Aorto–Left Ventricular Tunnel Originating from the Left Coronary Sinus with Aortic Aneurysm in an 11-Year-Old Boy

Abstract

Aorto–left ventricular tunnel, characterized by extracardiac communication between the ascending aorta and left ventricle, is a very rare congenital condition. Although some affected infants remain asymptomatic until adulthood, most present with symptoms of heart failure during their first year of life. We report the case of an 11-year-old boy who had coexisting abnormalities: an aorto–left ventricular tunnel originating from the left coronary sinus, and an ascending aortic aneurysm. The patient underwent on-pump surgical correction and was in New York Heart Association functional class I status a year later. We also review the nature of this rare condition.

Aorto–left ventricular tunnel (ALVT) is a rare congenital cardiac malformation: approximately 130 cases have been reported. In most cases, the ALVT is found above the right sinus of Valsalva; less often, it originates from a region above the left sinus of Valsalva. Associated coronary artery anomalies have been found in 45% of patients with ALVT.^1–3 Most patients are diagnosed with an ALVT during early infancy; however, a few initial diagnoses have been reported in adults.^2,3 An ALVT associated with an ascending aortic aneurysm in a child or young adult is extremely rare—ascending aortic aneurysms usually accompany congenital heart diseases such as bicuspid aortic valve or tetralogy of Fallot, or connective-tissue diseases such as Marfan, Ehlers-Danlos, and Loeys-Dietz syndromes.⁴ An ascending aortic aneurysm can also develop after the surgical correction of some congenital heart diseases.⁵ We report the case of a child who had concurrent conditions: an ALVT that originated from the left coronary sinus, and an ascending aortic aneurysm.

Case Report

In May 2010, an 11-year-old boy was referred to our clinic with a heart murmur. He had mild fatigue, no prominent cardiac complaint, and a sedentary lifestyle. His family medical history included no cardiac disease, connective-tissue disease, consanguinity, or sudden death.

Physical examination revealed a heart rate of 120 beats/min, a respiratory rate of 22 breaths/min, and a blood pressure of 110/50 mmHg. A thrill was heard on the left precordium, and a 3–4/6 diastolic murmur radiated along both sternal borders.

Chest radiographs showed cardiomegaly. An electrocardiogram revealed sinus tachycardia, a heart rate of 125 beats/min, a negative T wave, and ST depression in leads V₄ through V₆. Transthoracic and transesophageal echocardiograms showed an ascending aortic aneurysm, aortic root dilation, and an abnormal communication between the aorta and the left ventricle (LV). This tunnel-like structure, originating from the left coronary sinus, was behind and to the left of the aorta. There was severe aortic valve insufficiency. The LV was dilated and had increased apical trabeculation. The patient's LV fractional shortening (30%) and ejection fraction (0.50) were below normal, and the LV end-diastolic diameter (54 mm) was larger than normal (Fig. 1). Computed tomographic angiography (CTA) was performed to evaluate the aortic arch, coronary arteries, and location of the tunnel. The results verified an ascending aortic aneurysm 5.3 cm in diameter, a tunnel originating from the left coronary sinus and passing to the back and left of the aorta, LV dilation, and increased LV trabeculation. The coronary arteries were normal; however, the left coronary button was mildly compressed by the proximal tunnel (Fig. 2).

Fig. 1 Transthoracic echocardiograms show A) the aorto–left ventricular tunnel (arrow) on the left side of the left coronary cusp, and B) prominent tunnel insufficiency. C) Transesophageal echocardiogram shows the tunnel on the left side of the left coronary cusp.

AAo = ascending aorta; Ao = aorta; ALVT = aorto–left ventricular tunnel; LV = left ventricle

Fig. 2 Computed tomographic angiograms show A) the ascending aortic aneurysm, B) the aorto–left ventricular tunnel (ALVT) arising from the left coronary sinus, and C) coronary arterial compression by the proximal side of the tunnel.

AV = aortic valve; LCA = left coronary artery; LCC = left coronary cusp; LV = left ventricle; NCC = noncoronary cusp; RCC = right coronary cusp

The patient was started on anticongestive therapy with digoxin, diuretics, and angiotensin-converting enzyme inhibitors. He was scheduled for surgical repair of the ALVT and ascending aortic aneurysm.

The patient was placed on cardiopulmonary bypass (CPB) with moderate hypothermia. The distal aortic arch and right atrium were cannulated. After aortic cross-clamping, the ascending aorta was opened, and warm-blood cardioplegic solution was administered directly to the coronary ostia. The tunnel was detected posterior and to the left of the aorta, close to the left main coronary artery, approximately 1 cm outside the aortic annulus. The aortic root was dilated and thin-walled (Fig. 3). The aortic annulus was severely distorted, and the aortic leaflets were thickened. The leaflets seemed to be competent despite prolapse of the right coronary cusp, and valve-sparing aortic root replacement was performed. The ascending aorta was resected. Both coronary ostia were prepared as buttons; however, the left coronary button could not be resected adequately because of the proximity of the tunnel, so it was instead anastomosed to the aortic graft with an 8-mm Dacron interposition graft. The ALVT was closed with use of an aortic graft with interrupted Dacron polypropylene sutures. A biopsy sample was taken from the aortic wall. After CPB was ended, transesophageal echocardiography showed moderate-to-severe aortic insufficiency, so CPB was resumed, and the aortic valve was replaced with a mechanical valve.

