Objective Spontaneous coronary artery dissection (SCAD) is an infrequent cause of acute coronary syndrome. Our aim was to assess adverse events at follow-up from a nationwide prospective cohort.

Methods The Spanish Registry on SCAD (SR-SCAD) included patients from 34 hospitals. All coronary angiograms were analysed by two experts. Those cases with doubts regarding the diagnosis of SCAD were excluded. The angiographic SCAD classification by Saw et al was followed. Major adverse cardiovascular and cerebrovascular event (MACCE) was predefined as composite of death, myocardial infarction, unplanned revascularisation, SCAD recurrence or stroke. All events were assigned by a Clinical Events Committee.

Results After corelab evaluation, 389 patients were included. Most patients were women (88%); median age 53 years (IQR 47–60). Most patients presented as non-ST-segment-elevation myocardial infarction (54%). A type 2 intramural haematoma (IMH) was the most frequent angiographic pattern (61%). A conservative initial management was selected in 78% of patients. At a median time of follow-up of 29 months (IQR 17–38), 46 patients (13%) presented MACCE, mainly driven by reinfarctions (7.6%) and unplanned revascularisations (6.2%). Previous history of hypothyroidism (HR 3.79; p<0.001), proximal vessel involvement (HR 2.69; p=0.009), type 2 IMH (HR 2.12; p=0.037) and dual antiplatelet therapy (DAPT) at discharge (HR 2.18; p=0.042) were independent predictors of MACCE.

Conclusions In this large prospective cohort of patients with SCAD, prognosis was overall favourable, with events mainly driven by reinfarctions or unplanned revascularisations. History of hypothyroidism, proximal vessel involvement, type 2 IMH and DAPT at discharge were associated with MACCE.

Trial registration number NCT03607981.