Recurrent Spontaneous Coronary Artery Dissection in a Woman With Fibromuscular Dysplasia

Abstract: We report a case of five recurrent myocardial infarctions due to repeat spontaneous coronary artery dissection (SCAD) in a woman with underlying fibromuscular dysplasia. Her angiographic SCADs were missed on two occasions. Patients with a history of SCAD are at risk for recurrent dissections. This case also highlights the angiographic variants of SCAD, and the utility of intracoronary imaging in diagnosing suspected SCAD.

J INVASIVE CARDIOL 2015;27(6):E110-E112

Key words: fibromuscular dysplasia, coronary dissection, cardiac imaging

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It is not infrequent that spontaneous coronary artery dissection (SCAD) is missed in patients presenting with acute coronary syndrome (ACS). SCAD is rare, reportedly accounting for 0.1%-4% of all ACS and 0.1% of sudden cardiac deaths.¹ In our series of young women (age ≤50 years) presenting with myocardial infarction (MI), SCAD accounted for 24% of the events.² SCAD is defined as a non-traumatic separation of the coronary arterial wall by intramural hemorrhage, with or without an intimal tear that creates a false lumen.² Resultant compression of the arterial lumen compromises antegrade blood flow, leading to ischemia or infarction. SCAD typically occurs in patients with an underlying predisposing arteriopathy. We previously reported a strong association between SCAD and fibromuscular dysplasia (FMD).³ In this case report, we describe an unusual presentation of multiple recurrent SCAD in a patient with FMD.

Case Report

A 46-year-old woman first presented in December 2002 with non-ST elevation MI (NSTEMI). Electrocardiogram (ECG) showed dynamic T-wave inversions anteriorly and her troponin I (TnI) was elevated at 6.4 ng/mL. She was a remote smoker, had dyslipidemia, and was obese (body mass index, 40 kg/m²). Coronary angiography was reported to be normal; however, subsequent review revealed a distal to apical left anterior descending SCAD with diffuse 70% stenosis and contrast extravasation in the arterial wall (type 1 SCAD; Figure 1).⁴ Her ejection fraction (EF) was 61%, with apical akinesis. She also had bilateral renal FMD on selective angiography (Figure 1). She was treated conservatively.

The patient was re-admitted 6 months later in June 2003 with atypical chest discomfort. Her ECG showed transient anterior ST elevation and her TnI peaked at 9.9 ng/mL. Repeat angiography showed a new dissection involving the mid to apical LAD, with diffuse 80% stenosis and contrast staining in the arterial wall, and occluded distal LAD (Figure 1). Her EF worsened to 35%, with new inferoapical hypokinesis. The patient was treated conservatively again, as her pain had resolved and she was hemodynamically stable. She was discharged on aspirin, clopidogrel, atorvastatin, ramipril, and verapamil (she had beta-blocker intolerance).  

The patient was readmitted in March 2006 with another NSTEMI, with TnI elevation to 6.4 ng/mL. After stabilization, she underwent exercise treadmill testing but developed pain and further TnI elevation to 22.0 ng/mL. Angiography showed new occlusion of the mid-LAD with contrast staining of the arterial wall. An attempt at wiring the occlusion was unsuccessful. Her previously occluded distal LAD had spontaneously recanalized (Figure 2). Her EF and wall-motion abnormality was unchanged. Warfarin was initiated for 6 months. Screening magnetic resonance angiogram documented vertebral and right internal carotid artery FMD.

She had another recurrence in 2009 (TnI, 3.6 ng/mL) and was treated conservatively after a nuclear scan showed distal anterior wall infarct but no ischemia. Three months later, an elective angiogram showed recanalized distal LAD with Thrombolysis in Myocardial Infarction (TIMI)-3 flow, but there was residual angiographic dissection in her mid-LAD where prior wiring was attempted (Figure 2). 

In April 2013, the patient presented a fifth time with NSTEMI (TnI, 4.0 ng/mL). Her angiogram showed diffuse, minor, smooth stenosis of the distal circumflex, which was initially misdiagnosed as atherosclerosis (Figure 2). However, upon detailed review, the appearance was consistent with type-2 SCAD, which was confirmed on optical coherence tomography (OCT) 2 days later, showing intramural hematoma (Figure 2). Given the spontaneous resolution of her symptoms, the patient was treated conservatively.

