Background

Spontaneous coronary artery dissection (SCAD) is an acute, non-atheromatous, non-inflammatory, non-iatrogenic cause of myocardial infarction (MI) characterized by a spontaneous separation of the coronary vessel wall layers due to either vessel wall hematoma or an initial rift in the intimal-medial vessel wall. Little is known on its pathogenesis and, until a few years past, interventional cardiologists were little aware of the variations of its radiographic appearance. Specifically in Sweden, little research has been done on the demographics (incidence, prevalence, treatment and prognosis) of this disease and its diagnostic patterns.

Method

We utilised data from the SWEDEHEART registry to describe a Swedish SCAD population. We recruited a national cohort of acute SCAD patients to compare coronary computed tomography angiography (CCTA) as a non-invasive diagnostic modality against invasive coronary angiography (ICA) and further describe our angiographic findings. We investigated SCAD prevalence, diagnostic accuracy and sensitivity in women with MI <50 years between 2015-2023 from 3 Swedish hospitals, by comparing SWEDEHEART registry data and angiographic evaluations by two independent interventional cardiologists.

Results

We found an initial low prevalence of SCAD in Sweden. Compared to atherosclerotic (type 1) MI, SCAD patients were treated almost the same. SCAD patients had lower mortality but comparable morbidity and a higher incidence of unplanned repeat angiography than atherosclerotic MI patients. CCTA was less effective than ICA in identifying and locating acute SCAD, especially if distally located. There was significant underdiagnosing of SCAD in SWEDEHEART with an improving trend in accuracy during the reviewed period.

Conclusion

SCAD was initially underdiagnosed in Sweden, likely leading to an underestimation of its true prevalence. ICA remains the most reliable method for diagnosing SCAD since non-invasive CCTA could not demonstrate comparable precision. Since implementation of a SCAD variable in 2015, SCAD diagnosis in Sweden has improved.