Successful management of subacute stent mal-apposition confirmed using optical coherence tomography following cardiac arrest due to spontaneous coronary artery dissection in a middle-aged woman: a case report

Abstract

Background

In patients with spontaneous coronary artery dissection (SCAD), percutaneous coronary intervention is considered only in a limited number of situations. There are a few reports on therapeutic interventions for SCAD in the acute phase, none on those performed during the subacute phase.

Case summary

A previously healthy 51-year-old woman was transported to our hospital, where ST elevation was noted on an electrocardiogram in the emergency room. Subsequently, she experienced ventricular fibrillation and cardiac arrest. Extracorporeal membrane oxygenation was initiated; coronary angiography (CAG) revealed severe right coronary artery stenosis. Intramural haematoma on intravascular ultrasonography led to SCAD diagnosis. Despite continued electrical defibrillation after extracorporeal membrane oxygenation initiation, the ventricular fibrillation persisted. However, after relieving ischaemia in the right coronary artery territory via stent placement, the ventricular fibrillation ceased. She developed a cerebral haemorrhage; from days 8 to 36, dual antiplatelet therapy (DAPT) had to be completely discontinued. On hospital day 56, although CAG detected no significant stenosis, optical coherence tomography (OCT) revealed marked stent mal-apposition. Additional dilation was performed using a non-compliant balloon. On follow-up OCT on day 196, most of the struts were covered by the intima. She received DAPT for 1 year, then switched to single antiplatelet therapy and remained free of cardiovascular events for 3 years.

Discussion

Although no recommended treatments for mal-apposition following stenting for SCAD currently exist, dilation in the subacute phase may lead to a favourable outcome. This approach warrants consideration as a future therapeutic option for SCAD.

Learning Points.

• Spontaneous coronary artery dissection is usually managed conservatively; however, revascularization, including stenting, may be required when ongoing ischaemia persists.

• Late-acquired stent mal-apposition can occur after stenting for spontaneous coronary artery dissection, probably because of resorption of the intramural haematoma.

• In patients with systemic complications, delayed balloon dilatation for subacute stent mal-apposition after spontaneous coronary artery dissection may result in favourable vascular healing.

Introduction

Spontaneous coronary artery dissection (SCAD) is the disruption of the coronary arterial wall that can cause acute myocardial infarction, particularly in young women.^1–3 Although percutaneous coronary intervention (PCI) for SCAD remains controversial, it may be considered for ongoing ischaemia or haemodynamic instability.⁴ Stenting can lead to late-acquired mal-apposition during haematoma resorption⁵; however, no established treatment exists. We describe a middle-aged woman with SCAD-related cardiac arrest who developed subacute stent mal-apposition, successfully treated with balloon dilatation.

Summary figure

Case presentation

A previously healthy 51-year-old woman was admitted with hyperventilation and headache after an argument with her son. She had never smoked, and her family history was unremarkable. On arrival, she reported chest pain: blood pressure, 108/60 mmHg; pulse rate, 54 beats/min; respiratory rate, 20 breaths/min; and oxygen saturation, 100% on room air. Electrocardiography showed ST elevation in the inferior leads, and transthoracic echocardiography revealed inferior wall hypokinesis. She was diagnosed with ST-segment elevation myocardial infarction. During transfer to the catheterization laboratory, ventricular fibrillation (VF) developed and progressed to cardiac arrest. Despite amiodarone and repeated defibrillation, extracorporeal cardiopulmonary resuscitation with extracorporeal membrane oxygenation (ECMO) was required. Coronary angiography (CAG) performed via the left femoral artery showed severe proximal right coronary artery (RCA) stenosis. Intravascular ultrasound (IVUS) (AltaView, Terumo, Tokyo, Japan) revealed an intramural haematoma, confirming SCAD. IVUS was used because optical coherence tomography (OCT) requires flushing, which may increase the intraluminal pressure and extend the dissection or haematoma.^6,7 Fenestration using a 3.0-mm Wolverine cutting balloon (Boston Scientific, Marlborough, MA, USA) failed and caused distal extension of the intramural haematoma. Because VF persisted despite defibrillation under ECMO, two sirolimus-eluting stents (Ultimaster Nagomi 3.0×50 mm and 3.0×28 mm; Terumo, Tokyo, Japan) were deployed from the distal to proximal RCA, resulting in VF cessation (Figure 1). After PCI, intra-aortic balloon pumping (IABP) was inserted via the left femoral artery.

Figure 1.

Initial and post-stenting coronary angiography (CAG), intravascular ultrasound (IVUS). Severe stenosis was observed in the proximal-mid portion of right coronary artery (A), which is a type 2A spontaneous coronary artery dissection. IVUS revealed an intramural haematoma (indicated by * in F–H). Fenestration was unsuccessful. Stenting was necessary using Ultimaster Nagomi 3.0×50 mm and 3.0×28 mm (B–C). Subsequent CAG showed good flow (D), and IVUS demonstrated that the stent compressed the haematoma (indicated by † in K–M).

She was admitted to the intensive care unit, where targeted temperature management at 36°C was continued until day 3. On day 2, abdominal distention and severe anaemia developed; haemoglobin decreased from 14 to 7.5 g/dL, necessitating 12 units of red blood cells. Contrast-enhanced computed tomography (CT) showed a left retroperitoneal haematoma without angiographic extravasation, which stabilized following removal of the IABP and conservative management. ECMO was discontinued on day 3, and renal replacement therapy (RRT) was initiated on day 4 for persistent renal dysfunction. On day 8, slurred speech occurred; CT revealed cerebellar and lobar haemorrhage with obstructive hydrocephalus, requiring ventricular drainage (see Supplementary material online, Figure  S1). Therefore, dual antiplatelet therapy (DAPT) was reluctantly stopped.