Discussion

Patients with SCAD are at risk for recurrent events, with varied reported recurrence rates ranging from 10%-30%.² Most recurrent dissections occur in a different coronary segment from the index event.² In our SCAD series, most patients with recurrent SCAD had only a single recurrence to date.³ The case described here is unusual, with five separate events, four of which were angiographically-proven SCAD. We identified FMD as the only predisposing factor.

Previously, most non-atherosclerotic SCAD was considered idiopathic; however, we recently showed that a large proportion of patients have underlying FMD if properly screened.³ Our patient had FMD in the renal, vertebral, and internal carotid arteries. FMD weakens the affected arterial walls and can predispose to dissection and aneurysm formation.³ In SCAD patients, precipitating factors such as intense exercise or emotional stress can contribute to acute dissections in addition to the underlying arteriopathy.² However, none were identified for this patient’s presentations. We suspect that the dominant risk factor was subangiographic coronary FMD. The diagnosis of coronary FMD is challenging and often only possible post mortem, although intracoronary imaging may be helpful.⁵

To facilitate angiographic diagnosis, a simple classification scheme and algorithm outlining three distinct types of SCAD has previously been described.⁴ Type-1 SCAD, in which there is clear contrast dye staining of the arterial wall with multiple radiolucent lumen, is considered first. If the diagnosis is not made, type-2 SCAD is possible, and is defined by diffuse stenosis of varying severity (commonly involving the mid to distal coronary segments) and made more likely if intracoronary nitroglycerin is given to rule out vasospasm. Lastly, type-3 SCAD, which mimics atherosclerotic disease, is considered.⁴ In type-2 and type-3 SCAD, the angiographic appearance may be difficult to differentiate from atherosclerotic disease or may be missed entirely, especially if the stenosis is diffuse and subtle, without the pathognomonic features seen in type-1 SCAD. Intramural hematoma, even in the presence of intimal disruption, can still mimic atherosclerotic stenosis with the appearance of only luminal compression. Therefore, adjunctive intracoronary imaging, such as optical coherence tomography and intravascular ultrasound, may aid diagnosis and are recommended for confirming type-2 or type-3 SCAD.⁵ 

Conclusion

We describe a unique case of multiple recurrent SCAD in a patient with underlying FMD. This case also highlights the importance of recognizing angiographic variants of SCAD and utilizing intracoronary imaging for uncertain cases when SCAD is suspected. 

References

1. Mortensen KH, Thuesen L, Kristensen IB, Christiansen EH. Spontaneous coronary artery dissection: a Western Denmark Heart Registry study. Catheter Cardiovasc Interv. 2009;74:710-717.
2. Saw J. Spontaneous coronary artery dissection. Can J Cardiol. 2013;29:1027-1033.
3. Saw J, Ricci D, Starovoytov A, Fox R, Buller CE. Spontaneous coronary artery dissection: prevalence of predisposing conditions including fibromuscular dysplasia in a tertiary center cohort. JACC Cardiovasc Interv. 2013;6:44-52.
4. Saw J. Coronary angiogram classification of spontaneous coronary artery dissection. Catheter Cardiovasc Interv. 2014;84:1115-1122. Epub 2013 Dec 4.
5. Saw J, Poulter R, Fung A. Intracoronary imaging of coronary fibromuscular dysplasia with OCT and IVUS. Catheter Cardiovasc Interv. 2013;82:E879-E883.

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From the University of British Columbia, Vancouver, British Columbia, Canada.

Disclosure: The authors have completed and returned the ICMJE Form for Disclosure of Potential Conflicts of Interest. The authors report no conflicts of interest regarding the content herein.

Manuscript submitted August 28 2014, and accepted September 22, 2014.

Address for correspondence: Jacqueline Saw, MD, FRCPC, FACC, University of British Columbia, Clinical Associate Professor, 2775 Laurel Street, Level 9, Vancouver General Hospital Vancouver, BC, V5Z1M9, Canada. Email: jsaw@mail.ubc.ca