Complete healing of spontaneous coronary artery dissection extending from the left main trunk to the left anterior descending and the left circumflex artery

Abstract

Spontaneous coronary artery dissection (SCAD) is defined as a spontaneous separation of the coronary artery wall that is not iatrogenic or related to trauma and usually affects young women. We describe a 65-year-old woman who presented with SCAD extending from the left main trunk involving the left anterior descending artery and the left circumflex artery, and coronary artery bypass graft surgery was performed to treat the dissection. Coronary angiography performed 3 months later, showed complete angiographic healing. A conservative management strategy is known to be associated with spontaneous angiographic healing in patients with SCAD who are hemodynamically stable. Healthcare providers should consider SCAD among the differential diagnoses in patients presenting with acute coronary syndrome, particularly in women. Further studies are needed to establish an optimal management strategy for SCAD.

<Learning objective: Spontaneous coronary artery dissection (SCAD) might be a cause of acute coronary syndrome not only in younger but also in older women. Even if the area of the dissection is broad, healing can be expected in future. Therefore, it is important to select between conservative and invasive therapy such as percutaneous coronary intervention or coronary artery bypass graft including selection of graft, i.e. saphenous vein graft and radial arteries, and internal mammalian arteries.>

Introduction

Spontaneous coronary artery dissection (SCAD), which was previously considered a rare disease entity that was commonly associated with pregnancy [1] has been reported as an infrequent cause of acute coronary syndrome (ACS) (0.1–0.4%) [2]. Recent estimates report a SCAD prevalence of 1.7–4% in patients presenting with ACS on the basis of a modern series [3]. Although SCAD was considered to affect young women, 58% of patients were observed to be >50 years of age, 62% of affected women were observed to be post-menopausal, and the oldest patient was observed to be 84 years of age in the Vancouver cohort study that investigated 168 patients [4], suggesting that SCAD may not be a rare cause of ACS, even in elderly women.

We present the case of a patient who demonstrated complete angiographic healing after a coronary artery bypass graft (CABG) procedure for a left main trunk (LMT) dissection involving the left anterior descending (LAD) and the left circumflex artery (LCX).

Case report

We describe a 65-year-old woman without significant cardiovascular risk factors who was transferred to our hospital with sudden onset of chest pain. A physical examination was unremarkable. Laboratory investigations showed that during the acute phase, there was no increase in the level of creatine phosphokinase. Her peak troponin level was noted to be 6 pg/mL (reference range <26 pg/mL). An electrocardiogram (ECG) showed ST depression in leads V2-6. Echocardiography showed normal left ventricular function and no proximal aortic dissection. We suspected ACS, and an emergency coronary angiography (CAG) was performed, which showed a dissection extending from the LMT to the LAD and the LCX (Fig. 1). Because LMT was already extremely stenotic, even 4Fr catheter almost wedged into LMT. Her vital signs were observed to be stable. CT denied the dissection of proximal aorta (Fig. 2A). We decided to perform a CABG because percutaneous coronary intervention (PCI) for the LMT with involvement of the LAD and LCX was deemed a risky procedure without support of cardiac surgeons, because our hospital had no cardiac surgeon. She was transferred to another hospital which had a department of cardiac surgery. CABG was performed so that LAD and LCX were bypassed with each left internal mammalian artery and saphenous vein graft (SVG). Coronary-computed tomography (C-CT) performed a month later showed no dissection of LMT (Fig. 2B) and a shrunken graft and an almost intact coronary artery (Fig. 2C). CAG performed 3 months later showed complete healing of the dissection, and while 1 graft was noted to be occluded, native flow through the LCX was noted to be superior to that through the other graft (Fig. 3).

Fig. 1.

Coronary angiography (CAG), which was engaged to the true lumen of the left coronary artery showing that the coronary flow is intact through the distal arteries (A). CAG, which was engaged to false lumen showing the blunt end at the branch bifurcation (B).

Fig. 2.

Computed tomography (CT) performed in acute phase showing a dissection of left main trunk (LMT) without dissection of ascending aorta (A). Coronary-CT performed a month later showing no dissection of LMT (B) and a shrunken graft and the remaining stenosis of LMT and almost intact left anterior descending artery and left circumflex artery (C).

Fig. 3.

Coronary angiography (CAG) performed 3 months later showing the left coronary artery with complete healing of the dissection and one of the grafts (left internal thoracic artery) is observed to be occluded, although native flow through the left circumflex artery is observed to be superior to that through the other graft (saphenous vein graft).

C-CT performed 1–1/2 years later showed intact coronary arteries and occlusion of all grafts. CT angiography did not show any evidence of the classic/typical ‘string of beads’ appearance, or focal and/or tubular stenosis to suggest fibromuscular dysplasia (FMD) of other arteries, such as the bilateral renal and/or the iliac arteries.

Discussion

To our knowledge, ours is the first report to describe complete angiographic healing in a patient following LMT dissection involving the LAD and the LCX, which was treated with a CABG procedure.

