Systematic review and meta-analysis of the clinical characteristics and outcomes of spontanous coronary artery dissection

Background: Spontaneous coronary artery dissection (SCAD) is an uncommon, non-iatrogenic, non-atherosclerotic cause of acute coronary syndrome. A lack of large prospective cohort studies and randomised controlled trials means that important questions about clinical characteristics and outcomes of patients with SCAD are yet to be fully answered. Method: A literature search of PUBMED, EMBASE and SCOPUS was undertaken up to and including the 23^rd January 2020. Studies reporting any cohort of 10 or more SCAD patients presenting with acute coronary syndrome, with appropriate clinical follow-up data were included in the analysis. Incidences of major adverse cardiovascular events (MACE), myocardial infarction and SCAD recurrence were meta-analysed using Poisson regression. Results: 19 studies, totalling p=2,172 patients, were included in the analysis. There was significant heterogeneity across the studies in all baseline characteristics and clinical outcomes. Prevalence of traditional cardiovascular risk factors was low; however, hypertension had a prevalence of 45% (95% CI; [35-54]) and fibromuscular dysplasia (FMD) was present in 68% (95% CI; [61-74]). Across all cohorts, the incidence of MACE in patients with SCAD was 7.80 per 100 person years (n=19, p=2172, 95% CI; [4.50-13.54]) and SCAD recurrence was 5.49 per 100 person years (n=13, p=1408, 95% CI; [3.75-8.02]). Conclusions: This meta-analysis confirms that SCAD is not an inconsequential cause of acute coronary syndrome and heralds the need for further prospective research to identify predictors of recurrent events and therapies to prevent them.