ABSTRACT NUMBER: ESOC2026A2145 REVERSIBLE EXTRACRANIAL INTERNAL CAROTID ARTERY VASOSPASM: INSIGHTS FROM 45 IDIOPATHIC CASES

Abstract Background and aims Idiopathic isolated extra-cranial internal carotid artery vasospasm (iiecICAV) is a rare syndrome marked by spontaneous, segmental, and reversible vasoconstriction of the cervical ICA. Additional clinical, imaging, and laboratory data are needed to refine diagnosis and guide treatment. Methods We report five new cases of iiecICAV and conducted a PRISMA-compliant systematic review using PubMed, Google Scholar, and Web of Science (keywords: “carotid” AND “vasospasm” OR “spasm” OR “vasoconstriction” OR “constriction”). Forty cases were identified; protocol registered in PROSPERO (CRD42024605271). Results Among 45 cases (65% female), median age at symptom onset was 27 years (Interquartile Range-IQR: 16). Disease remained unilateral in 18%; others had bilateral or alternating vasospasms. Median follow-up was 2 years (IQR: 4), with a median of 5 recurrences (IQR: 14). Good functional outcome (modified Rankin Scale <3) was achieved in 90%. Medical therapies including antiplatelets (81%), anticoagulants (47%), glucocorticoids (27%), calcium channel blockers (66%) did not significantly alter recurrence or outcome. Invasive treatments were used in 60%, including ICA stenting (11), intra-arterial vasodilators (6), angioplasty (4), and stellate ganglion blockade (5). Recurrences ceased in 6 of 11 patients after ICA bifurcation stenting. In five patients with continued attacks, vasoconstriction occurred in the unstented subpetrosal ICA; targeted stenting in three led to complete resolution. Conclusions iiecICAV is a rare cause of ischemic stroke in young individuals. Despite varied treatment strategies, outcomes are generally favorable. Targeted stenting may reduce recurrence in anatomically specific cases Conflict of interest Ezgi Yilmaz: Nothing to disclose; Aneesh B. Singhal: Nothing to disclose; Okan Sokmen: Nothing to disclose, Emrah Aytac: Nothing to disclose, Hasan Huseyin Kozak: Nothing to disclose, Eylem Ozaydın Goksu: Nothing to disclose , Sinan Balcı: Nothing to disclose, Anil Arat: Nothing to disclose, Ethem Murat Arsava: Nothing to disclose, Mehmet Akif Topcuoglu: Nothing to disclose Topcuoglu1