Stent-Graft Exclusion of Multiple Symptomatic Coronary Artery Fistulae

Abstract

Coronary artery fistulae may be congenital or acquired abnormalities in which blood is shunted into a cardiac chamber, great vessel, or other structure, bypassing the myocardial capillary network. Patients with coronary artery fistulae may present with dyspnea, congestive heart failure, angina, endocarditis, arrhythmias, or myocardial infarction. Symptomatic patients must be treated in order to prevent such complications as sudden death or myocardial infarction. Surgery is the gold standard for closure of these lesions; however, an increasing number of reports have shown that percutaneous closure may be a safe and effective alternative. We report the successful percutaneous exclusion of multiple coronary artery-to-pulmonary artery fistulae by means of several balloon-expandable stent-grafts in a patient who had a history of coronary artery bypass surgery and symptoms of congestive heart failure.

Coronary artery fistula is an infrequent abnormality. The incidence of coronary artery fistula in the overall population is estimated to be 0.002%. Such a fistula is an incidental finding in 0.3% to 0.8% of patients who undergo diagnostic coronary angiography.^1–4

Most instances of coronary artery fistula are congenital. This abnormality is a result of communication between a coronary artery and a cardiac chamber, great vessel, or other vascular structure.⁵ Occasionally, clinical diagnosis of coronary artery fistula can be made by detecting a continuous heart murmur in the upper precordial area. Fistulae are usually detected by means of angiography. Coronary arteriovenous fistulae tend to get larger with age, so elective early closure is usually recommended in patients who have continuous murmurs or systolic murmurs with an early diastolic component.⁶

Although surgical closure has been described as the gold standard for coronary artery fistulae,⁷ closure during cardiac catheterization has been described as an alternative and less invasive procedure. Various percutaneous catheter devices have been used to close such fistulae, including coils, detachable balloons, alcohol foam, and double umbrellas.^6,8,9 In this report, we present the case of an adult patient with multiple symptomatic coronary artery–pulmonary artery (PA) fistulae and a significant left-to-right shunt that was diagnosed by coronary angiography and treated successfully by endovascular stent-graft deployment.

Case Report

In August 2004, a 47-year-old man with a history of systolic hypertension, dyslipidemia, smoking, and coronary artery bypass grafting (CABG, 3 years earlier) was admitted while experiencing atypical chest pain, exertional dyspnea (New York Heart Association functional class II), and fatigue. Three years before, in a general hospital in another city, he had undergone coronary angiography, which had shown severe 3-vessel disease, normal left ventricular (LV) size, and a global LV ejection fraction (LVEF) of about 0.50. He also had 2 small and faintly visible fistulae from the left anterior descending artery (LAD) and the right coronary artery (RCA) to the PA. Right heart catheterization and saturation studies were not performed. He had then undergone urgent CABG, and for an unknown reason the fistulae were not closed at the time of surgery.

His physical examination was remarkable for a cervical venous hum, a bounding pulse, and a grade 2/6 systolic murmur in his left sternal border. His heart rate was 95 beats/min, and he had a wide pulse pressure (blood pressure, 150/50 mmHg). His electrocardiogram showed no pathologic changes; however, his thallium scan revealed inferobasal ischemia. Transthoracic echocardiography (TTE) showed an enlarged LV (end-diastolic diameter, 60 mm; end-systolic diameter, 40 mm) with preserved systolic function (LVEF, 0.50); he had also mild, grade-1 diastolic LV dysfunction. Cardiac catheterization and selected coronary angiography, performed via the right femoral artery and vein, showed significant stenosis at the proximal portion of the LAD, insignificant stenosis at the mid portion of the left circumflex coronary artery, and occlusion at the mid portion of the RCA. The patient also had patent left internal mammary artery grafts to the LAD and patent saphenous vein grafts to the obtuse marginal artery and the RCA, with good distal runoff. In addition, coronary angiography showed 2 large coronary-to-PA fistulae arising from the proximal and mid portion of the LAD, and 1 large coronary-to-PA fistula protruding from the proximal portion of the RCA. All 3 fistulae were draining into the PA.

Right heart catheterization and an oximetry study showed a significant oxygen saturation step-up from the right ventricle to the PA, from 74% to 82% (8%), with an estimated left-to-right heart shunt of about 1.5:1, measured during a left and right heart saturation study. The patient also had mild pulmonary hypertension (PA pressure, 30/12 mmHg).

A 7F left Judkins 4 coronary guide catheter was used to pass a 0.014-inch floppy guidewire just distal to the mid-LAD fistulae. Then 2 coronary stent-grafts (Jostent®, Abbott Vascular, a division of Abbott Laboratories, Inc.; Abbott Park, Ill) (3 mm × 12 mm, followed by 3.5 mm × 12 mm) were deployed consecutively in the mid and then proximal LAD, covering the ostia of both fistulae (Fig. 1).

