Long-term clinical and mid-term radiographic follow-up of pure arterial malformations

Background: Pure arterial malformations (PAMs) are rare vascular lesions characterized by dilated, tortuous arterial loops without venous shunting. The natural history of PAMs remains unclear. We report the mid-term radiological and longer-term clinical outcomes of the largest series of patients with PAM. Methods: Retrospective review at a tertiary academic referral center for patients with a PAM. Follow-up clinical and radiological data were collected and analyzed for clinical symptoms and radiographic changes. Results: Twenty-five patients met the inclusion criteria. The mean age at presentation was 30.9 ± 14 years. Nineteen (76%) patients were female, and six (23.1%) were male. Eleven (44%) patients had ≥1 symptom at presentation, of which only 3 (12%) could be linked to PAM. The most common symptom was headache (n=8). PAMs involved a single vessel in 16 (64%) cases and ≥2 vessels in 9 cases (36%). Fifteen (60%) lesions were isolated to the anterior circulation compared to 6 (24%) in the posterior circulation. The most frequently involved vessel was the supraclinoid internal cerebral artery (36%). An associated saccular aneurysm was present in 32% of patients. Ten lesions were partially calcified. The mean radiographic and clinical follow-up was 21.9 ± 26.5 months and 44.6 ± 34.8 months, respectively. None of the patients developed new symptoms related to their lesion or radiographic progression over the duration of follow-up. Conclusions: PAMs are found most frequently in young, asymptomatic females. PAMs have a benign natural history and are best managed conservatively with serial imaging.