A 50-year-old woman had sudden-onset retrosternal chest pain. Paramedics were called, and her electrocardiogram (ECG) showed ST-elevation in the anterior precordial leads with associated Q-waves compatible with acute myocardial infarction (MI) (Figure 1). Forty minutes after the onset of chest pain, she suffered a witnessed ventricular fibrillation cardiac arrest. She received 1 minute of chest compressions and was defibrillated once, with return of spontaneous circulation. She was transferred to the nearest hospital with percutaneous coronary intervention (PCI) capability for urgent coronary angiography.
The patient's medical history included hypertension, smoking, chronic obstructive pulmonary disease, hysterectomy, depression and occasional pulsatile tinnitus. She did not have a history of dyslipidemia or diabetes.
Upon arrival at hospital, the patient had ongoing mild chest pain, with persistent infarct pattern on ECG. Her blood pressure was 113/75 mm Hg, and heart rate was 112 beats/min. Coronary angiography showed smooth-appearing coronary arteries with tortuosity noted in all vessels (Figure 2A). An unusual reduction in vessel calibre was noted in the distal left main artery and proximal left anterior descending artery (LAD) over a 20- to 25-mm segment (Figure 2B and 2C). The interventional cardiologist was concerned about the possibility of spontaneous coronary artery dissection (SCAD) rather than traditional atherosclerosis with plaque rupture. Optical coherence tomography (OCT) confirmed SCAD (Figure 3). These images showed intramural hematoma with both true and false lumens starting from the distal left main artery and extending about 20 mm into the proximal LAD, causing 50%-80% narrowing. Because brisk flow was noted in the coronary artery, and the patient was minimally symptomatic and hemodynamically stable, she was managed conservatively without PCI. Echocardiography showed a left ventricular ejection fraction (LVEF) of 35%-40% with apical akinesis, and no left ventricular thrombus. An exercise stress test was negative for ischemia. The patient's discharge medications were acetylsalicylic acid (ASA), metoprolol, perindopril and inhalers.
The patient returned to hospital 2 weeks later with recurrent intermittent chest pain lasting 5-30 minutes. Her ECG showed precordial T-wave inversions similar to her predischarge ECG, and serum troponin levels were normal. Because of the critical location of the original SCAD, repeat angiography was performed. This examination showed normal coronary arteries, with complete angiographic resolution of the previously noted intramural hematoma and luminal compression of the left main artery and proximal LAD (Figure 2D), and improvement of LVEF to more than 50%.
Over the ensuing months, the patient continued to have intermittent episodes of chest pain and was seen in a regional SCAD clinic. Vascular screening was undertaken with 2 computed tomography angiograms of the head and neck, and the chest, abdomen and pelvis. She received a diagnosis of fibromuscular dysplasia (FMD) of both internal carotid arteries and coronary arteries. She was admitted to hospital again 6 and 8 months after the original presentation for recurrent chest pain, without ECG or cardiac marker evidence of infarction. Echocardiography performed 6 months post-MI showed normal left ventricular size and function (LVEF 62%). Coronary angiography at 8 months showed normal coronary arteries.
Spontaneous coronary artery dissection...