OBJECTIVE: As endovascular interventions become safer and their use more prevalent for treating extracranial pseudoaneurysms, fewer pseudoaneurysms are treated with medical therapy alone. This study aimed to assess the indications for intervention and the safety of medical management. METHODS: A dual-center retrospective analysis was conducted on patients diagnosed with extracranial carotid and vertebral pseudoaneurysms between December 2006 and June 2023. RESULTS: Of 145 pseudoaneurysms, 121 (83%) received medical therapy, 22 (15%) were treated endovascularly, and 2 (1.4%) were treated with open surgery. In the medical group, there were 2 (1.9%) complications, one unrelated to the pseudoaneurysm. In the intervention group, there were 3 (16%) complications, with 1 patient requiring two retreatments and sacrifice of the vessel. Major trauma (OR 4.0, 95% CI 1.3-14
p = 0.02), use of digital subtraction angiography as the initial imaging modality (OR 9.8, 95% CI 2.5-42
p <
0.01), and a maximum lesion diameter >
6 mm (OR 5.3, 95% CI 1.4-25
p = 0.03) proved to be significant in the decision to intervene. At a median follow-up of 18.1 months, 94.7% of the lesions treated with intervention healed completely compared with 19% of aneurysms in the medical group. Among those medically managed that did not resolve, the median change in diameter was -0.4 mm (IQR -1.8 to 0.4 mm). Age ≤ 50 years and aneurysm maximum diameter ≤ 6 mm predicted healing at follow-up in the medical group with 92% specificity and 65% sensitivity (area under the curve 0.87). At follow-up, 98% of patients were functionally independent (modified Rankin Scale score ≤ 2). CONCLUSIONS: Medical management alone is safe for most extracranial pseudoaneurysms, resulting in significantly fewer complications than endovascular intervention. Maximum diameter ≤ 6 mm and age ≤ 50 years were significant predictors of pseudoaneurysm resolution with medical therapy alone. Lesions that do not heal do not cause further symptoms or require additional intervention.