The Effect of Aneurysm Diameter on Perioperative Outcomes Following Endovascular Thoracoabdominal Aortic Aneurysm Repair.

Introduction: Endovascular repair of large-diameter infrarenal and complex abdominal aortic aneurysms has been associated with worse outcomes. Whether these associations also apply to thoracoabdominal aortic aneurysms remains unclear.

Methods: We identified all patients who underwent endovascular repair for intact thoracoabdominal aortic aneurysms between July 2010 and July 2024 in the Vascular Quality Initiative. A thoracoabdominal aortic aneurysm was defined as having a proximal aneurysm extent between zones 2 and 6, with at least one renal or visceral artery treated. Locally estimated scatterplot smoothing curves were used to visualize the relationship between preoperative aneurysm diameter and perioperative mortality, which informed the sex-specific definition of large aneurysms. Aneurysm size was categorized based on maximum diameter as follows (females/males): large (>60 mm/>65 mm), small (<50 mm/<55 mm), and medium (50-60 mm/55-65 mm). Perioperative outcomes were assessed using logistic regression models, and five-year mortality was evaluated using adjusted Kaplan-Meier methods and Cox regression. Both large and small aneurysms were compared with medium-sized aneurysms.

Results: A total of 1,309 patients were included; of these, 54% underwent repair for medium-sized aneurysms, 37% for large aneurysms, and 9.1% for small aneurysms. Median follow-up was 345 days. After adjustment, compared to medium-sized aneurysms, large aneurysms were associated with 31% higher odds of any perioperative complication (adjusted odds ratio [aOR], 1.31; 95% confidence interval [CI], 1.00-1.72; P=.046) and nearly twice the hazard of five-year mortality (adjusted hazard ratio [aHR], 1.94; 95% CI, 1.43-2.62; P<.01). The odds of perioperative mortality and in-hospital reintervention were similar between medium-sized and large aneurysms. No significant differences in perioperative outcomes or five-year mortality were observed between patients with small and medium-sized aneurysms.

Conclusions: Following endovascular repair for thoracoabdominal aortic aneurysms, compared with medium-sized aneurysms, large aneurysms (>60 mm in females, >65 mm in males) were associated with higher odds of any complication and higher five-year mortality. Patients with small aneurysms (<50 mm in females, <55 mm in males) demonstrated similar perioperative outcomes and five-year mortality compared to those with medium-sized aneurysms. These findings highlight the need to optimize management strategies for patients with large thoracoabdominal aortic aneurysms and emphasize the importance of improved screening programs to enable earlier detection.