Fig. 1 Selected coronary angiography shows 2 large fistulae from the left anterior descending artery (LAD) to the pulmonary artery A) before stenting, B–E) during the procedure, and F) after deployment of 2 stents.

Next, the RCA was approached by means of a 7F right Judkins 4 guide catheter and the same coronary guidewire, to deliver a 3-mm × 12-mm Jostent to the site of the proximal RCA fistula. This stent-graft was then post-dilated using 18 atm of pressure with a 3.5-mm × 14-mm balloon (Cordis Corporation, a Johnson & Johnson company; Miami Lakes, Fla). Final angiography showed that all 3 fistulae were excluded (Fig. 2). The patient was discharged from the hospital 48 hours later, after an uneventful course, on a regimen of aspirin (325 mg daily) and clopidogrel (75 mg daily). At his6-month follow-up, he remained asymptomatic. The venous hum and systolic murmur had disappeared, his resting heart rate was 80 beats/min, and his blood pressure was 145/70 mmHg. He also had a slight decrease in his LV dimensions as evaluated by TTE (LV end-diastolic diameter, 55 mm; LV end-systolic diameter, 38 mm; and LVEF, 0.52).

Fig. 2 Large right coronary artery-to-pulmonary artery fistula clearly shown on selected coronary angiography A) before stenting, B) during the procedure, and C) after deployment of a stent-graft.

RAO = right anterior oblique; RCA = right coronary artery

Discussion

Congenital coronary–PA fistula is rare. The incidence ranges from 0.3% to 0.8% in patients who undergo coronary angiography.⁴ The vast majority of patients are asymptomatic. The natural course is development over time; however, a few cases of spontaneous closure have been reported. Patients usually become symptomatic during the 5th or 6th decade of life and may present with sudden cardiac death, myocardial ischemia, PA systolic hypertension, heart failure, arrhythmia, rupture, or endocarditis.^4,10

Due to the lack of some necessary data regarding our patient's previous angiography and heart surgery, we do not know why his fistulae were not closed at that time. Interestingly, it seems that after the necessary blood circulation to the distal part of the stenosed coronary vessels was maintained through the bypass grafts, there was a preferential circulation of blood from the proximal segments of the coronary arteries through the fistulae into the low-pressure PA, which enlarged the fistulae over time.

When symptoms occur, treatment is essential to avoid serious complications.¹⁰ Treatment of asymptomatic coronary fistulae is still under study.^11,12 In this case, due to the patient's young age, symptomatic congestive heart failure (with echocardiographic features), pulmonary hypertension, and the possibility of developing endocarditis, treatment was necessary.

There are 2 therapeutic options: surgical or endovascular exclusion. Several studies have shown that surgical closure is safe and effective. However, recurrence is estimated to range from 16% to 22%. Postoperative morbidity and mortality rates are low but increase with age.^6,7,12 Endovascular exclusion offers a less invasive option, which is especially attractive for use in patients who have undergone previous cardiac surgery. This exclusion may be accomplished by transcatheter embolic occlusion with alcohol foam, double-umbrella devices, or stainless-steel coils, or by implantation of a stent-graft. Embolization with stainless-steel coils has been used in most reported cases. Procedural success rates range from 50% to 92%.¹³ Inadequate or maldeployment has been reported in 23% of the cases and has resulted in myocardial infarction and sudden cardiac death.¹³ Persistence of flow in the fistulae has also been reported in up to 20% of the cases.^14–17 Like surgery, embolization using detachable balloons or stainless-steel coils is inadequate for plexus-like fistulae, which have numerous branches.¹³

Although a high incidence of in-stent restenosis or thrombus formation has been reported with the deployment of covered stents¹⁸—restenosis rates up to 35%, subacute thrombotic occlusion (despite using dual antiplatelet therapy) of 5% to 7%^19–21—we chose to use them because our patient had patent bypass grafts to the distal parts of the RCA and the LAD. To our knowledge, we have demonstrated for the 1st time the use of multiple stent-grafts for closure of multiple coronary–PA fistulae in a patient with a previous history of CABG.

We conclude that percutaneous stent-graft implantation is a safe and feasible method of treatment in patients with multiple coronary–PA fistulae and a distal coronary bed protected by previous CABG.

Acknowledgments

The authors wish to thank Kathryn G. Dougherty (peripheral vascular interventional research staff, Texas Heart Institute) and Dr. Shaheen Akhondzadeh (Deputy for Research Affairs, School of Medicine, Tehran University of Medical Sciences) for their assistance, advice, and support.