BACKGROUND AND AIMS
Spontaneous coronary artery dissection (SCAD) is an important cause of acute coronary syndrome (ACS) in predominantly young females. Treatment guidelines advocate conservative treatment of SCAD.1 The aim of this study was to conduct a first description of Swedish SCAD patients regarding the prevalence of risk factors, treatment, and prognosis.
MATERIALS AND METHODS
All patients with acute myocardial infarction (MI) registered in the Swedish Coronary Angiography and Angioplasty Register (SCAAR) from December 2015 until December 2017 were included. The index angiographies of the SCAD patients were re-evaluated by an independent angiographer at each centre. Patients with non-SCAD MI (n=31,670) were used for comparison.
SCAD was identified in 147 patients with MI (111 females; 36 males). The SCAD population was younger than the non-SCAD population, with a mean age of 52.9 (95% confidence interval [CI]: 51.0–54.9) years versus 68.5 (95% CI: 68.4–68.6) years, more often female (75.5% versus 31.9%), and presented with less risk factors (diabetes: 3.0% versus 21.4%; hypertension: 26.5% versus 59.4%; smoking: 38.1% versus 58.1%; statin therapy: 12.2% versus 39.1%; and previous MI: 10.9% versus 21.1%; p<0.001 for all comparisons). SCAD patients less frequently underwent percutaneous coronary intervention (40.1% versus 70.9%; p<0.001). SCAD patients who did undergo percutaneous coronary intervention received coronary stenting to a lesser extent compared to controls (30.6% versus 65.8%; p<0.001). There was no significant difference regarding treatment with aspirin (93.0% versus 89.7%; p=0.45) or double antiplatelet therapy (86.7% versus 84.2%; p=0.43) at discharge. SCAD patients did, however, receive less statin treatment (78.9% versus 91.5%; p<0.001). Analysis of composite outcome consisting of death, MI, and acute re-angiography showed no significant difference between the two groups in December 2017. Interestingly, data showed a higher rate of acute coronary re-angiography in SCAD patients in December 2018 (9.5% versus 4.5%; p<0.001). However, a composite outcome of death and reinfarction in December 2017 showed in the SCAD population was 5.4% versus 13.1% in controls (p=0.018).
With a current prevalence of 0.45% of all Swedish MI, data strongly suggest SCAD being an underdiagnosed condition with a prognosis resembling that of non-SCAD MI. Swedish SCAD patients are, as previous studies indicate, younger and harbour less cardiovascular risk factors than patients with traditional MI. The majority of SCAD patients were conservatively treated in contrast to patients with Type 1 MI. Nevertheless, 40% underwent coronary intervention, indicating overtreatment of SCAD during this time period.