Hypoplastic Left Heart Syndrome With Left Ventricular Myocardial Sinusoids: Echocardiographic and Angiographic Findings in the First Neonate Surviving the Norwood I and II Procedure
Hypoplastic left heart syndrome (HLHS) encompasses a broad spectrum of congenital cardiac anomalies. It is characterized by underdevelopment of the left heart with significant hypoplasia of the left ventricle, including atresia, stenosis, or hypoplasia of the aortic or mitral valve, or both valves, and hypoplasia of the ascending aorta and aortic arch.1
A 25-year-old woman gave birth to her first child in the 40th week of gestation via caesarean delivery because of a pathological cardiotocogram. The neonate was transferred to the pediatric intensive care unit. Although the chest x-ray was unsuspicious on the first day of life (Figure 1A), the ECG exhibited ST elevation in left precordial leads indicating myocardial damage (Figure 1B), an unusual finding even in HLHS. Echocardiography confirmed the already prenatally diagnosed HLHS with aortic atresia and severe mitral hypoplasia (Figure 2A; online-only Data Supplement Movie I). The most interesting and critical finding was the presence of several marked myocardial sinusoids in the thickened left ventricular myocardium (Figure 2B and 2C; online-only Data Supplement Movies II and III). To clarify the anatomy, cardiac catheterization and angiography were performed. HLHS with aortic atresia and an extreme hypoplastic mitral valve with trivial incompetence and a small left ventricle with suprasystemic blood pressure were confirmed (Figure 3A; online-only Data Supplement Movie IV). The defect within the restrictive atrial septum was dilated by using a 4-mm cutting balloon and subsequently a 6-mm high pressure balloon. Selective left ventricular angiography demonstrated mycocardial sinusoids draining from the cavity through the hypertrophic myocardium to the left coronary artery (LCA), producing a retrograde flow in the LCA whereby an antegrade flow was present in the right coronary artery (Figure 3A, 3B, and 3C; online-only Data Supplement Movies IV and V). After discussing the complex cardiac situation, we chose a palliative approach toward total cavopulmonary connection (TCPC), and a modified Norwood I operation was performed (Figure 3D). Initially, we observed a stable postoperative course for about a week. Deteriorating clinical status initiated cardiac recatheterization, which revealed a mild gradient of 5 mm Hg in the distal aortic arch. This region was dilated with 8- and 10-mm balloons. Figure 4 demonstrates the distal aortic lesion before (A), during (B) and after (C) the dilatation. The clinical condition stabilized during the subsequent weeks, and the patient could be discharged. He remained well in follow-up exams and underwent a successful Norwood II procedure at the age of 9 months. The myocardial sinusoids are still present.
Ventriculo-coronary arterial communications are rare congenital heart defects that have traditionally been explained on the basis of abnormal persistence of such communications found in the normal developing heart.2 The incidence of coronary abnormalities in HLHS is higher in patients with mitral hypoplasia and aortic atresia. The pathological coronary morphology in our patient with marked left ventricular myocardial sinusoids draining into the LCA is a rare condition and has only been described in postmortem studies or in a few neonates who died shortly after birth because of lack of therapeutic concepts.3,4 To the best of our knowledge, this is the first report on a neonate surviving HLHS with this coronary pathology after palliative cardiac surgery.
The online-only Data Supplement, consisting of 5 movies, can be found with this article at http://circ.ahajournals.org/cgi/content/full/117/e319/DCI.
Dr Bertram and Dr Hitz contributed equally to this work.