Although SCAD is defined as a spontaneous separation of the coronary artery wall that is not iatrogenic or related to trauma and usually affects young women [1], [5], the pathophysiology, epidemiology, and management of this disease entity remain relatively poorly understood. SCAD is being increasingly recognized as an important cause of ACS—recent reports have indicated an incidence of approximately 4% among patients with ACS who were assessed using optical coherence tomography (OCT) [2]. Reportedly, the incidence is much higher (approximately 25%) in young women aged <50 years presenting with myocardial infarction [4]. SCAD may not be a rare cause of ACS, even in elderly women.

The pathognomonic angiographic appearance of SCAD includes the presence of extraluminal contrast staining, multiple radiolucent lumens, spiral dissection, and intraluminal filling defects [6]. The predominant angiographic feature of SCAD consists of smooth narrowing of varying severity and length secondary to intramural hemorrhage [4]. We diagnosed our patient with SCAD and not an iatrogenic dissection because neither additional chest pain nor new ECG changes were noted during CAG was performed, and we already confirmed the broad area of dissection just after the initial angiography was performed. If this dissection had been iatrogenic, we would observe the progression of dissection during the initial angiography and the patient would have an additional chest pain or new ECG change. Additionally, when we engaged the catheter into left coronary artery and performed a test shot, we already noticed the abnormality of the ostium, but regrettably the image was not recorded. Thus, we excluded iatrogenic dissection. Furthermore, we excluded the possibility of a previous proximal aortic dissection using C-CT.

The underlying etiology of SCAD appears to be multifactorial in nature. Usually, an associated underlying predisposing arteriopathy may be present, which may be compounded by a precipitating stressor, culminating in the phenotypic expression of SCAD. The etiology of SCAD is not fully elucidated in both young and elderly. Not only in young but in elderly, atherosclerosis is not thought to be a cause of SCAD. In our patients, there was no atherosclerosis risk and C-CT showed neither plaque nor calcification.

Some papers reported that coronary spasm might be associated with SCAD [7]. Retrospectively, she reported chest discomfort from a few years previously; coronary spasm might be a cause. Several potential predisposing non-atherosclerotic arteriopathies are known to be associated with SCAD, and FMD is frequently cited as the predominant arteriopathy closely associated with this disease entity. However, examination of other medium-sized arteries including the renal, iliac, and cervical arteries did not reveal any indication of FMD in our patient. Although any coronary artery can be affected by SCAD, the LAD is observed to be the most commonly involved vessel (34–42%) [5], [8]. Overall, the LAD and its branches (diagonal or septal) are affected in 45–61%, the LCX and branches in 15–45%, the right coronary artery and its branches in 10–39%, and the left main in 0–4% of patients [3], [8].

Based on expert opinion derived from observational data, an overall conservative treatment approach is the preferred management strategy in these patients [1]. This recommendation is based on the common observations that in most cases, arteries demonstrating SCAD heal spontaneously, and that revascularization is associated with high failure rates [1]. Therefore, a conservative approach is typically recommended because spontaneous angiographic healing occurs in most cases except in patients presenting with ongoing ischemia, recurrent chest pain, hemodynamic instability, or LMT dissection. In our patient with LMT dissection, we had to select whether to perform PCI or CABG. The selection to proceed with PCI or CABG differs widely among clinicians and depends on the acute presentation [1]. PCI using cutting balloon may be one of the attractive strategies, because making re-entry of dissection is rational and non-invasive compared to CABG. The initial angiography showed that the distal flow of LAD seemed intact, but LMT was very stenotic and we thought that it was difficult to safely engage 6 Fr guiding catheter into LMT without enlargement of false lumen. Additionally, our hospital had no cardiac surgeon. In our patient, we opted to perform a CABG because a PCI without a backup of cardiac surgeons was deemed a risky procedure.

However, a small study series has shown that long-term results with CABG appear suboptimal, with reported graft patency of 27% [9], which may be related to spontaneous arterial healing, with subsequent competitive flow causing graft thrombosis. In our patient, it can be reasoned that the retrograde flow from the graft to the native artery might have contributed to the healing mechanism. We did not expect such complete healing of dissection and occlusion of all grafts in acute phase. We should have selected SVG graft as both grafts to keep internal mammalian arteries for the future when it is necessary.

The optimal management strategy for SCAD remains undetermined because no randomized trials have compared medical therapies versus revascularization strategies, unlike trials/studies that have investigated atherosclerotic disease. A recent study has reported that OCT is an effective modality that can help to distinguish SCAD from other entities and identify it as an etiological factor associated with ACS. OCT-guided PCI for SCAD has shown favorable results, as well as those for other ACS etiologies. OCT-guided PCI could be considered a useful therapeutic option for the management of SCAD [10].

In conclusion, healthcare providers should consider SCAD among the differential diagnoses in patients presenting with ACS, particularly in women, and also be mindful of the fact that long-segment dissection is associated with spontaneous healing. Further studies are warranted to evaluate the optimal management strategy for SCAD.

Conflict of interest

The authors declare no conflict of interest.