Comparison of Aortitis vs Non-Inflammatory Aortic Aneurysms Among Patients Who Undergo Open Aortic Aneurysm Repair

Background/Purpose: Distinguishing aortitis-induced aneurysms from more common non-inflammatory aortic aneurysms is difficult. Aortitis is often incidentally diagnosed upon histologic review after surgical repair of an aneurysm. Earlier detection of aortitis will allow for more prompt therapeutic intervention and possibly improve surgical outcomes. This study examined surgically diagnosed aortitis and identified patient characteristics and imaging findings associated with the disease.

Methods: This is a single-center, case-control study. Cases had biopsy-proven, newly-diagnosed, non-infectious aortitis following open aortic aneurysm surgical repair at the University of Pennsylvania Hospital System between 2012 and 2017. Controls were matched by year of open aortic aneurysm repair and lacked significant inflammation on pathology. Comorbidities, demographics, and laboratory prior to surgery were collected. Radiologic imaging (CT or MRI), including location of aneurysm, size, and rate of progression prior to surgery were also reviewed. The data was compared between aortitis and non-aortitis controls using Wilcoxon signed rank and chi-square or Fisher’s exact tests. Backward stepwise logistic regression was used to determine factors independently associated with aortitis.

Results: 62 patients were included: 31 patients with aortitis and 31 controls (Table 1). Compared to controls, patients with aortitis were less likely to have a history of coronary artery disease prior to surgery (10% vs 58%, p < 0.01), calcification or atheroma on imaging (27% vs 58%, p = 0.03), and calcific atherosclerosis on pathology (35% vs 69%, p < 0.01). Aortitis patients had significantly larger aneurysmal diameters at the time of surgery and, among patients with serial imaging, a faster rate of growth of the aneurysm. Multivariable analysis revealed that aortitis is independently associated with a larger diameter of the aneurysm, absence of calcifications or atheroma on imaging, and location of aneurysm in the ascending aorta (Table 2).

Conclusion: The study revealed that among patients who undergo open surgical repair of an aortic aneurysm, those with a larger aneurysm diameter, no prior history of coronary artery disease, or absence of atherosclerosis on imaging are more likely to have histologic evidence of aortitis. Patients with these risk factors may benefit from referral to a rheumatologist for further evaluation and assistance with post-operative management.