Systematic Review of the Influence of Anatomy and Aneurysm Type on Treatment Choice and Outcomes in Extracranial Carotid Artery Aneurysms.

Background: Extracranial carotid artery aneurysms (ECAA) are rare. Open surgery has traditionally been the treatment of choice, and endovascular management has recently been increasingly described. However, operative guidelines have not been defined.

Methods: A systematic review following PRISMA guidelines was performed to identify articles related to the symptoms, treatments, and outcomes of ECAAs. Included studies were further evaluated to identify distribution of treatment strategy based on anatomical location by Attigah classification (Type I-V) and aneurysmal type (true versus pseudoaneurysm).

Results: Twenty-eight retrospective reviews were included. A total of 906 patients (63% male) with 959 ECAAS were identified. The most common presenting symptoms included neck mass (45%) and neurological deficits (26%), while 218 (23%) were asymptomatic. True aneurysms accounted for 52% and pseudoaneurysms for 45% of cases. Of the 959 ECAAs, 750 were treated with open surgery, 85 with an endovascular procedure, and 124 conservatively. Perioperative complications of open surgery included cranial nerve injuries (CNI) in 9% (68), strokes in 4% (27), and death in 2% (18) of cases. There were no CNI, perioperative stroke, or perioperative mortality associated with 85 endovascular procedures; however, there was 1 case of restenosis (1%). Of the 124 patients treated conservatively, 3% (4) died as a result of the aneurysm. Twenty-two of 28 studies (688 ECAAs) reported anatomical location according to Attigah classification. The distribution of ECAAs were Type I (296/688; 43%), Type II (19/688; 3%), Type III (195/688; 28%), Type IV (76/688: 11%), and Type V (102/688; 15%). Eleven of 28 studies (241 ECAAs) reported treatment choice according to Attigah classification and revealed that the majority of Type I (82%), Type II (81%), Type III (91%), and Type IV (100%) ECAAs were treated via open surgery, while Type V ECAAs were evenly treated by open surgery and endovascular surgery. Twenty-three of 28 studies (780 ECAAs) reported treatment choice stratified by aneurysmal type. Of 417 true ECAAs, 88% were treated open surgically, 4% were treated endovascularly, and 8% were treated conservatively. Of 357 pseudoaneurysms, 67% were treated open surgically, 14% were treated endovascularly, and 19% were treated conservatively.

Conclusions: Most reported patients with ECAAs are symptomatic. Type I and III account for more than two-thirds of ECAAs, while true aneurysms account for roughly half. The vast majority of ECAAs have been treated surgically with results comparable to reoperative carotid endarterectomy. In selected patients, endovascular treatment has been very successful with no reported morbidity or mortality.