IFT05 - Long-term outcome evaluation of conservative management for extracranial carotid artery aneurysms: insights from the international Carotid Aneurysm Registry

Objectives: To assess the long-term outcomes of conservatively managed extracranial carotid artery aneurysms (ECAAs) within the international Carotid Aneurysm Registry (CAR).

Methods: The CAR is a prospective, multicenter, ongoing international registry. Since 2014, clinical symptoms, etiology, type of treatment and follow-up data have been registered in patients with primary ECAA. Growth was defined as a >2mm diameter increase over a minimum 12-month interval. Tailored follow-up and treatment, including antithrombotic therapy, adhered to local practice. The primary endpoint was the occurrence of ipsilateral ischemic cerebrovascular events, while secondary endpoints included assessments of mortality, aneurysm growth, rupture, and reintervention.

Results: Eight centers contributed 173 conservatively managed ECAA cases to the registry. The mean age was 56 years (SD 14.1), with 101 male patients (58.4%). The median ECAA diameter stood at 10mm (IQR 8-14). Antithrombotic medication was administered to 68.3% of patients. Median follow-up was 29 months (IQR 11-60). Stroke incidence was 1.7%, observed in three patients deemed unsuitable for surgical or endovascular intervention. Three patients (1.7%) experienced transient ischemic attacks (TIAs). Two of these patients received a change of medication and one patient had an endovascular procedure take place. All cerebrovascular events occurred in larger aneurysms (> third quartile, median 29mm, IQR 18.5-36.5) under antithrombotic therapy. The mortality rate reached 9.8%, with seventeen recorded fatalities. Of these, one was directly attributed to complications arising from a stroke associated with ECAA, while the remaining fatalities were unrelated to ECAA. Fifteen patients (8.7%) showed significant growth of the ECAA. One patient with observed growth underwent ECAA exclusion by surgery. One patient with observed growth had a TIA and was treated with endovascular techniques. One patient refused surgical treatment despite continuous growth. In the other 14 patients the growth stabilized and is still being monitored. Five patients (2.9%) formed a new ipsilateral or contralateral carotid aneurysm. No ruptures occurred.

Conclusions: Insights from the CAR indicate that conservative management appears to be a viable approach for the majority of primary ECAA cases. While rupture appears rare, the risk of ipsilateral stroke in smaller diameter ECAAs seems minimal.