Fig. 3 Intraoperative photograph shows the aorto–left ventricular tunnel (arrow).

Pathologic examination of the aortic valve sample yielded no specific findings. The patient's postoperative period was uneventful. He was discharged on anticongestive therapy on the 10th postoperative day. Echocardiograms 2 weeks later showed improved LV function (ejection fraction, 0.65; fractional shortening, 33%; and end-diastolic diameter, 43 mm) and a normally functioning prosthetic valve. The anticongestive therapy was tapered to zero after 3 months. One year postoperatively, CTA of the aortic arch and graft revealed only mild aortic dilation in comparison with preoperative images (Fig. 4). As of December 2012, the patient remained in New York Heart Association functional class I and had been taking only warfarin since September 2010.

Fig. 4 Computed tomographic angiogram 1 year after surgery shows the mechanical aortic valve, a mildly dilated ascending aorta, and normal left ventricular structure.

Discussion

Although the cause of ALVT is uncertain, explanatory hypotheses include an abnormal coronary artery, the early or intrauterine rupture of a sinus of Valsalva aneurysm, malformation of the distal bulbus cordis, early aortic dissection similar to that in Marfan syndrome, or the persistence of embryonic remainders of the 5th aortic arch. The failure of extracardiac tissue planes that separate the cushions forming the facing aortic and pulmonary sinuses with their respective valvular leaflets might lead to the formation of an ALVT.^1,5 In patients who underwent cardiac catheterization during a 35-year period, the incidence of ALVT was estimated to be 0.05%.²

Hovaguimian and colleagues⁵ defined 4 anatomic types of ALVT: a slit-like opening at the aortic end with no valve distortion in type 1 (prevalence, 24%), a large extracardiac aneurysm in type 2 (44%), an intracardiac aneurysm of the septal portion of the tunnel with or without right ventricular outflow tract obstruction in type 3 (24%), and a combination of types 2 and 3 in type 4 (8%). In most cases, the aortic orifice of the tunnel arises from the right coronary sinus and is on the anterolateral side of the ascending aorta.⁵ The ALVT rarely arises from the left coronary sinus, and there are only a few reports of this presentation.^6,7 In our patient, the aortic orifice of the tunnel originated from the left coronary sinus, and the tunnel was posterolateral to the ascending aorta. The presentation differed from the classifications of Hovaguimian and colleagues in that an ascending aortic aneurysm accompanied our patient's ALVT. The most common reason for ascending aortic aneurysms in children is a connective-tissue disease, in particular Marfan syndrome⁴; however, our patient had no Marfan traits.

The clinical presentation of ALVT varies depending upon the compression of the coronary arteries, the presence of right or left ventricular outflow obstruction, and the diameter of the tunnel.^1–3 Congestive heart failure frequently develops during the first year of life; however, nearly half of patients with ALVT remain asymptomatic.^1,8 Although our 11-year-old patient had aortic valve distortion, coronary arterial compression by the proximal end of the tunnel, and impaired cardiac function, his only symptom was mild fatigue—perhaps because of his sedentary, nonathletic lifestyle.

Early surgical closure of the tunnel is suggested to prevent severe aortic regurgitation, even if the patient is asymptomatic. According to reported results of ALVT operations, surgery is most successful during a patient's early infancy. Even in asymptomatic patients, repairs during the first 6 months of life have resulted in more successful subsequent normalization of LV size and function.1,2,8,9 Even though our patient underwent correction at 11 years of age, his LV systolic function was greatly improved only 3 months postoperatively, and his anticongestive medication was tapered and discontinued.

The treatment of choice is either patch closure or primary repair of the aortic orifice. Thus, the coronary circulation is not compromised, and left or right ventricular outflow obstruction is prevented or relieved. Most ALVT cases are treated by means of transaortic patch closure of the aortic end, and by placement of a second patch through the tunnel itself to close the ventricular orifice and support the aortic valve.2,5,9,10

Our patient's ascending aortic aneurysm complicated the surgery: the ALVT was on the left and outside of the aortic valve annulus during graft replacement of the aorta. The left coronary button could not be freed for direct reimplantation because of its proximity to the ALVT. We first planned valve-sparing aortic root replacement, but this was not feasible because of severe distortion of the aortic root, leaflet prolapse, and perhaps technical errors.

A tunnel originating from the left coronary sinus is very rarely diagnosed. It can be accompanied by aortic root dilation and an ascending aortic aneurysm, either of which might complicate surgical repair. Although echocardiography is the gold standard for diagnosis, CTA is necessary to determine the diameter of the ascending aortic aneurysm, delineate the morphology of the ALVT, and show the condition of the aortic arch and its branches. An ALVT can lead to progressive LV failure and aneurysmal dilation of the ascending aorta. We found that cardiac function and dilation improved in a short time after surgical correction, even in a patient as old as 11 years.