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Transcatheter Closure of a Rare Case of Aorto-Right Ventricular Tunnel with Single Coronary Artery
December 2010
Aorto-ventricular tunnel is a rare congenital malformation, in particular when the tunnel communicates with the infundibulum of the right ventricle (RV). Only 8 cases of aorto-right ventricular tunnel (ARVT) have been reported in the English literature (Table 1).1–8 Occasionally, patients are asymptomatic and present with a heart 
murmur and cardiac enlargement, but most suffer heart failure in the first year of life. It must be distinguished from other lesions that cause rapid run-off of blood from the aorta and produce cardiac failure. Optimal management of symptomatic aorto-ventricular tunnel consists of diagnosis by echocardiography, complimented with cardiac catheterization to elucidate coronary arterial origins or associated defects, and prompt percutaneous or surgical intervention. We report a first case of successful transcatheter closure of ARVT with a single coronary artery with an absent right coronary artery ostium in a young child.
Case report. A 5-year-old girl was referred to us with continuous machinery murmur of a patent ductus arteriosus (PDA) over the precordium. The patient had increasing exertional dyspnea and easy fatigability for the past few months. She required repeated hospitalizations for recurrent respiratory infections since the age of 6 months. She never had any history of chest pain.
On examination she was acyanotic and without pallor or respiratory distress. The patient’s body weight was 15.5 kg, her height was 101 cm and her vital signs were normal. Cardiac examination revealed a muffled first and second heart sound with a continuous grade 3/6 murmur that was maximally heard over the right parasternal area in the third and fourth intercostals spaces. An electrocardiogram (ECG) showed sinus rhythm with QRS axis + 70 in the frontal plane. A chest X-ray showed a cardiothoracic ratio of 0.65 with bilateral hilar prominence and increased lung vascularity. Echocardiography revealed situs solitus with atrioventricular and ventriculoarterial concordance. The atrial septum was intact with normal pulmonary venous drainage. We noted an abnormal, continuous, high-velocity L→R flow into the RV with a peak velocity of 3.6 m/sec. Continuous Doppler signals from the ascending aorta just above the right coronary sinus to the RV were detected (Figure 1A ). Both right and left ventricles were dilated.
Cardiac catheterization was performed to confirm the diagnosis and possibly attempt closure of the tunnel. Right- and left-heart catheterization confirmed the diagnosis of ARVT, which originated from the ascending thoracic aorta (Figure 2). Hemodynamic data showed Qp:Qs to be 3.2:1, with mild elevation of pulmonary artery pressures (45/22, mean 36 mmHg). 
Angiographic morphology of the defect showed a narrow neck and short course with direct opening into the RV. Aortic root angiography showed a normal left coronary ostium, while the right coronary ostium could not be visualized. However, in selective coronary angiography of the left system, the entire coronary system was visualized from a single ostium located at the left sinus. The left coronary artery (LCA) was seen to split off from a short common trunk and to continue into a left anterior descending artery (LAD) and circumflex branches. The right coronary artery (RCA) and distal branches were found to fill directly from the left system (Figure 3).
A 6 French (Fr) right Judkin’s catheter was engaged at the origin of the tunnel and a 0.035 inch exchange-length guidewire (Terumo, Inc., Japan) was advanced through the tunnel into the pulmonary artery via the RV and then snared into the femoral vein to achieve an arteriovenous loop. An 8 Fr Mullin’s sheath (Cook, Inc., Bloomington, Indiana) was advanced
from the femoral vein into the RV and then across the tunnel into the ascending aorta. A 10 x 8 mm Cardi-o-Fix (Starway Medical Technology, Inc., Beijing, China) duct occluder device was deployed in the narrow portion of the tunnel and released after aortic root check angiograms. Transesophageal echocardiography and repeat angiography performed 10 minutes after the release showed optimum position of the device with very little intra-device foaming (Figure 1B, Figure 4). 
The patient’s post-procedure ECG and cardiac enzyme (creatinine-kinase MB and troponin I) readings were normal. She was discharged after 48 hours. At 8-month follow up, she had a remarkable reduction in symptoms of congestive heart failure, no residual flow across the tunnel and normalization of her estimated pulmonary artery pressures. Her adenosine stress Tc99m single-photon emission computed tomographic scan (SPECT) revealed uniform myocardial isotope uptake without any segmental hypoperfusion defects. Gated SPECT revealed good ventricular function with normal wall motion and wall thickening in all segments.
