Dissection.

Background: Identifying the risk factors predisposing to aortic enlargement after thoracic endovascular aortic repair (TEVAR) is needed for DeBakey IIIb aortic dissection. The aim of the study is to assess the novel morphological features for DeBakey IIIb aortic dissection in predicting distal thoracic aortic enlargement after TEVAR.

Methods: Sixty-seven patients who underwent TEVAR for DeBakey IIIb aortic dissection between January 2011 and December 2013 at our center were divided based on preoperative computer tomography angiography (CTA) features into 3 groups: I (n = 27) and III (n = 9), with true and false lumen, respectively, coursing closely along thoracic vertebral bodies and II, spiral configuration (n = 31). Distal thoracic aortic enlargement was determined using preoperative and postoperative CTA images.

Results: At median 12.2 (interquartile range, 4.3-26.6) months, 12 patients developed distal thoracic aortic enlargement, with estimated cumulative incidence tending to increase from categories I to III (P for trend < 0.01). Categories II and III versus I had more frequently concave location of primary entry tear (P < 0.01), larger dissection length and height index (L/Hi) (P = 0.05), and greater number of abdominal small branches involved preoperatively (P = 0.03), with otherwise similar baseline characteristics; and significantly greater total aortic diameter increase and lower false lumen regression up to 24 months, and lower true lumen expansion up to 12 months. In multivariable regression analysis, categories II and III were independently associated with distal thoracic aortic enlargement (hazard ratio, 19.95 [95% confidence interval, 2.14-186.09]; 41.23 [3.61-470.22], respectively) after adjustment for Society of Vascular Surgery score, preoperative maximum total aortic diameter, L/Hi, and number of abdominal small branches involved preoperatively.

Conclusions: The CTA-based morphological features described in this study might improve preoperative risk stratification of DeBakey IIIb aortic dissection, with categories II and III having higher risk of distal thoracic aortic enlargement after TEVAR.