Myocardial infarction during giant cell arteritis: A cohort study.

BACKGROUND:Cardiovascular risk is increased in giant cell arteritis (GCA). We aimed to characterize myocardial infarction (MI) in a GCA cohort, and to compare the GCA and non-GCA population affected by MI. METHODS:In patients with a biopsy-proven diagnosis of GCA between 1 January 2001 and 31 December 2016 in Côte D'Or (France), we identified patients with MI by crossing data from the territorial myocardial infarction registry (Observatoire des Infarctus de Côte d'Or) database. Five controls (non-GCA + MI) were paired with one case (GCA + MI) after matching for age, sex, cardiovascular risk factors and prior cardiovascular disease. MI were characterized as type 1 MI (T1MI), resulting from thrombus formation due to atherothrombotic disease, or type 2 MI (T2MI), due to a myocardial supply/demand mismatch. GCA-related MI was defined as MI occurring within 3 months of a GCA flare (before or after). RESULTS:Among 251 biopsy-proven GCA patients, 13 MI cases were identified and paired with 65 controls. MI was GCA-related in 6/13 cases, accounting for 2.4% (6/251) of our cohort. T2MI was more frequently GCA-related than GCA-unrelated (80% vs. 16.7%, p = 0.080), and GCA diagnosis was the only identified triggering factor in 75% of GCA-related T2MI. GCA-unrelated MI were more frequently T1MI and occurred in patients who had received a higher cumulative dose of prednisone (p = 0.032). GCA was not associated with poorer one-year survival. CONCLUSIONS:GCA-related MI are mainly T2MI probably caused by systemic inflammation rather than coronaritis. GCA-unrelated MI are predominantly T1MI associated with atherothrombotic coronary artery disease.