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From the Department of Cardiology, U. N. Mehta Institute of Cardiology & Research Centre, Civil Hospital Campus, Asarwa, Ahmedabad, Gujarat, India.
The authors report no conflicts of interest regarding the content herein.
Manuscript submitted June 23, 2010, provisional acceptance given July 6, 2010, final version accepted August 24, 2010.
Address for correspondence: Dr. Bhavesh M. Thakkar, 9, Shreedhar Society, Thakkarnagar Approach, Bapunagar, Ahmedabad 380024, Gujarat, India. E-mail: bthakkarin@yahoo.co.in
murmur and cardiac enlargement, but most suffer heart failure in the first year of life. It must be distinguished from other lesions that cause rapid run-off of blood from the aorta and produce cardiac failure. Optimal management of symptomatic aorto-ventricular tunnel consists of diagnosis by echocardiography, complimented with cardiac catheterization to elucidate coronary arterial origins or associated defects, and prompt percutaneous or surgical intervention. We report a first case of successful transcatheter closure of ARVT with a single coronary artery with an absent right coronary artery ostium in a young child.
Case report. A 5-year-old girl was referred to us with continuous machinery murmur of a patent ductus arteriosus (PDA) over the precordium. The patient had increasing exertional dyspnea and easy fatigability for the past few months. She required repeated hospitalizations for recurrent respiratory infections since the age of 6 months. She never had any history of chest pain.
On examination she was acyanotic and without pallor or respiratory distress. The patient’s body weight was 15.5 kg, her height was 101 cm and her vital signs were normal. Cardiac examination revealed a muffled first and second heart sound with a continuous grade 3/6 murmur that was maximally heard over the right parasternal area in the third and fourth intercostals spaces. An electrocardiogram (ECG) showed sinus rhythm with QRS axis + 70 in the frontal plane. A chest X-ray showed a cardiothoracic ratio of 0.65 with bilateral hilar prominence and increased lung vascularity. Echocardiography revealed situs solitus with atrioventricular and ventriculoarterial concordance. The atrial septum was intact with normal pulmonary venous drainage. We noted an abnormal, continuous, high-velocity L→R flow into the RV with a peak velocity of 3.6 m/sec. Continuous Doppler signals from the ascending aorta just above the right coronary sinus to the RV were detected (Figure 1A ). Both right and left ventricles were dilated.
Cardiac catheterization was performed to confirm the diagnosis and possibly attempt closure of the tunnel. Right- and left-heart catheterization confirmed the diagnosis of ARVT, which originated from the ascending thoracic aorta (Figure 2). Hemodynamic data showed Qp:Qs to be 3.2:1, with mild elevation of pulmonary artery pressures (45/22, mean 36 mmHg). 
Angiographic morphology of the defect showed a narrow neck and short course with direct opening into the RV. Aortic root angiography showed a normal left coronary ostium, while the right coronary ostium could not be visualized. However, in selective coronary angiography of the left system, the entire coronary system was visualized from a single ostium located at the left sinus. The left coronary artery (LCA) was seen to split off from a short common trunk and to continue into a left anterior descending artery (LAD) and circumflex branches. The right coronary artery (RCA) and distal branches were found to fill directly from the left system (Figure 3).
A 6 French (Fr) right Judkin’s catheter was engaged at the origin of the tunnel and a 0.035 inch exchange-length guidewire (Terumo, Inc., Japan) was advanced through the tunnel into the pulmonary artery via the RV and then snared into the femoral vein to achieve an arteriovenous loop. An 8 Fr Mullin’s sheath (Cook, Inc., Bloomington, Indiana) was advanced
from the femoral vein into the RV and then across the tunnel into the ascending aorta. A 10 x 8 mm Cardi-o-Fix (Starway Medical Technology, Inc., Beijing, China) duct occluder device was deployed in the narrow portion of the tunnel and released after aortic root check angiograms. Transesophageal echocardiography and repeat angiography performed 10 minutes after the release showed optimum position of the device with very little intra-device foaming (Figure 1B, Figure 4). 
The patient’s post-procedure ECG and cardiac enzyme (creatinine-kinase MB and troponin I) readings were normal. She was discharged after 48 hours. At 8-month follow up, she had a remarkable reduction in symptoms of congestive heart failure, no residual flow across the tunnel and normalization of her estimated pulmonary artery pressures. Her adenosine stress Tc99m single-photon emission computed tomographic scan (SPECT) revealed uniform myocardial isotope uptake without any segmental hypoperfusion defects. Gated SPECT revealed good ventricular function with normal wall motion and wall thickening in all segments.
