Abstract 4143164: Autoimmunity and Sex Inform Clinical Outcomes of Non-Aortic Arterial Dissections

Background: Non-aortic arterial dissections (NAAD) are increasingly diagnosed on imaging but natural history of disease in women and men is poorly understood, and long-term outcomes are still not well-defined. NAAD pathobiology is broadly subdivided as either rheumatologic or non-rheumatologic, but whether this binary classification is relevant for clinical outcomes is not clear. Methods: Utilizing the TriNetX Research Collaborative Network containing nearly 90 million deidentified electronic health records, patients aged 18 years or older diagnosed with NAAD between January 1, 2014 to May 8, 2024 were stratified into two cohorts based on presence or absence of a diagnosed rheumatologic condition. Patients were identified using ICD-9/10 codes to include any code for a large or medium vessel arterial dissection and/or rheumatologic condition; patients with aortic dissection codes were excluded. Following propensity score matching for covariates, groups were analyzed for all-cause mortality and major adverse cardiovascular events (MACE) (stroke, cardiac arrest, acute myocardial infarction, heart failure) after 1 year and 5 years using Kaplan-Meier survival analysis with log-rank testing and Cox proportional hazard model. Results: A total of 64,984 patients were identified to have an ICD-9/10 code for a NAAD; 60,196 had no associated rheumatologic condition and 4,698 had a co-morbid rheumatologic ICD-9/10 code. Prior to propensity matching, NAAD patients with rheumatologic conditions were more likely to be older (59.6 vs 54.5 years), female (63% vs. 47%), and have a greater prevalence of cardiovascular risk factors (p < 0.001 for all). After propensity matching, NAAD patients with rheumatologic conditions had higher all-cause mortality at 1 year (hazard ratio [HR] with 95% confidence intervals: 1.34 [1.12-1.60]) and 5 years (HR: 1.21 [1.07-1.38]) compared to non-rheumatologic NAAD patients. Non-rheumatologic dissection patients exhibited sex-biased outcomes, with mortality (1-year HR: 1.26 [1.17-1.35], 5-year HR: 1.25 [1.18-1.33]), MACE (5-year HR: 1.08 [1.01-1.15]), and need for vascular procedures (2.5% versus 2.05%, p < 0.001) more likely to occur in men than women; conversely, rheumatologic dissection patients did not show sex-based differences. Conclusions: The presence of co-morbid rheumatologic conditions is associated with greater mortality in patients with NAAD. Sex is an important modifier of clinical outcomes in non-rheumatologic dissection patients.