Morphology of Hypoplastic leftHeart Syndrome from the Surgical Point of View

Overview

Hypoplastic left heart syndrome (HLHS) is found in a wide spectrum of changes of the mitralvalve, left ventricle and aorta. It represents a critical congenital heart disease with a small leftventricle and stenosis or atresia of the aortic and the mitral valve. The knowledge of a detailedanatomy of this lesion is necessary from the viewpoint of assessment of all possibilities of thesurgical treatment, interventional cardiological procedures or foetal cardiac surgery.Sixty one hearts with HLHS from the collection of heart specimens with congenital heart malfor-mations were reviewed. The existence of a wide spectrum of malformations of all heart structureswas proved. In all the cases enlarged right atrium and right ventricle was found. In 23,0% ofspecimens 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 theaortic atresia. Most commonly, the combination of mitral stenosis with aortic atresia (36,1%) andcombination of mitral and aortic stenosis (32,8%) were present. Mitral atresia with aortic stenosiswas identified in 4,9% cases. The mitral valve was usually dysplastic with short and thick chordaeand smaller annulus. In 39,3% of all hearts fibroelastosis of the left ventricular endocardium waspresent. In these cases moderate degree hypoplasia of the left ventricle in combination withmitral and aortic stenosis was often found (65,0%). All the aorta was hypoplastic starting from theaortic valve, across the ascendent part and aortic arch untill the isthmus. Its diameter usuallyvaried between 2 and 4 mm. Coarctation of the aorta was found in 16,4% hearts. Persistent leftsuperior caval vein represented the most common associated heart lesion.From the surgical point of view, nearly in all reviewed hearts Norwood surgery, consisting inaortic reconstruction from aorta, main pulmonary artery and a patch from the pulmonary homo-graft could be performed. Reconstruction would be very difficult in presence of an extremehypoplasia of the ascending aorta. Untill present, possibilities to prevent the development of theleft 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.

Key words:
circulation –⁠ congenital heart disease –⁠ hypoplastic left heart syndrome -⁠ morphology –cardiac surgery