Discussion
Aorto-ventricular tunnel is a congenital, extracardiac channel, which connects the ascending aorta at or above the sinotubular junction to the cavity of the left or right ventricle. The reported incidence varies from 0.5% of fetal cardiac malformations to 9–12 Associated defects, usually involving the proximal coronary arteries or the aortic or pulmonary valves, are present in nearly half of the cases.1,2,4,6 ARVT is an abnormal pathway that originates above or in the upper portion of the right sinus of Valsalva, just to the left of the orifice of the RCA and enters the infundibulum of the RV. This anomaly, similar to the more common aorto-left ventricular tunnel, is believed to be related to a congenital weakness in the region of the right sinus of Valsalva. Associated abnormal origin or absence of the right or left coronary ostium has been reported. Hemodynamically, the anomaly produces a left-to-right shunt with resulting pressure and volume overload of the RV. Ruptured sinus of Valsalva (RSOV) is also an aorto-ventricular communication and a resultant left-to-right shunt produces similar hemodynamic consequences as in the case of ARVT. However, the clinical presentation is typically of acute onset during the second or third decade of life, and coronary anomalies are not described in association with RSOV, in contrast to ARVT. Echocardiography helps to establish a correct diagnosis by demonstrating the two ends of the tunnel connecting the aorta and the (often dilated) RV, and by obtaining high-velocity continuous Doppler-flow signals in the tunnel. Angiography remains an important adjunctive diagnostic technique to confirm the diagnosis and is particularly helpful in excluding coronary artery abnormalities. Before any planned intervention involving the aortic root is undertaken, every effort should be made to delineate the coronary artery anatomy, because failure to do so in cases of an aberrant origin of a coronary artery may prevent successful correction or can change the therapeutic approach, as in our case.4 ARVT should be repaired as early in life as possible to minimize damage to the RV and to avoid the development of obstructive pulmonary vascular disease. Long-term outcomes are unfavorable in those patients treated conservatively.12,13 Of the 8 reported patients, 7 were operated on and only 4 were long-term survivors.1–6 Interestingly, 4 of 8 reported patients had an associated coronary anomaly, as in our case. The repair should be individualized either by surgical or transcatheter closure. Conventionally, transcatheter closure is not considered a feasible option owing to the proximity of the tunnel to the coronary ostium or aortic valve leaflets and an associated coronary anomaly necessitating surgery. However, as per the definition of a normal RCA by Paolo Angelina’s group, a coronary anomaly in our case appeared to be a clinically benign single coronary artery and should more properly be called a single coronary ostium because all the coronary arteries were present, though they were anomalous in their origin and course.14 Surgical or interventional revascularization in patients with an anomalous RCA is probably justified only in the presence of: 1) disabling symptoms and/or a high risk of sudden death; 2) area stenosis > 50%; 3) a large dependent myocardial territory; and 4) reversible ischemia according to a nuclear stress test.14 Surgical revascularization by itself is not risk-free, and even the simplest of pediatric heart operations carries risks of neurologic, myocardial and other organ injury as well as death. Furthermore, patency rates at 10 years for internal mammary grafts and saphenous vein grafts of 78% and 36%, respectively,15,16 virtually guarantee the need for re-operation in most patients, with its concomitant risks. In the absence of a defined natural history of the congenital coronary anomaly, a definite indication (rest or inducible ischemia) and an advantage for surgical management of an asymptomatic anomalous RCA, we believe that the incidental presence of a single coronary artery and left main trunk does not constitute a definite indication for surgical revascularization, particularly in such young patients. Therefore, transcatheter closure was performed under continuous imaging. In the last few years, there have been reports of successful transcatheter closure of selected patients with ALVT.13 Following a detailed literature search, this is the first and only case report of ARVT with an angiographically documented single coronary artery and an absent RCA ostium, which was successfully treated by transcatheter closure using a duct occluder.Conclusion
This case highlights the need for elucidating the exact coronary artery origins by angiography in all patients with aorto-ventricular communications before undertaking any therapeutic interventions. Our report demonstrates the feasibility of successful transcatheter management of this clinically and embryologically intriguing rare anomaly.References
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