Diagnostic Features of Infective Native Aortic Aneurysms:a Case-Control Study.

Background: Infective native aortic aneurysm (INAA) is a highly lethal disease that poses great challenges for the diagnosis. The Delphi consensus is the first consensus document and offered the diagnostic criteria of INAA. The previous research mainly compared INAA with published data. This case-control study aimed to compare clinical characteristics of INAA and non-infective aortic aneurysms (NIAA) to provide external verification of the diagnostic algorithm of INAA.

Methods: INAA patients between 2013 and 2022 were extracted and were further reviewed with the criteria of the consensus. NIAA patients were assigned to the randomly selected (RS) group at a ratio of 2:1 and the propensity score-matched (PSM) group at a ratio of 1:1. A case-control study was performed. A nomogram diagnostic model was constructed with the result of logistic regression.

Results: 87 cases were identified as INAA (6.6%). Mean age of INAA was 67.1 years (SD 9.8), younger than those with NIAA (P=.009). There was no significant difference in multiple aneurysms between INAA and NIAA (P=.12). Mural thrombus (n=45 versus 148) and calcification (n=36 versus 148) were negatively correlated with INAA. The sensitivity of the diagnostic algorithm was 98.9%, and the specificity was 75.9%. The area under curve of the diagnostic model was 0.97 and the concordance index was 0.97.

Conclusion: The diagnostic criteria in the Delphi consensus had a high sensitivity, while its specificity was not ideal. Whether multiple aneurysms can support the diagnosis of INAA remains to be further discussed. Mural thrombus and calcification can be the negative predictive factors of INAA. A new diagnostic model was proposed, and the nomogram model can identify INAA with high accuracy and discriminative ability.