Characteristics and Prognosis of Abdominal or Thoracic Aortic Aneurysm Patients Admitted to Intensive Care Units After Surgical Treatment: A Multicenter Retrospective Observational Study

Abstract
Objective: To investigate the characteristics and prognosis of abdominal or thoracic aortic aneurysm (AAA or TAA) patients admitted to intensive care unit (ICU) postoperatively. Methods: Patients admitted to ICU postoperatively with a primary diagnosis of AAA or TAA were screened in the eICU Collaborative Research Database, which contained data from multiple ICUs throughout the continental United States in 2014 and 2015. Baseline characteristics and comorbidities and were investigated and factors associated with ICU mortality were explored using univariable logistic regression. Receiver operating characteristic (ROC) curve analysis was performed to evaluate the prognosis predictive performance of the widely used severity scoring system APACHE IVa. Results: A total of 974 patients including 677 AAA and 297 TAA patients admitted to ICU postoperatively were included. Compared with TAA, AAA patients had a significantly higher median age (72 versus 64 years, P< 0.001). 89.07% AAA and 84.51% TAA patients underwent elective surgery (P=0.046), 8.71% AAA and 31.99% TAA patients were with aortic dissection (P< 0.001), and 10.19% AAA and 2.36% TAA patients suffered from rupture of aortic aneurysm (P< 0.001). Hypertension requiring treatment was the most common comorbidity (57.31% for AAA and 61.95% for TAA). TAA patients had significantly higher ICU mortality (9.43% versus 2.36%, P< 0.001) than AAA. Several factors were found to be significantly associated with ICU mortality, including urgent surgery, with aortic dissection, rupture of aortic aneurysm, TAA, and a higher APACHE IVa score on ICU admission. APACHE IVa showed a good predictive performance for ICU mortality with an area under the ROC curve of 0.9176 (95% CI 0.8789– 0.9390). Conclusion: The prognosis of aortic aneurysm patients admitted to ICU postoperatively is yet to improve, and factors associated with prognosis are mainly related to the condition itself. APACHE IVa can be used for prognosis prediction.