BACKGROUND: Spontaneous coronary artery dissection (SCAD) is an uncommon but increasingly recognised, important cause of acute coronary syndrome (ACS) primarily described in European and North American populations, with ethnic differences poorly understood. We investigated the ethnic distribution of patients with SCAD and ethnic differences in major adverse cardiovascular events (MACEs).
METHODS: This prospective and retrospective cohort study recruited adult patients with ACS and core-laboratory confirmed SCAD from 23 hospitals in Australia and New Zealand. Patients were analysed in four ethnic groups following the Australian Bureau of Statistics and Statistics New Zealand Standards for Ethnicity: white; Asian; Middle Eastern, North African, African (MENAA); and First Nations and Pacific Peoples. Predictors of MACEs were investigated with Cox proportional hazards models.
RESULTS: Of 622 patients with SCAD, 488 (78.5%) were white, 45 (7.2%) Asian, 29 (4.7%) MENAA, 48 (7.7%) First Nations and Pacific Peoples and 12 (1.9%) Other. Of the analysed cohort (mean age 52.3±10.5 years, 87.9% female), MENAA patients had higher rates of pregnancy-associated SCAD (24% vs 2% overall, p<0.001) and lower chest pain rates (86% vs 96% overall, p=0.008). First Nations and Pacific Peoples had higher rates of bystander atherosclerosis (25% vs 16% overall, p=0.02). Asian patients had higher rates of non-fibromuscular dysplasia extracardiac vascular abnormalities (16% vs 5% overall, p=0.008). MACE-free survival was similar across ethnic groups, and ethnicity was not an independent predictor of MACE when adjusted for potential confounders.
CONCLUSIONS: This study is the first to describe the diverse ethnic distribution of patients with SCAD in the Australian-New Zealand-SCAD registry. Important ethnic differences include higher rates of pregnancy-SCAD in MENAA patients, and higher rates of bystander atherosclerosis in First Nations and Pacific Peoples patients. No ethnic difference was seen in MACE-free survival following SCAD.