Ab1306 Different Giant Cell Arteritis Phenotypes May Present Distinct Types of Ischemic Complications

Background: The onset of ischemic complications (IC) in patients with giant cell arteritis (GCA) has traditionally been associated with the cranial GCA phenotype. However, the progressive use of imaging techniques in GCA is expanding the diagnosis of large vessel (LV) GCA, but the association with this phenotype of the disease have not been fully described. Objectives: To determine if clinical or vascular ultrasound (US) findings at the onset of GCA are associated with different types of IC. Methods: Retrospective observational study of patients referred to the US fast-track clinics of two centers with GCA clinical confirmation over 4-years. All patients underwent baseline US examination of cranial and extracranial arteries (carotid, subclavian and axillary) at the time of referral. IC was defined as the occurrence of acute anterior ischemic optic neuropathy (AION) or non-AION (including stroke, acute coronary syndrome, pulmonary embolism or peripheral artery disease) within 3 months after diagnosis, excluding other potentially implicated causes. Chi-squared and analysis of variance were performed to compare epidemiological, clinical characteristics, and US finding according to the presence of IC. Results: A total of 42 (22.9%) patients over 188 patients with GCA clinical confirmation evaluated at our fast-track clinic had an IC within 3 months since diagnosis, 24 (12.8%) an AION and 19 (10.1%) a non-AION IC. Patient characteristics and US findings according to the presence and type of IC are shown in Table 1. Patients with AION showed more frequently findings of US cranial involvement versus patients with non-AION IC and without IC (100% vs 63.2% vs 79.3%; p= 0.009). Patients with AION presented less frequently signs of US LV-GCA (25% vs 63.2% vs 55.2%; p=0.014), previous polymyalgia rheumatica (PMR) (8.3 % vs 31.6% vs 31%; p=0.049) or concomitant PMR symptoms at the time of diagnosis versus patients with non-AION IC and without IC (20.8 % vs 47.4% vs 53.1%; p=0.014). In contrast, patients with non-AION IC presented more frequently positive LV-GCA US findings vs the other two groups (63.2% vs 25% vs 55.2%; p=0.014). No significant differences were observed in the frequency of previous PMR diagnosis (30.6% vs. 25.6%; p=0.695) or PMR symptoms at the time of diagnosis (51% vs. 45.6%; p=0.454) between patients with and without LV-GCA US. Conclusion: Different GCA phenotypes may present distinct types of ischemic complications. Predominantly US cranial-GCA patients have more frequently AION, while predominantly US LV-GCA patients with previous or concomitant PMR have more frequently non-AION IC. REFERENCES: NIL. Table 1. Baseline clinical, laboratory and imaging findings according to presence and type of ischemic complications. Acknowledgements: NIL. Disclosure of Interests: None declared.