Spontaneous coronary artery dissection: new insights from the tip of the iceberg?

S pontaneous coronary artery dissection (SCAD) is a rare clinical entity of unknown cause that typically affects young women without coronary risk factors. 1–5 Initial reports were scarce and based on autopsy findings after episodes of sudden cardiac death, suggesting that the condition had a dismal prognosis. 1,2 An intimal tear was seldom found in autopsy series and, therefore, primary disruption with bleeding of vasa vasorum and intramedial hemorrhage was proposed as the underlying mechanism. 1,2 Alternatively, an intimal tear may lead to separation of coronary wall layers and, eventually, to a double lumen. Pressure-driven expansion of the false lumen induces axial propagation of the disease and true lumen compression, resulting in myocardial ischemia. 2– 4 In some patients, weakening of the arterial wall (hormonal changes, cystic medial necrosis, proteolytic enzymes from periadventitial eosinophils) 2 may provide an underlying vulnerable coronary wall. Coronary angiography is widely used in the diagnosis of SCAD and the classical intimal flap represents the hallmark of this disease. Most patients present with an acute coronary syndrome but have a favorable prognosis. 2–5 However, available evidence on this condition is limited to multiple case reports and small retrospective case series with short follow-up. 1–5 Therefore , 8 decades after its first pathological description, 1 the diagnosis and management of SCAD remains elusive. Tweet et al 6 present the characteristics, management, and outcome of a uniquely large cohort of patients with SCAD seen at the Mayo Clinic during the last 3 decades. Eighty-seven consecutive patients with SCAD were included. In all cases a dissection plane was visible on angiography, but associated atherosclerosis was absent. Mean age was 43 years, and 82% were female. Predisposing conditions included extreme exertion (44% of males) and postpartum status (18% of females). Half of the patients presented with ST-segment elevation myocardial infarction and 14% with life-threatening ventricular arrhythmias. Two thirds of patients underwent revascularization during hospitalization, but acute results of coronary interventions and long-term results of surgery were relatively poor. The estimated 10-year mortality was 7.7%, but the rate of major adverse events was 47%. Interestingly, mortality was lower but the event rate was similar to that seen in a large, carefully matched patient population with atherosclerotic coronary artery disease and acute coronary syndromes. Moreover, at 4 years SCAD recurred in 15 patients (all female). Last but not least, fibromuscular dysplasia (FMD) was incidentally found in 50% of patients with available femoral …