Diffuse Extra-Thoracic Vascular Disease in Nonsyndromic Thoracic Aortic Aneurysm and Dissection.

Patients with nonsyndromic thoracic aortic aneurysm and dissection (nsTAAD) may have systemic arterial involvement, but the distribution and clinical correlates of extrathoracic disease remain poorly defined. We conducted a retrospective cohort study of adults with nsTAAD at Mayo Clinic (2018-2024). Trained reviewers manually confirmed thoracic aortic dilation and all extrathoracic vascular lesions; syndromic, congenital, and fibromuscular dysplasia-related cases were excluded. Cross-sectional imaging availability was abstracted for the head or neck, chest, and abdomen or pelvis. Detection frequencies of nonthoracic aneurysm (nTA-A) were calculated among patients imaged in ≥1 extrathoracic territory, while nonaortic dissection (nTA-D) frequencies used the full cohort denominator. Group differences were assessed using Chi-square or t Tests, and logistic regression identified predictors of nTA-A. Among 3,989 patients (28.6% female), 82.0% had CT or MRI of ≥1 extrathoracic territory. nTA-A was detected in 443/3,270 (13.5%) and increased with age (7.4% at 18-30 years, 8.4% at 31 to 50 years, 18.3% at ≥51 years; p <0.001), with the greatest detection burden in the abdomen or pelvis followed by the head/neck. nTA-D occurred in 136/3,989 (3.4%) and also rose with age (0.7%, 2.2%, 4.9%; p <0.001). Hypertension and hyperlipidemia were independently associated with nTA-A (p ≤0.05). Patients with nTA-A or nTA-D had higher rates of heart failure, myocardial infarction, stroke, and mortality (all p ≤0.01). In conclusion, extrathoracic aneurysms and dissections are common in nsTAAD and increase with age, supporting careful clinical assessment with vigilant symptom monitoring and risk factor optimization, and providing a foundation for future studies to determine when broader vascular evaluation improves longitudinal risk stratification and outcomes.