She gradually improved with rehabilitation. RRT was discontinued, and DAPT was resumed on day 36 after confirming the absence of complications with head CT and laboratory testing. On day 56, OCT (Dragonfly Opstar imaging catheter, Abbott, North Chicago, IL, USA) and angioscopy (Forward-looking, Project OVALIS, Osaka, Japan) revealed marked stent mal-apposition with thrombus between the visible struts (Figure 2). Despite 2 months passing since stenting, the mal-apposition was significant; therefore, dilatation with a 3.25-mm Hiryu Plus balloon (Terumo, Tokyo, Japan), a non-compliant balloon, was performed. Subsequent OCT confirmed resolution (Figure 2). She was discharged on day 60. On day 196, follow-up CAG and OCT confirmed partial neointimal coverage of the previously mal-apposed segment, although some struts remained mal-apposed (Figure 3). DAPT was continued for 1 year, then switched to single antiplatelet therapy. No autoimmune disease or fibromuscular dysplasia was identified. She remains event-free 3 years after onset.

Figure 2.

Angioscopy and optical coherence tomography (OCT) in the subacute phase. Coronary angiography revealed no significant stenosis (A). Based on OCT, nearly all stent struts exhibited a gap of 200 μm or more from the arterial wall, demonstrating marked mal-apposition. This was especially pronounced distally(B–F). Most stent struts are fully visible, similar to immediately after implantation (NIC grade 0), the intima between stent segments appears white to light yellow (yellow grade 0–1), thrombus extended between struts (thrombus grade 2) (c-1, d-1). Angioscopy was superior to OCT for thrombus visualization. Ballooning was performed using a Hiryu plus 3.25 mm. Subsequent OCT confirmed proper apposition (b-2 – f-2). X-1 indicates the angioscopy image of X, and X-2 indicates the OCT image of X after ballooning.

Figure 3.

Coronary angiography and optical coherence tomography in the remote phase. No significant stenosis was observed (A). The proximal 10 mm of the proximal stent showed mal-apposition with relatively poor coverage, but the remainder demonstrated adequate coverage with a neointima exhibiting a homogeneous low signal pattern. (B–F).

Discussion

In this case, adequate stent apposition was achieved in the acute phase, whereas marked stent mal-apposition was observed in the subacute phase (see Supplementary material online, Figure S2). This was considered to be caused by resorption of the intramural haematoma after the acute phase. Currently, no established treatment strategy exists for late stent mal-apposition in SCAD. However, if the degree of mal-apposition is excessively severe, the stent struts do not become endothelialized, raising the need to consider lifelong DAPT. Several cases of mal-apposition after SCAD have been reported.^5,7,8 Mal-apposition has also been reported to improve naturally with conservative treatment alone.⁵ Only one case has been reported wherein mal-apposition was identified and treated with ballooning 11 days after stenting for SCAD, with complete coverage confirmed 30 months after the procedure.⁵ The extent to which mal-apposition would improve naturally also remains unclear.

In our case, the acute phase was marked by general instability and complications, including cerebral haemorrhage. This bleeding complication was considered mainly related to coagulation abnormalities associated with postcardiac arrest syndrome and ECMO support. However, the possible contribution of occult fibromuscular dysplasia to intracerebral haemorrhage could not be completely excluded.⁹ This case suggests that even after some time has elapsed since stenting for SCAD, ballooning can still achieve endothelialization. The Ultimaster Nagomi used in this case is said to release drugs for 3–4 months; therefore, we considered that within this period, inhibition of neointimal proliferation would still be possible. Follow-up OCT revealed areas with incomplete coverage; however, most struts were covered by neointima. Therefore, DAPT was continued for another year.

Considering her age and history of intracerebral haemorrhage, avoiding indefinite DAPT by correcting severe mal-apposition was considered preferable, and this approach was ultimately successful. Although PCI for SCAD-related stent mal-apposition cannot be routinely recommended, appropriate correction with balloon angioplasty may facilitate endothelialization and represent a potential option for preventing very late stent thrombosis. To the best of our knowledge, this is the first report to visualize marked post-SCAD stent mal-apposition by angioscopy.

One limitation of this case is that coronary artery evaluation was not performed after day 196. However, as the patient remained event-free, this was considered acceptable.

Conclusion

After PCI for mal-apposition in the subacute phase of SCAD, subsequent endothelialization was confirmed. Subacute-phase PCI might be considered a therapeutic option for future SCAD cases.

Lead author biography

After graduating from Kyoto Prefectural University of Medicine, he completed his initial residency at Nagoya Tokushukai General Hospital. Since then, he has continued to work as a cardiologist. His specialties include coronary intervention, structural heart disease treatment, catheter ablation, and device therapy.

Supplementary material

Supplementary material is available at European Heart Journal – Case Reports online.

Author contributions

Takeshi Mori (Conceptualization, Data curation, Visualization, Writing—original draft, Writing—review & editing [lead]), Hidekazu Aoyama (Conceptualization [equal], Methodology, Resources [lead], Writing—original draft, Writing—review & editing [supporting]), Miyuki Ando (Writing—review & editing [supporting]), Akimitsu Tanaka (Supervision [lead], Writing—review & editing [supporting]), and Kazuo Kato (Supervision, Writing—review & editing [supporting])

Consent: The authors confirm that written consent for the submission and publication of this case report, including the image(s) and associated text, was obtained from the patient in line with COPE guidance.

Funding

This work was not supported by any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Data availability

The data underlying this article will be shared on reasonable request to the corresponding author.