Unmasking Fibromuscular Dysplasia: When Spontaneous Coronary Artery Dissection Rings a Bell

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Elena Sala, MD; Lorenzo Tua, MD; Alberto Cereda, MD; Gabriele Antonio Franchina, MD; Matteo Carlà, MD; Stefano Lucreziotti, MD
Ospedale San Carlo Borromeo, Milan, Italy

Disclosures: The authors report no conflicts of interest regarding the content herein.

The authors can be contacted via Lorenzo Tua, MD, at lorenzo.tua1@gmail.com.

A 47-year-old woman presented to the emergency department complaining of typical chest pain. She had a history of acute coronary syndrome (ACS) 8 years earlier, with no significant coronary artery disease reported at coronary angiography. At that time, assuming a vasospastic etiology, she was put on non-dihydropyridine calcium channel blockers, continuing to the present visit.

Upon arrival, the electrocardiogram showed sinus rhythm, with mild ST depression in inferior and lateral leads. First measurement of cardiac troponin T was 23 ng/L (negative value <5 ng/L) and it increased to 114 ng/L two hours later. Blood count, renal function, and electrolytes were within limits. She was therefore transferred to the cath lab for early coronary angiography, which revealed tapering of the ostium and proximal segment of the left circumflex artery (LCx) and moderate stenosis of the ostium and proximal segment of the obtuse marginal (OM) branch (Figure 1A). The remaining epicardial coronary vessels were unremarkable. Due to non-univocal interpretation of the lesions of the LCx and OM, it was decided to perform a functional evaluation with instantaneous wave-free ratio (iFR). Short after engagement of the left main coronary artery with the guide catheter, total occlusion at the ostium of the LCx was observed (Figure 1B). Intracoronary nitrates were administered, without any benefit. A guidewire was advanced easily to the distal portion of the OM and, through a microcatheter, the intraluminal position of the wire was confirmed. Given the persistent absence of antegrade flow, low-pressure predilatation with a

1.5 mm semi-compliant balloon was performed, without benefit. Suspecting occlusive dissection of the ostium of the LCx, a support guidewire was placed in the left anterior descending artery (LAD). Intravascular ultrasound (IVUS) confirmed proximal dissection of the LCx, from the ostium of the LCx to the middle segment of the OM, with the IVUS probe within the false lumen but the guidewire correctly in the true lumen distally (Figure 2). Meanwhile, after the guidewire had been in place for some time, spontaneous dissection of proximal and mid-segment of the LAD occurred (Figure 1C). At that point, the patient started complaining of worsening angina and hemodynamics began to deteriorate. Given the worsening scenario, an intra-aortic balloon pump (IABP) was positioned. With adequate circulatory support, IVUS-guided percutaneous coronary intervention (PCI) of the LM and LCx-OM bifurcations axes were performed with a culotte technique and the use of four drug-eluting stents (DES) in total. The result was satisfactory, with restoration of distal blood flow and improving vital signs (Figure 1D). The IABP was removed the following day with no complications. 

A few days later, relatives of the patient provided the images of the coronary angiography performed 8 years earlier at a different hospital and whose report concluded as “normal coronary arteries with possible vasospasm”. Surprisingly, what appeared to be a normal, thin OM at the first coronary angiography (Figure 3), presented, before acute dissection occurred, a consistently greater diameter and broader distribution. This allowed for a late diagnosis of spontaneous coronary dissection at the time of the first coronary angiography, which was not diagnosed and progressively healed. 

Given this propensity for spontaneous dissection, it was necessary to consider fibromuscular dysplasia, which is the most common cause of SCAD in young women¹; thus, thoraco-abdominal computed tomography (CT) angiography was performed, showing the typical “string of beads” appearance of the renal arteries and confirming the diagnosis (Figure 4).² Before discharge, invasive coronary angiography was repeated, demonstrating good outcome of the recent stenting procedure and healing of the dissection on the OM. Two-dimensional echocardiography showed preserved ejection fraction, with hypokinesia of the basal inferior and inferolateral segments. The patient was discharged in good general condition, on double antiplatelet therapy, inhibitor of angiotensin-converting enzyme and beta-blocker, proton pump inhibitor, and statin. She was put on a strict clinical, echocardiographic, and angiographic follow-up, and no lesions have developed since. 

Discussion

This case is of particular interest for several reasons: (i) it represents an exemplary case of fibromuscular dysplasia in a young woman, discovered by one of its most serious complications, spontaneous coronary artery dissection (SCAD); (ii) in the literature, a high co-prevalence of extracoronary vascular abnormalities has been described in patients with SCAD, especially fibromuscular dysplasia, and major position papers support arterial imaging from head to pelvis for screening³; (iii) it underlines the challenges in the diagnosis of SCAD, both during the first coronary angiography in 2014, which appeared as a normal, tapering, coronary tree, as well as during the second acute event, when, with the bias of the previous medical report, the first diagnosis was believed to be coronary spasm; (iv) it provides evidence that PCI during ongoing SCAD is feasible if performed with the use of intracoronary imaging. 

References

1. Adlam D, Alfonso F, Maas A, Vrints C; Writing Committee. European Society of Cardiology, acute cardiovascular care association, SCAD study group: a position paper on spontaneous coronary artery dissection. Eur Heart J. 2018 Sep 21;39(36):3353-3368. doi: 10.1093/eurheartj/ehy080
 

2. Persu A, Giavarini A, Touzé E, et al; ESH Working Group Hypertension and the Kidney. European consensus on the diagnosis and management of fibromuscular dysplasia. J Hypertens. 2014 Jul;32(7):1367-78. doi:10.1097/HJH.0000000000000213

3. Hayes SN, Tweet MS, Adlam D, et al. Spontaneous coronary artery dissection: JACC State-of-the-Art Review. J Am Coll Cardiol. 2020 Aug 25;76(8):961-984. doi:10.1016/j.jacc.2020.05.084