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[Morphology of the hypoplastic left heart syndrome from the surgical perspective]
1Dĕtské kardiocentrum FN Motol, Praha.
Insights
Hypoplastic left heart syndrome (HLHS) involves complex heart malformations. This study details anatomical variations in HLHS, crucial for surgical and fetal interventions.
Area of Science:
- Cardiology
- Developmental Biology
- Pediatric Surgery
Context:
- Hypoplastic left heart syndrome (HLHS) is a critical congenital heart defect characterized by underdevelopment of the left heart structures.
- Understanding the spectrum of anatomical variations is vital for effective treatment strategies.
Purpose:
- To analyze the detailed anatomy of 61 hearts with HLHS.
- To correlate anatomical findings with potential surgical and fetal interventions.
Summary:
- The study reviewed 61 HLHS specimens, revealing diverse malformations including enlarged right heart chambers, restrictive foramen ovale in 23%, and small left ventricles (26.2% extreme hypoplasia).
- Common combinations included mitral stenosis with aortic atresia (36.1%) and mitral/aortic stenosis (32.8%). Dysplastic mitral valves and left ventricular endocardial fibroelastosis (39.3%) were frequent.
- Aorta was consistently hypoplastic (2-4 mm diameter), with coarctation in 16.4%. Persistent left superior vena cava was the most common associated lesion.
Impact:
- Findings provide critical anatomical insights for surgical planning, including Norwood procedures, and highlight challenges in extreme aortic hypoplasia.
- The study underscores the complexity of HLHS, informing future research into fetal surgical interventions and ventricular augmentation techniques.
Abstract:
Hypoplastic left heart syndrome (HLHS) is found in a wide spectrum of changes of the mitral valve, left ventricle and aorta. It represents a critical congenital heart disease with a small left ventricle and stenosis or atresia of the aortic and the mitral valve. The knowledge of a detailed anatomy of this lesion is necessary from the viewpoint of assessment of all possibilities of the surgical treatment, interventional cardiological procedures or foetal cardiac surgery. Sixty one hearts with HLHS from the collection of heart specimens with congenital heart malformations were reviewed. The existence of a wide spectrum of malformations of all heart structures was proved. In all the cases enlarged right atrium and right ventricle was found. In 23.0% of specimens foramen ovale was restrictive or closed. The left ventricle was small in all the hearts, extreme hypoplasia was observed in 26.2% in presence of a combination of the mitral and the aortic atresia. Most commonly, the combination of mitral stenosis with aortic atresia (36.1%) and combination of mitral and aortic stenosis (32.8%) were present. Mitral atresia with aortic stenosis was identified in 4.9% cases. The mitral valve was usually dysplastic with short and thick chordae and smaller annulus. In 39.3% of all hearts fibroelastosis of the left ventricular endocardium was present. In these cases moderate degree hypoplasia of the left ventricle in combination with mitral and aortic stenosis was often found (65.0%). All the aorta was hypoplastic starting from the aortic valve, across the ascendent part and aortic arch until the isthmus. Its diameter usually varied between 2 and 4 mm. Coarctation of the aorta was found in 16.4% hearts. Persistent left superior caval vein represented the most common associated heart lesion. From the surgical point of view, nearly in all reviewed hearts Norwood surgery, consisting in aortic reconstruction from aorta, main pulmonary artery and a patch from the pulmonary homograft could be performed. Reconstruction would be very difficult in presence of an extreme hypoplasia of the ascending aorta. Until present, possibilities to prevent the development of the left ventricular hypoplasia by a foetal surgical intervention or possibility of the surgical augmentation of the left ventricle by excision of a thick endocardium do not cross the horizons of theory.