Unicuspid Aortic Valve in Infant.

The unicuspid aortic valve (UAV) is a very rare congenital anomaly, which usually presents as aortic stenosis, incompetence, or a combination of both. Here, we present a case of UAV with moderate aortic stenosis detected by transthoracic echocardiography in the infant.

INTRODUCTION

The unicuspid aortic valve (UAV) is a rare form of congenital heart disease, mainly confused with bicuspid aortic valve and presents with aortic stenosis [Figures 1–4]. Many affected patients require intervention for severe stenosis in infancy or childhood. Others may remain hemodynamically stable for several years before they require intervention, especially in the unicommissural form.[12] Here, we present a case of UAV with moderate aortic stenosis detected by echocardiography in the infant.

Figure 1

Transthoracic echocardiography at parasternal short axis view shows posteriorly situated eccentric aortic valve orifice in systole

Figure 4

Parasternal long axis view shows dome-shaped configuration of aortic valve during diastole

Transthoracic echocardiography at parasternal short axis view shows the one lateral commissural attachment to the aorta posteriorly in diastole

Parasternal long axis view shows dome-shaped configuration of aortic valve during systole

CASE REPORT

An 8-month-old child was referred for cardiac murmur evaluation. He was asymptomatic. Absence of failure to thrive and no signs of congestive heart failure on clinical evaluation. On general examination, the child was afebrile, pallor, no cyanosis or clubbing, and jugular venous pressure was not raised. Vitals were stable. Physical examination revealed a 4/6 harsh systolic murmur at the right upper sternal border. Examination of other systems was normal. Chest X-ray was normal. Electrocardiogram showed sinus tachycardia. Transthoracic echocardiography revealed a posteriorly situated eccentric aortic valve orifice extending to the annulus in systole. It showed noncalcified, unicuspid unicommissural aortic valve with moderate aortic stenosis (peak pressure gradient of 50 mmHg). Biventricular contractility and segmental wall motion were normal. Mildly dilated left ventricle with normal size left atrium. The size of the aortic annulus (08 mm), aortic root (13.7 mm) and ascending aorta (12.4 mm). No other associated congenital heart disease was noted [video 1–2].

DISCUSSION

The aortic valve develops from three tubercles that are converted into thin valve cusps and sinuses of valsalva by a process of excavation. A UAV is formed by the fusion of all the three cusps. The free edge of the single leaflet originates from the single attachment. It then proceeds across the orifice without additional contact with the aorta. Then, it bends on itself and returns to the point of origin. UAV may have a central opening (no true commissure/acommissural) or an eccentric orifice (unicommissural) as in our case. The acommissural type has no lateral attachment to the aorta with a central orifice, and the unicommissural type has one attachment with an eccentric orifice that could be linear (like an exclamation mark), triangular, oval, or “tear drop” shape.[12] The acommissural form usually causes severe stenosis and is highly symptomatic at a neonatal age. The UAV is a rare congenital malformation seen in 0.019% of patients during the echocardiographic evaluation and in 5.59% of patients during aortic valve replacement.[23] Severe aortic stenosis or mixed stenosis and regurgitation are the predominant disorder that accompanies patients with a UAV.[4] It presents far more often in males than females, often in the third decade of life when aortic stenosis becomes clinically significant. The UAV is prone to be associated with dilatation or dissection of the aorta, involving the aortic root, ascending aorta, or aortic arch, which typically requires surgical intervention.[567] Other associated disorders include aortic coarctation, an aberrant right subclavian artery, and a single coronary artery and ventricular septal defects (VSDs). The importance of an early diagnosis of UAV lies in its risk of sudden cardiac death and association with other congenital anomalies, such as patent ductus arteriosus (PDA), VSD, anomalous coronary arteries, and coarctation of the aorta. Recently, magnetic resonance imaging, cardiac computed tomography, and multislice tomography angiography used as diagnostic tool for UAV.[89] Whereas, echocardiography remains a useful and reliable method for the diagnosis of a UAV. Mookadam et al.[10] systemically reviewed nine articles with 60 pediatric cases (age <15 years) of UAV. He reported the most common presentation of UAV was congestive heart failure due to congenital aortic stenosis, and the most common lesion was isolated aortic stenosis, reported in 19 cases (32%). Associated anomalies included 22 cases (37%) of aortic coarctation, 7 (12%) with VSD, 3 (5%) with PDA, and 3 (5%) with aortic aneurysm. The preoperative diagnosis of UAV was rare, and 33 cases (55%) of pediatric UAV were reported at autopsy or at the pathological examination of the surgically excised valves. UAV are usually stenotic at birth requiring aortic valve replacement in third decade of life. Many affected patients require intervention for severe stenosis in infancy or childhood. Others may remain hemodynamically stable for several years or decades before they require intervention for calcified stenosis or regurgitation. Treatment involves replacement of the aortic valve when the stenosis is severe enough. Although stenotic unicuspid valves are treated by valvotomy, regurgitant UAVs are commonly aortic valve replaced. Aortic valve repair, including bicuspidisation, can be performed with low risk and excellent operative results. Novaro et al.[2] conclude that patients with UAVs will present for cardiac surgery in their third decade of life.

CONCLUSION

UAV is a rare congenital anomaly of the aortic valve. This case demonstrates incidental diagnosis of UAV with moderate aortic stenosis in an infant who is asymptomatic and not accompanies any other congenital heart diseases. The surgical intervention had been deferred in this case and closely followed with echocardiography for aortic stenosis severity.

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Conflicts of interest

There are no conflicts of interest.