Stent-Assisted Coil Embolization of Coronary Artery Aneurysm

ABSTRACT: Coronary artery aneurysms are uncommon diseases with potential complications including rupture and ischemia from embolic events or thrombosis. No consensus has been established regarding the optimal therapy for coronary artery aneurysms. Percutaneous catheter-based treatments using membrane-covered stents and coil embolization have been described. However, only few reports of stent-assisted coil embolization for coronary artery aneurysms have been published to date. Therefore, we report a case of coronary artery aneurysm successfully treated with stent-assisted coil embolization.

J INVASIVE CARDIOL 2013;25(8):E175-E177

Key words: coronary artery aneurysm

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Coronary artery aneurysms (CAAs) are uncommon diseases. Many are asymptomatic, and found incidentally on coronary angiography. The potential complications include rupture and ischemia from embolic events or thrombosis.¹ No consensus has been established regarding the optimal therapy for CAAs. The use of surgical resection/exclusion, polytetrafluoroethylene (PTFE)-covered stent implantation, and coil embolization of the aneurysm were reported.^2-4 In this report, we describe a case of CAA successfully treated with stent-assisted coil embolization.

Case Report. A 65-year-old woman was admitted to our hospital because of inferior acute myocardial infarction. She underwent emergent coronary angiography, which revealed occlusion of the proximal right coronary artery. The occlusion was successfully recanalized with stent implantation. The coronary angiography also revealed coronary aneurysm with 75% stenosis proximal to the aneurysm in the mid-portion of the left anterior descending artery (Figure 1). The aneurysm was 7.4 x 5.5 mm in size. No symptoms or ischemic findings associated with the stenosis and aneurysm were observed. The patient was managed conservatively.

Five years later, a coronary computed tomographic (CT) angiogram revealed that the aneurysm had grown in size to 8.8 x 5.8 mm. The aneurysm was located distal to a lesion with 75% stenosis and accompanied by a diagonal branch near the neck. The coronary CT angiogram also showed moderate calcification of the lesion (Figure 2). After careful discussion with the patient, we decided to treat the lesion with stenting and to perform stent-assisted coil embolization for the aneurysm. 

The intervention was performed through the right femoral artery using a 7 Fr guide catheter (Mach1 CLS 3.5; Boston Scientific Corporation). The lesion was predilated with a non-compliant balloon (2.5 x 12 mm Voyager NC; Abbott Vascular) at 22 atm. A 23-mm long bare-metal stent (2.5 x 23 mm Multi-Link Mini Vision; Abbott Vascular) was used. Advancing the stent to the desired segment of the artery proved very difficult. Ultimately, the stent was successfully delivered to the lesion using a second buddy wire. The post-stent intravascular ultrasound images showed excellent stent expansion. After stenting, another 0.014˝ wire (Fielder FC; Asahi Intecc) was advanced through the stent struts into the aneurysm. A 45° preshaped microcatheter (Excelsior SL-10; Boston Scientific Corporation) was placed inside the aneurysm over the wire. Five GDC detachable coils (GDC 10-360° Soft SR: 6 mm x 11 cm, 6 mm x 11 cm, 5 mm x 9 cm, and 4 mm x 8 cm; GDC 10-Soft SR 2D: 3 mm x 8 cm; Boston Scientific Corporation) were subsequently deployed inside the aneurysm. To avoid coil migration, a compliant balloon (2.5 x 12 mm Sprinter Legend RX; Medtronic) was inflated in the stent at the orifice of the aneurysm only during coil delivery into the aneurysm. A final angiogram showed minimal residual flow into the aneurysm (Figure 3). The diagonal artery originating from near the ostium of the aneurysm was nearly occluded. The patient was asymptomatic. The postprocedural electrocardiogram remained unchanged. Serial creatine phosphokinase assays did not rise from the normal baseline. The patient was discharged 2 days after undergoing the procedure. One year later, the patient remained asymptomatic. A coronary angiogram showed complete occlusion of the aneurysm and no restenosis in the stent (Figure 4).

Discussion. The natural history of CAA is poorly understood. The potential risks are spontaneous rupture, thrombosis, and distal embolization. However, the exact incidence of these complications is not known. No consensus has been established regarding the optimal therapy for CAAs.¹ The therapy must be individualized according to clinical and anatomical statuses. In this case, the aneurysm had grown bigger than 8 mm in diameter during the 5-year observation period. The coronary angiogram showed slight progression of the stenosis proximal to the aneurysm. Multiple surgical techniques have been described to treat coronary aneurysms.² Percutaneous treatment for coronary aneurysms is less invasive compared with surgical techniques.

PTFE-covered stents were demonstrated to be effective in excluding CAAs.³ However, their bulky nature may result in technical difficulties with delivery in tortuous or calcified coronary artery. Furthermore, they prevent any access to a side branch. In our case, moderate calcifications in the lesion and a diagonal branch arising from near the aneurysm were found. Hence, PTFE-covered stents were not suitable for our case. A single mesh-covered stent (MGuard; InspireMD) has good deliverability and low risk of side branch occlusion. However, percent coverage area is around 20%. It is not known whether it is enough surface area to reduce flow into an aneurysm and to induce complete aneurysm thrombosis. Further investigation is warranted. Stent-assisted coil embolization of aneurysms has been well performed for wide-necked intracranial aneurysms.⁵ We were able to apply stent-assisted coil embolization of aneurysms for the coronary artery. In stent-assisted coil embolization of aneurysms, a microcatheter is usually placed in the aneurysm before stenting to prevent coil migration. However, stent deployment was very difficult in our case. We deployed the stent at first and then placed a microcatheter through the stent struts. We prevented coil migration by inflating a balloon in the stent at the orifice of the aneurysm only during coil delivery into the aneurysm. Meticulous care must be taken during manipulation of microcatheter, coils, or wires inside the aneurysm, because of the fragile nature of the saccular aneurysm. A bare-metal stent was implanted in our case. Restenosis after bare-metal stent implantation occurs in approximately 20%-40% of patients after 6-12 months. Drug-eluting stents reduce the rate of restenosis. However, they are associated with the risk of late stent thrombosis and were reported to cause coronary aneurysm formation.⁶ Currently, no consensus as to which stent is better has been established. In our case, no restenosis was observed 1 year after the index procedure.

Only a few reports on stent-assisted coil embolization for CAAs have been published.^7,8 Stent-assisted coil embolization may be a valuable method to treat selected patients with coronary aneurysms who have a suitable anatomy.

References

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From the Department of Cardiology, Kasugai Municipal Hospital, Kasugai, Aichi, Japan.

Disclosure: The authors have completed and returned the ICMJE Form for Dis- closure of Potential Conflicts of Interest. The authors report no conflicts of interest re- garding the content herein.

Manuscript submitted February 11, 2013, provisional acceptance given March 4, 2013, final version accepted April 3, 2013.

Address for correspondence: Akihiro Terasawa, MD, Department of Cardi- ology, Kasugai Municipal Hospital, 1-1-1 Takagi-cho, Kasugai, Aichi, 486-8510 Japan. Email: terasawa@lilac.ocn.ne.jp