ORIGINAL REPORT

Successful Surgical Treatment of Spontaneous Coronary Artery Dissection Joshua E. Lane, MD, Richard G. Cartledge, MD, and Joseph H. Johnson, MD The Department of Surgery, Mercer University School of Medicine, The Medical Center of Central Georgia, Macon, Georgia To present a case of spontaneous coronary artery dissection (SCAD). Spontaneous coronary artery dissection is rare and often difficult to surgically repair. Additionally, diagnosis by coronary angiography is uncommon. We present a case of SCAD in a postpartum woman who underwent successful surgical correction of the left anterior descending artery. Such surgical intervention in cases similar to ours is critical for survival. (Curr Surg 58:316-318. © 2001 by the Association of Program Directors in Surgery.) KEY WORDS: coronary artery dissection, postpartum, surgi-

cal treatment

INTRODUCTION Spontaneous coronary artery dissection (SCAD) is a rare cause of myocardial infarction. It occurs in younger populations and has a predilection for women.1-3 Three major groups have been associated with SCAD: patients with atherosclerotic coronary artery disease, women in the postpartum period, and idiopathic causes.2 Coronary artery dissection is often fatal, with approximately 75% of cases diagnosed at autopsy.2,4 The origin, pathogenesis, diagnosis, and treatment remain unclear. Both medical and surgical treatments exist; however, coronary artery bypass grafting has been commonly recommended.2 We present the case of SCAD in a postpartum woman with chest pain who underwent successful coronary artery bypass surgery.

CASE REPORT A 37-year-old Caucasian woman presented to the emergency room with sudden onset of chest pain. She had no prior history of cardiovascular disease, trauma, or collagen tissue disease. Surgical history was pertinent for laparoscopic removal of an ovarian cyst and an abortion. At the time of presentation, the patient was 4 days postpartum from the delivery of her second child. She smoked 1 pack of cigarettes per day and drank alcohol

Correspondence: Inquiries to Joshua E. Lane, MD, The Medical Center of Central Georgia, 777 Hemlock St., Hospital Box 162, Macon, GA 31208; fax: (801) 340-1519; e-mail: [email protected].

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minimally. She was taking no medications and was not on oral contraceptives. The patient had no drug allergies. Additionally, no history of coronary artery disease existed within her family. Vital signs included the following: blood pressure, 122/64 mm Hg; pulse, 80 beats/minute; respirations, 19 breaths/minute; weight, 126 lbs. She was a well-developed and well-nourished Caucasian woman. Physical examination was normal. Electrocardiogram was indicative of an acute anterior myocardial infarction. Initial cardiac enzyme studies included the following: total CPK 164 U/l, CK-MB 5.7 ng/ml, troponin-T 0.01 ng/ml, relative index 3.5, and serum myoglobin 126 ng/ ml. The patient was treated with intravenous aspirin and nitroglycerin in the emergency room. She was not a candidate for thrombolytic therapy because of her recent delivery. She was urgently transported for cardiac catheterization, which showed evidence of dissection of the left anterior descending (LAD) artery with involvement of the circumflex artery (Fig. 1). Angioplasty was attempted but was not successful. At this point, she had multiple episodes of ventricular tachycardia and fibrillation, which were treated with cardioversion and intravenous lidocaine. Coronary stenting did not maintain vessel patency. She was emergently transported to the operating room, and at which time, she again went into ventricular fibrillation. She underwent bypass grafting to the LAD artery as a single graft and to the circumflex and diagonal arteries as sequential grafts. She had no postoperative complications and was discharged on the fifth postoperative day. On follow-up examination, she was without complications, with normal exercise tolerance at 6 months postoperatively.

DISCUSSION Spontaneous coronary artery dissection is a rare cause of myocardial infarction and is often fatal. Approximately 50% of patients with coronary artery dissection die abruptly and 18% to 20% die within hours.4 Spontaneous dissection of the coronary vasculature is less likely to occur than is secondary to blunt trauma, associated with aortic dissection, associated with collagen vascular disorders such as Marfan’s syndrome, sarcoidosis, angiitis, previous renal transplantation, or iatrogenic cases.1,4

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FIGURE 1. Coronary angiography (left anterior oblique with cranial angulation) demonstrates dissection of the left anterior descending artery (arrow).

Most patients have died secondary to dissection, with only a few survivors.2,4 Spontaneous coronary artery dissection has been typically associated with patients in the postpartum period, with atherosclerotic coronary artery disease, and undetermined causes.2 Interestingly, an association with hypertension does not appear to exist.1 The LAD artery is most commonly affected, followed by the right coronary artery.1,4,5 Dissection of the LAD artery or the main coronary artery is the most serious of coronary artery dissections.4 The pathogenesis of SCAD has not yet been elucidated. Although SCAD has been reported in men, such reports are uncommon.6-8 Furthermore, a predilection appears to exist for postpartum women. The occurrence of SCAD in pregnant and postpartum women may be suggestive of the underlying pathogenesis. Although the origin is unknown, microstructural changes in the vasculature secondary to hormonal and hemodynamic factors are likely involved.9,10 Weakening of the tunica media of coronary vessels during pregnancy has been suggested to be a pathogenic origin of SCAD in these patients.4 Such weakening during pregnancy may be secondary to loss of reticular fiber corrugation, smooth muscle hypertrophy, media mucopolysaccharide alterations, and shear stress.1 This vascular degeneration and weakening combined with the stress of labor and delivery may predispose to or actually initiate an intimal tear, with subsequent hemorrhage into the tunica media. The presence of eosinophilic infiltrates in the adventitia of involved coronary arteries has been reported in necropsy cases.11 A lytic action of an eosinophil-derived protease is yet another hypothesis to explain the origin of SCAD.12 CURRENT SURGERY • Volume 58/Number 3 • May/June 2001

Diagnosis is made by coronary angiography; however, this is rare.4 Treatment options include medical therapy, coronary artery bypass grafting, and interventional procedures. Surgical intervention has proven successful in several studies.1,3 Spontaneous coronary artery dissection should be considered within the differential diagnosis of a young patient, especially a postpartum woman, presenting with acute ischemic symptoms.

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