OBJECTIVE: In the field of thoracoabdominal aortic aneurysm (TAAA) open surgical repair (OSR), some preoperative characteristics are established risk factors for adverse outcomes, whereas others are supposed to be relevant, but their role still need to be defined; among them, the presence of "shaggy aorta" (SA), an extensive and irregular atheroma within the aorta. The aim of this study is to report the results of a single-center large cohort of patients treated with OSR for TAAA with SA, comparing the outcomes with patients affected by TAAA without SA, and analyzing the impact of the scores for SA on the outcomes. METHODS: All consecutive patients receiving OSR for TAAA between 2012 and 2021 were retrospectively analyzed. Clinical data from patients with degenerative TAAA were included and analyzed for preoperative characteristics and postoperative outcomes; patients with ruptured TAAA, and patients with aortic dissection were excluded from the analysis. Patients with degenerative aortic aneurysm, thrombus measurement in non-aneurysmal aortic segments (≤40 mm), atheroma thickness ≥5 mm, and finger-like thrombus projection were included in the SA group, whereas the others were included in the non-shaggy aorta group (NSA group). The SA group and NSA group were compared using a propensity-matched comparison. Preoperative computed tomography scans of patients in the SA group were also stratified according to SA grading scores. RESULTS: A total of 58 patients with SA were identified (male, n = 43 [74.1%], mean age 70.1 ± 7.8 years) among 497 patients with TAAA treated with open surgical repair. After propensity matching, there were 57 patients in the SA group and 57 in the NSA group with correction of all differences in baseline characteristics. Patients in the SA group presented significantly higher in-hospital mortality (SA group, 14.0% vs NSA group, 3.5%; P = .047), postoperative acute renal failure (Risk, Injury, Failure, Loss of kidney function, and End-stage kidney disease [RIFLE], 3-5) (SA group, 21.1% vs NSA group, 5.3%; P = .013), and postoperative embolization (SA group, 28.1% vs NSA group, 8.8%; P = .008). Spinal cord ischemia and stroke rate were not significantly influenced by the presence of SA. In the SA group, 16 patients (27.6%) with end-organ embolization were compared with 42 patients (72.4%) without a documented embolization considering the grade of aortic "shagginess" and no significant difference was identified (P = .546). CONCLUSIONS: Despite a better knowledge of the SA disease, new classifications, and intraoperative adjuncts, TAAA patients with SA treated with OSR have worse postoperative outcomes if compared with patients without SA. The presence of SA is a risk factor itself, whereas the grade of "shagginess" seems not to impact on postoperative outcomes.