Coil Embolization of Large Coronary Artery Aneurysm Using Medtronic Concerto Detachable Coil System

Case report

A 78-year-old woman with a history of labile hypertension, arthritis, and hypothyroidism initially presented to clinic for evaluation of symptoms of progressive chest pain over several weeks. Chest pain was precordial pain that occurred at rest and exertion. Pain improved with sublingual nitroglycerin. Physical examination demonstrated a thin Caucasian female with normal peripheral pulses. She had no jugular venous distension, and she had normal heart sounds without murmurs, as well as clear lungs, and no edema.  She was tolerating a calcium channel blocker and angiotensin-converting enzyme inhibitor without incident. Electrocardiogram showed normal sinus rhythm with left ventricular hypertrophy.

Echocardiogram in the office showed moderate concentric left ventricular hypertrophy and there was a normal left ventricular ejection fraction with no pericardial or valvular disease. Nuclear stress test showed a small area of mild to moderate reversible perfusion defect in the inferolateral area. Given clinical and diagnostic findings, the patient was scheduled for elective cardiac catheterization. Angiographic findings revealed normal systolic function and tortuous epicardial arteries with patent left main, left anterior descending and right coronary arteries. The left circumflex and obtuse marginal branches were patent; however, the atrio-ventricular groove circumflex demonstrated a large 8-10 mm coronary aneurysm arising from a small branch with high-grade ostial stenosis (Figure 1).

With progressive chest pain, the patient returned for elective coil embolization of the circumflex coronary artery aneurysm three weeks later. The right femoral artery was accessed with a 6 French short sheath. The left main coronary artery was cannulated with a Medtronic Extra Backup (EBU) 3.5 guide catheter. Several unsuccessful attempts to cross the stenotic branch leading to the aneurysm were made using Whisper (Abbott Vascular) and ChoICE (Boston Scientific) coronary wires. The aneurysm was finally cannulated using an .017-inch inner lumen Echelon 10 microcatheter (Medtronic) with a Fielder XT wire (Abbott Vascular) (Figure 2). After wire removal, coil embolization was performed using a Medtronic Concerto detachable coil system. One NV-8-30-Helix 8 mm x 30 cm and subsequently, one NV-4-10-Helix 4 mm x 10 cm coil were used to occlude the aneurysm. Final angiograms showed successful coronary aneurysm coil embolization (Figure 3). The patient was monitored overnight uneventfully and discharged the following morning. On follow-up several weeks later, the patient had no further chest pain.

Discussion

Coronary artery aneurysms are uncommon findings typically diagnosed during coronary angiography. Coronary arteries are defined as aneurysmal when the diameter is at least 1.5 times larger than the adjacent segments or the largest coronary artery.  Coronary artery aneurysms greater than 20 mm are classified as giant aneurysms.^1,2 The most common cause in adults is atherosclerosis, but many etiologies are associated with coronary artery aneurysms, including vasculitic diseases, trauma, congenital, and iatrogenic.^3-5 Coronary artery aneurysms may result as complications of percutaneous coronary interventions, particularly after drug-eluting stent implantation.^4,6 Reported incidence varies from 1.5% to as high as 10%, most typically in males in the right coronary artery^.3,7 The natural history of coronary artery aneurysms is not well established, but some series have shown increased mortality.^7,8 Documented complications include thrombosis, distal embolization, vasospasm, fistula, and rupture.^3-5,7 Rates of complication may be related to etiology, size, rate of growth, and pseudoanerysm.^1,2 Polyarteritis nodosa, for instance, is reported to have up to 6% of cases complicated by rupture.¹

Though optimal treatment is still uncertain at this time, options include medical, surgical and endovascular.^1,3-6 Endovascular techniques such as covered stents and coil embolization are presently off-label for coronary aneurysms.^3-6 Regardless of modality, the treatment goal is to prevent rupture, bleeding or embolization of aneurysmal thrombus. Coil embolization of aneurysms lead to occlusion of the aneurysm with formation of organized thrombus, fibrosis, and eventual endothelialization.⁹ Previous studies have reported coil embolization of coronary artery aneurysms in the setting of stent-assisted deployment.^10-13

In regards to this patient, treatment was elected due to symptomatic nature. Deployment of covered stent was decided against due to vessel size and tortuosity. We were concerned that delivering a covered stent would be challenging and would have a high probability of additional side branch occlusion adjacent to the feeder branch of the aneurysm.  

The Medtronic Concerto system is a catheter-based detachable coil embolization system typically used in aneurysms and hemorrhages of the peripheral vasculature. The coils are nylon- or polyglycolic/polylactic acid-coated with polypropylene strand LatticeFX technology to enhance thrombus formation upon delivery. The low-profile nylon coils are compatible with as small as .0165-inch microcatheters. The target space is wired and cannulated with a catheter in a standard fashion. The coil is advanced into the target area and may be retracted until detached, even if fully deployed. The ball-and-socket mechanism of the detachment system allows free rotation of the coil. When optimal positioning is achieved, the delivery system is advanced until the coil alignment marker of the pusher is distal to the marker band of the proximal end of the catheter. The pusher is then retracted to approximate the alignment marker and proximal catheter marker. The thumb slide of the pusher is retracted, disengaging the release element from the coil’s proximal end ball, instantly detaching the coil. The delivery system is then withdrawn. In this case, we utilized a second coil for optimal aneurysm occlusion.

This device was deemed a reasonable choice in this case based on anatomical considerations. To date, we believe this is the first case report of lone coil embolization of coronary artery aneurysm using the Medtronic Concerto system.

Conclusion

The optimal therapy for coronary aneurysms is uncertain. In high-risk anatomies unsuitable for stent-assisted coiling, use of Medtronic Concerto system may be a reasonable therapy.

References

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This article received a double-blind review from members of the Cath Lab Digest Editorial Board.

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

The authors can be contacted via Dr. Paul Stewart at dastewar@alum.unthsc.edu