Clinical characteristics and predictors of recurrence from the Australia-New Zealand Spontaneous Coronary Artery Dissection (ANZ-SCAD) registry

Abstract Background Spontaneous coronary artery dissection (SCAD) is an increasingly recognised cause of acute coronary syndrome (ACS), particularly in young women. Our understanding of SCAD remains incomplete with limited prospective data on determinants of SCAD recurrence. Purpose We aimed to describe the clinical characteristics, incidence and predictors of SCAD recurrence and major adverse cardiovascular events (MACE) in patients with SCAD from a large, multicentre registry. Methods Observational, multi-centre prospective and retrospective cohort study recruiting patients with SCAD from 23 hospitals in Australia and New Zealand. Patients aged=>18 years with SCAD and an ACS were eligible for inclusion. Prospectively recruited patients gave their informed consent while a waiver of consent was granted for retrospectively recruited patients. An independent core laboratory adjudicated invasive coronary angiography images to confirm the diagnosis of SCAD. The primary outcome was SCAD recurrence, defined as de novo spontaneous dissection with new ACS symptoms and cardiac enzyme elevation, not due to extension of the index lesion. Cox proportional hazard models were used to evaluate the association between SCAD recurrence and predefined clinical variables. Results From a total 487 patients recruited, 423 (132 prospective and 291 retrospective) patients with SCAD confirmed on core laboratory review were included for analysis. Mean age was 52.4±10.7 years, 89.7% were female and 73.1% were Caucasian. At discharge, 75.2% were on beta-blockers, 27.9% single antiplatelet and 61.9% dual antiplatelet (DAPT). At 15 (interquartile range 5-36) months median follow-up, SCAD recurrence occurred in 3.3%, with an overall MACE of 6.6%. On multivariate analysis, the presence of fibromuscular dysplasia (FMD) or other extra-cardiac vascular abnormalities [adjusted hazard ratio (HR) 5.63, 95% confidence interval (CI), 2.09-15.3, p<0.001], and past history of stroke (adjusted HR 7.99, 95% CI, 1.51-42.4, p=0.015) were associated with higher SCAD recurrence. Discharge beta-blockers was not independently associated with SCAD recurrence, while dual antiplatelet therapy that combined ticagrelor with aspirin was associated with a higher risk of recurrence (adjusted HR 2.47, 95% CI, 1.9-15.6, p=0.048). Conclusion SCAD recurrence comprised half of overall MACE in people with SCAD. The risk of SCAD recurrence was more than 5-fold higher in patients with FMD or other extra-cardiac vascular abnormalities. Dual-antiplatelet therapy that comprised ticagrelor and aspirin was associated with a higher risk of SCAD recurrence.