Atresia of the aortic valve is usually associated with hypoplasia of the mitral valve and left ventricle. In less than 7% of patients, a ventricular septal defect may be associated with aortic atresia, when the left ventricle and mitral valve are normal-sized, due to the presence of an outflow for the left ventricle through the ventricular septal defect. We present the multi-modality imaging findings of an adolescent girl who presented with breathlessness and was later found to have aortic valvar atresia with a normal-sized left ventricle.
Case report
An adolescent girl (16 years old) presented with dyspnoea on exertion (New York Heart Association functional class II) and exertional palpitations for over 5 years, for which she had gradually restricted her activities. Her perinatal and family history was unremarkable. She also had loss of appetite. On examination, she was undernourished (body mass index 13.3 kg/m2). There was no cyanosis or clubbing. She had decreased oxygen saturation (∼84% on room air) in all four extremities with normal blood pressure and pulse. Her cardiovascular examination revealed a diffuse apical impulse, loud and palpable P2, grade III left parasternal heave, and grade III/IV early diastolic murmur in the left 3rd intercostal space parasternal area. Other systems were normal. Her chest radiograph showed situs solitus with the apex on the left side and mild cardiomegaly. The pulmonary arterial shadow was enlarged (Supplementary Figure 1A). Her electrocardiogram showed right ventricular hypertrophy and right axis deviation (Supplementary Figure 1B).
Transthoracic echocardiography showed normal systemic and pulmonary venous connections with concordant atrio-ventricular and ventriculo-arterial connections. The pulmonary trunk (MPA) right and left pulmonary arteries were dilated with mild pulmonary regurgitation (Figure 1A). The right ventricle was hypertrophied with mild to moderate tricuspid regurgitation and right ventricular systolic pressure of around 120 mmHg. A large peri-membranous ventricular septal defect [asterisk (*) in Figure 1B] was noted with a small additional apical muscular ventricular septal defect and patent arterial duct (Video 1,2). The ascending aorta was not properly visualised in parasternal views. The ascending aorta and arch seen in the suprasternal views were hypoplastic [asterisk (*) in Figure 1C], but the evaluation was suboptimal. Retrograde flow was seen in the ascending aorta (Figure 1D; Video 3).
Her cardiac CT showed aortic valvar atresia with a hypoplastic ascending aorta (maximum diameter of 5.4 mm). The mitral valve was normal with a normal-sized left ventricle (Figure 2A). The two coronary arteries (white arrows in Figure 2A, 2B) were seen arising in the anticipated locations from the hypoplastic ascending aorta (yellow arrow in Figure 2C). There was an eccentric discrete constriction in the aortic arch at the insertion of arterial duct giving a pseudo-coarctation like appearance (Figure 2C). Her cardiac catheterisation revealed supra-systemic pulmonary pressures. The aortogram revealed a large patent arterial duct, dilated pulmonary trunk, and retrograde filling of the hypoplastic ascending aorta (Fig. 3a,b; Video 4). She was started on vasodilators to reduce pulmonary arterial pressures (Sildenafil 20 mg 8 hourly) and counselled to maintain hydration and avoid heavy exertion. Her dyspnoea has reduced and she is currently awaiting surgery.
Figure 1. Transthoracic echocardiographic images showing the dilated MPA and RPA (1a), a large VSD (indicated by * in 1b). The ascending aorta was hypoplastic (* in 1c) with retrograde flow (1d). MPA: the pulmonary trunk, RPA: right pulmonary artery; DA = descending aorta; RVOT = right ventricular outflow tract; RVSP = right ventricular systolic pressure; RV = right ventricle; LV = left ventricle.
Figure 2. Cardiac CT (2a, 2b—multiplanar reformatted images) showing the aortic valvar atresia (white arrows in 2 a) with a normal mitral valve and left ventricle. The coronary arteries (white dashed arrows in 2b) were seen arising in the anticipated locations from the small aortic root. Volume rendered image showing the hypoplastic ascending aorta (yellow arrow) with a large patent arterial duct and eccentric constriction opposite to the duct.
Figure 3. Images from catheter angiography showing the patent arterial duct (PDA) and dilated pulmonary trunk (MPA) in 3A and delayed phase images showing retrograde filling of hypoplastic ascending aorta (AA) and coronary arteries in 3B.
Discussion
During development, normal blood flow stimulates the normal development of structures in both systemic and pulmonary circulations. Reference Rudolph, Heymann and Spitznas1,Reference Bardo, Frankel, Applegate, Murphy and Saneto2 When an atretic or critically stenotic aortic valve impairs the normal antegrade outflow from the left ventricle into systemic circulation, the ascending aorta and coronary arteries receive low-pressure diastolic retrograde flow via the patent arterial duct and aortic arch. This results in hypoplastic aortic root and ascending aorta. This is usually seen in association with other left-sided abnormalities such as mitral stenosis or atresia, as a part of the hypoplastic left heart syndrome. Reference Noonan and Nadas3 However, the presence of a normal mitral valve and a ventricular septal defect differentiates the morphology in our patient from a conventionally described ‘hypoplastic left heart syndrome’. The presence of a ventricular septal defect provides an effective outflow to the left ventricle, thus, allowing adequate growth of the mitral apparatus and left ventricle, which would otherwise be hypoplastic. The classically described ‘hypoplastic left heart syndrome’ can be interpreted as representing an acquired disease of fetal life, with the severity of the lesion reflecting the stage in fetal life at which the left ventricle stopped growing. Reference Anderson, Crucean and Spicer4 In these children, blood flow through the arch and the descending aorta remains adequate through the arterial duct, and hence, attains their normal diameter.
Aortic atresia with hypoplastic ascending aorta in a patient with normal size of the left ventricle is extremely rare and reported only in early childhood. Reference Roberts, Perry, Chandra, Meyers, Shapiro and Scott5–Reference Jagia, Sharma, Gupta and Guleria7 Initial presentation in adolescence is extremely rare. Reference Esmaeilzadeh, Naderi and Tabaei8 This pattern as seen with our patient has also been misinterpreted as common arterial trunk with origin of the coronary arteries from the brachiocephalic artery. Reference Li, Li and Chen9 A normal left ventricle size in these patients gives the opportunity for a biventricular repair, in contrast to patients with hypoplastic left ventricle. Two surgical approaches have been proposed, one with early palliative surgery in neonatal period followed by complete correction in a later stage, and second with primary biventricular repair during neonatal life. Reference Bernhard, Poirier and LaFarge10,Reference Freedom, Culham and Rowe11,Reference Perry, Scott, Shapiro, Chandra and Roberts12,Reference Thiene, Gallucci, Macartney, Torso, Pellegrino and Anderson13 Excellent survival has been reported with primary neonatal biventricular repair, as surgery in early stage prevents development of intractable congestive heart failure and pulmonary vascular obstructive disease. Reference Perry, Scott, Shapiro, Chandra and Roberts12,Reference Nathan, Rimmer and del Nido14
Conclusion
In conclusion, aortic atresia with a normal-sized left ventricle is an extremely rare anomaly, usually presenting in early childhood. Comprehensive imaging assessment helps in adequate characterisation of the defect and helps in surgical planning.
Acknowledgements
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Competing interests
None.
