No abstract

AimsSpontaneous coronary artery dissection (SCAD) was underdiagnosed and poorly understood for decades. It is increasingly recognized as an important cause of myocardial infarction (MI) in women. We aimed to assess the natural history of SCAD, which has not been adequately explored.

In our large prospectively followed SCAD cohort, long-term cardiovascular events were common. Hypertension increased the risk of recurrent SCAD, whereas beta-blocker therapy appeared to be protective.

Background-Nonatherosclerotic spontaneous coronary artery dissection (NA-SCAD) is underdiagnosed and an important cause of myocardial infarction in young women. The frequency of predisposing and precipitating conditions and cardiovascular outcomes remains poorly described. Methods and Results-Patients with NA-SCAD prospectively evaluated (retrospectively or prospectively identified) at Vancouver General Hospital were included. Angiographic SCAD diagnosis was confirmed by 2 experienced interventional cardiologists and categorized as type 1 (multiple lumen), 2 (diffuse stenosis), or 3 (mimic atherosclerosis). Fibromuscular dysplasia screening of renal, iliac, and cerebrovascular arteries were performed with angiography or computed tomographic angiography/MR angiography. Baseline, predisposing and precipitating conditions, angiographic, revascularization, inhospital, and long-term events were recorded. We prospectively evaluated 168 patients with NA-SCAD. Average age was 52.1±9.2 years, 92.3% were women (62.3% postmenopausal). All presented with myocardial infarction. ECG showed ST-segment elevation in 26.1%, and 3.6% had ventricular tachycardia/ventricular fibrillation arrest. Fibromuscular dysplasia was diagnosed in 72.0%. Precipitating emotional or physical stress was reported in 56.5%. Majority had type 2 angiographic SCAD (67.0%), only 29.1% had type 1, and 3.9% had type 3. The majority (134/168) were initially treated conservatively. Overall, 6 of 168 patients had coronary artery bypass surgery and 33 of 168 had percutaneous coronary intervention in-hospital. Of those treated conservatively (n=134), 3 required revascularization for SCAD extension, and all 79 who had repeat angiogram ≥26 days later had spontaneous healing. Two-year major adverse cardiac events were 16.9% (retrospectively identified group) and 10.4% (prospectively identified group). Recurrent SCAD occurred in 13.1%. Conclusions-Majority of patients with NA-SCAD had fibromuscular dysplasia and type 2 angiographic SCAD. Conservative therapy was associated with spontaneous healing. NA-SCAD survivors are at risk for recurrent cardiovascular events, including recurrent SCAD. (Circ Cardiovasc Interv. 2014;7:645-655.)

No abstract

Intracoronary imaging confirms that SCAD may appear angiographically without multiple radiolucent lumen. Angiographers should be familiar with angiographic SCAD variants to improve SCAD diagnosis, and utilize intracoronary imaging when the diagnosis is uncertain.

Nonatherosclerotic SCAD predominantly affects women, and most have concomitant FMD. We suspect these patients have underlying coronary FMD that predisposed them to SCAD, but this requires proof from histology or intracoronary imaging of the affected coronary arteries.

Spontaneous coronary artery dissection (SCAD) is a non-atherosclerotic cause of myocardial infarction (MI), typically in young women. We undertook a genome-wide association study of SCAD (N cases = 270/N controls = 5,263) and identified and replicated an association of rs12740679 at chromosome 1q21.2 (P discovery+replication = 2.19 × 10 −12 , OR = 1.8) influencing ADAMTSL4 expression. Meta-analysis of discovery and replication samples identified associations with P < 5 × 10 −8 at chromosome 6p24.1 in PHACTR1, chromosome 12q13.3 in LRP1, and in females-only, at chromosome 21q22.11 near LINC00310. A polygenic risk score for SCAD was associated with (1) higher risk of SCAD in individuals with fibromuscular dysplasia (P = 0.021, OR = 1.82 [95% CI: 1.09-3.02]) and (2) lower risk of atherosclerotic coronary artery disease and MI in the UK Biobank (P = 1.28 × 10 −17 , HR = 0.91 [95% CI :0.89-0.93], for MI) and Million Veteran Program (P = 9.33 × 10 −36 , OR = 0.95 [95% CI: 0.94-0.96], for CAD; P = 3.35 × 10 −6 , OR = 0.96 [95% CI: 0.95-0.98] for MI). Here we report that SCADrelated MI and atherosclerotic MI exist at opposite ends of a genetic risk spectrum, inciting MI with disparate underlying vascular biology.