Transcatheter Embolization of Recanalized Coronary Artery Fistula with Nit-Occlud Device

ABSTRACT: Congenital coronary artery fistula is a rare anomaly with varying symptomatology that may be addressed with surgical or interventional closure. Recanalization after complete occlusion of a coronary artery fistula has only been reported after surgical but not after interventional closure. We present a case of coronary artery fistula recanalization after angiographically documented complete transcatheter occlusion with Gianturco coils. The fistula was successfully managed by transcatheter implantation of a Nit-Occlud system, originally designed for interventional closure of patent ductus arteriosus. J INVAS CARDIOL 2004;16:215–217 Key words: coronary artery fistula, recanalization, transcatheter occlusion Congenital coronary artery fistula (CAF) occurs in approximately 1 in 50,000 congenital heart disease patients and 1 in 500 coronary angiography patients.¹ While often asymptomatic in children, CAF may be associated with significant complications.² Acquired CAF may occur as a complication of congenital heart disease or bypass surgery, coronary angioplasty, stent placement or heart biopsy.³ After the initial report of successful surgical repair in 1947, surgery has been the traditional approach4 until the last few years, when various interventional techniques using coils, stents, balloons and umbrella devices have been increasingly used with very encouraging results.⁵ Recanalization after catheter occlusion without initial residual shunt has not been reported to date in the literature.⁶ We describe a case of CAF recanalization after complete coil occlusion, successfully managed with transcatheter implantation of a Nit-Occlud system, originally designed for interventional occlusion of patent ductus arteriosus. Case Report. A 4-year-old asymptomatic girl with a continuous murmur, normal electrocardiogram and mild cardiomegaly on chest radiograph was referred to our institution. Echocardiography demonstrated a mildly dilated, well-functioning left ventricle and a dilated left coronary artery with a long tortuous vessel behind the aortic root draining into the right atrium. Hemodynamic evaluation, after informed written consent, revealed Qp to Qs ratio of 1.4 with normal pulmonary artery pressure and resistance. Angiography depicted normal right coronary artery anatomy and a dilated left main coronary artery giving rise to normal left anterior descending and circumflex system and continuing horizontally as an aneurysmal and tortuous vessel with no additional branches and significant flow draining into the right atrium. The fistula was dilated at 14 mm with two aneurysmal dilatations over 20 mm and tapering to 7 mm close to the drainage site, which measured 2–3 mm (Figure 1). Two 8 mm and two 15 mm Gianturco coils were deployed in the distal end of the fistula with complete occlusion on angiography (Figure 2). The murmur disappeared, cardiac enzymes, electrocardiogram and myocardial perfusion study remained normal, and echocardiography confirmed absence of flow through the fistula. The patient was discharged home on no medication. A soft continuous murmur reappeared 6 months later on physical examination. Echocardiography showed mild residual flow through the previously identified drainage site into the right atrium, suggestive of recanalization. The patient remained asymptomatic over the next 5 years, although the murmur became progressively harsher and louder and the flow seen by echocardiography into the right atrium progressively increased to moderate. Repeat cardiac catheterization at 9 years of age, after informed written consent, revealed Qp to Qs ratio of 1.2 with normal ventricular dimensions and pulmonary vascular resistance. Angiography demonstrated a fistula with the same morphology and residual flow into the right atrium through the previously placed coils at its distal end (Figure 3). A 9 x 6 mm Nit-Occlud coil system (a nitinol-based spiral device with double-disk pyramid configuration designed for interventional patent ductus arteriosus occlusion; PFM, Cologne, Germany) was deployed in the proximal horizontal portion of the fistula distal to the documented origin of the normal left anterior descending and circumflex arteries, without complications. Minimal residual shunt without audible murmur was noted after placement by echocardiography as well as angiography (Figure 4), while electrocardiogram and myocardial perfusion study remained normal. Echocardiography 2 weeks post-procedure showed the coils and Nit-Occlud device in the same position without residual flow through the fistula. On follow-up 18 months after the procedure, the patient remains asymptomatic, with absence of flow through the fistula or any evidence of recanalization. Discussion. Patients with small, clinically silent CAF diagnosed incidentally with echocardiography who have normal electrocardiogram and chest radiograph may be followed conservatively with up to 23% spontaneous closure rate.⁷ However, significant CAF has been associated with morbidity and mortality due to “coronary steal” leading to myocardial ischemia and angina, myocardial infarction, congestive heart failure, bacterial endocarditis, fistula rupture and even death, especially in the adult population.² Assessment of symptoms in infants and young children may be misleading and therapeutic closure should probably be undertaken even in asymptomatic patients with clinically, electrocardiographically or roentgenographically abnormal findings.⁴ Surgical ligation, necessitating cardiopulmonary bypass in a significant number of cases, has yielded very good results, but is not devoid of complications, such as transient arrhythmias and ischemic changes, stroke and even death due to myocardial infarction.⁵ Various interventional occlusion techniques have been increasingly utilized in recent years as alternatives to surgery in an attempt to avoid sternotomy and cardiopulmonary bypass and to minimize morbidity and hospital stay. Transcatheter embolization has been associated with uncommon complications, such as transient ischemic electrocardiographic changes and arrhythmias, device embolization and myocardial infarction,⁵ as well as 1 reported procedural death due to device recoil into the left main coronary artery.³ Recanalization of CAF has only been reported once 7 years after surgical closure in a patient with spontaneous disappearance 3 years later, but without in-depth description of the event.⁸ Recanalization of CAF has not been reported in the literature after complete interventional occlusion. There is a single report on a patient with CAF occluded with an umbrella device and trace residual flow, in which flow increased by echocardiography and led to repeat interventional occlusion.⁵ This is the first report of recanalization of a previously completely occluded CAF, months after angiography, echocardiography and disappearance of murmur documented complete closure. It is important to note that, in agreement with the above-mentioned case,⁵ both the murmur characteristics and echocardiography suggested progressively increasing flow through the recanalized tract over the 5-year follow-up period of the recanalized fistula without intervention. To our knowledge, this is the first report of successful transcatheter closure of a CAF by implantation of a Nit-Occlud device, originally designed for interventional patent ductus arteriosus closure.⁹ The device was implanted distal to the origin of the normal left coronary artery system, but relatively proximally within the fistula, attempting to reduce the length of the cul-de-sac remaining after occlusion of the fistula. The presence of a dilated and tortuous cul-de-sac still in contact with the circulation may increase the incidence of new thrombus formation within it and its migration to normal coronary vessels, causing ischemia or infarction, as has been previously reported.¹⁰ Close long-term follow-up after transcatheter or surgical closure of CAF is very important in order to recognize possible recanalization, as in our patient, and complications such as left ventricular aneurysm8 or myocardial infarction,¹⁰ which may occur years after CAF occlusion. Medical management after complete CAF occlusion remains controversial in the literature, while most studies do not suggest anticoagulation treatment. In view of the persistence of the fistulous cul-de-sac and coronary artery dilation,^8–11 as well as the reported incidence of myocardial infarction due to new thrombus formation in the dilated cul-de-sac 10 years after surgical repair,10 it may be prudent to treat patients, especially those with persistent vessel dilation, with low-dose aspirin as some authors advocate.¹¹ Due to the previous recanalization event, our patient was not initially anticoagulated, but was placed on low-dose 5 mg/kg aspirin after the first year of follow-up. In summary, we report a case of recanalization of a CAF after previous complete occlusion with coils. This case was successfully managed by transcatheter implantation of a Nit-Occlud system, originally designed for interventional closure of patent ductus arteriosus.