Chest Pain and an Angiographic Abnormality FREE

A 55-year-old man is admitted from the emergency department with1 month of progressively worsening dyspnea and exertional angina. His medical history is significant for hypertension, hyperlipidemia, and gastroesophageal reflux disease. He denies tobacco use, heavy alcohol consumption, illicit drug use, or blunt trauma to the chest. He takes celecoxib for knee pain and swelling. His family history reveals that his mother died of complications of scleroderma. Acute coronary syndrome is ruled out with serial measurement of cardiac biomarker levels and serial electrocardiograms. An electrocardiogram reveals Q waves and poor R-wave progression in the anterior leads and T-wave flattening in the inferior leads. Transthoracic echocardiography reveals an ejection fraction of 45%, left ventricular hypertrophy, mild hypokinesis of the left ventricle, and akinesis of the apical septal segment. The exertional angina resolves over the next day, and the patient remains hemodynamically stable. Results of coronary angiography are shown in the Figure.

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Ischemic cardiomyopathy secondary to spontaneous coronary artery dissection

B. Optimize medical management of ischemic cardiomyopathy

The key clinical feature in this case is recognizing that spontaneous coronary artery dissection (SCAD) is an uncommon but important cause of acute coronary syndrome. The extent of the ischemia, location of the dissection, and the patient's hemodynamic stability ultimately dictate the need for intervention. Although some connective tissue disorders such as Ehlers-Danlos syndrome, Marfan syndrome, and fibromuscular dysplasia are established etiologies of SCAD, scleroderma has not been associated with this condition.

Spontaneous coronary artery dissection is a rare phenomenon, accounting for approximately 0.2% to 0.3% of cases of acute coronary syndromes in the general population. Reported cases have been typically associated with the peri-partum period in young women, intense exercise, blunt chest trauma, cocaine use, connective tissue diseases such as Ehlers-Danlos syndrome or Marfan syndrome, fibromuscular dysplasia, use of oral contraceptives or other medications such as cyclosporine, and a history of atherosclerosis.^1- 3 The exact underlying mechanism leading to SCAD has not been completely elucidated.

Spontaneous coronary artery dissection encompasses a broad spectrum of clinical presentations, ranging from asymptomatic to both stable and unstable angina, acute myocardial infarction, arrhythmias, and sudden cardiac death. The majority of patients present with chest pain, and many patients have ST-segment elevation on electrocardiogram. The diagnosis is typically confirmed by coronary angiography or cardiac computed tomography. Approximately half of the lesions involve the left anterior descending (LAD) artery.⁴ The use of intravascular ultrasound and optical coherence tomography can reveal detailed morphological information on coronary lesions. Unlike coronary angiography alone, these alternative imaging techniques may help to distinguish between atherosclerotic plaques, coronary stenosis, intramural tears or hematomas, cystic media necrosis, and eosinophilic infiltration of the adventitia.⁵ In addition, these imaging modalities can help guide potential percutaneous coronary intervention procedures.⁶

Some studies have shown that up to 60% of lesions managed medically without percutaneous or surgical intervention persist or worsen on repeat angiography and suggest that this kind of initial conservative strategy may delay appropriate treatment.⁷ However, other reports have noted that recurrent dissections are generally rare. The extent of the ischemia, amount of preserved coronary flow, and location of the dissection should dictate the treatment regimen. In patients without ongoing ischemia or hemodynamic instability, medical management alone is usually sufficient. Medical management of SCAD is similar to that for acute coronary syndrome, and acute therapy involves the use of heparin and glycoprotein IIb/IIIa inhibitors, whereas long-term therapy includes use of aspirin, clopidogrel, β-blockers, nitrates, and statins. Typically, patients with lesions involving multiple vessels or the left main artery are treated with coronary artery bypass graft surgery; proximal lesions of the LAD, circumflex artery, and right coronary arteries are treated with percutaneous coronary intervention; and distal lesions of the LAD are treated conservatively without intervention.^8- 10

In this patient, an electrocardiogram obtained at admission was notable for Q waves and poor R-wave progression in the anterior leads and for Q waves and T-wave flattening in the inferior leads, consistent with prior anterior- and inferior-wall infarctions.

Coronary angiography showed dissection of the mid- to distal left anterior descending coronary artery with TIMI (Thrombolysis in Myocardial Infarction) grade 3 flow distal to the dissection, suggesting a well-healed mid-distal LAD dissection with preservation of the remaining coronary vasculature. A coronary artery dissection results in separation of the layers of the arterial wall, creating a false lumen such as that seen on the angiogram in this instance. Disruption of flow distal to the lesion would be suggestive of occlusion of the vessel by the dissection, which would require mechanical intervention to restore flow.

Because this patient's dissection was not acute, was located in the mid-distal LAD, and had preserved coronary blood flow, treatment consisted of optimizing medical management of this patient's newly diagnosed ischemic cardiomyopathy. Although the exact etiology of SCAD in this instance remained unclear, a possible mechanism may have involved an initial rupture of atherosclerotic plaque, which in turn led to the development of a subintimal dissection. Also, use of celecoxib has been reported in a small number of cases to be associated with coronary artery dissection, although no studies to date have explored this association.