Hypoplastic left heart syndrome: a review

Abstract

Background: Hypoplastic left heart syndrome (HLHS) is an etiologically multifactorial congenital heart disease affecting one in 5,000 newborns. Thirty years ago there were no treatment options for this pathology and the natural course of the disease led to death, usually within the first weeks of life. Recently surgical palliative techniques have been developed allowing for a five-year survival in more than half the cases.

Materials and methods: We reviewed literature available on HLHS, specifically its anatomy, embryology and pathophysiology, and treatment. The Pubmed and ClinicalKey databases were searched using the key words hypoplastic left heart syndrome, foetal aortic valvuloplasty, foetal septoplasty, Norwood procedure, bidirectional Glenn procedure, Fontan procedure, hybrid procedure. The relevant literature was reviewed and included in the article. We reported a case from Children's Clinical University Hospital, Riga, to illustrate treatment tactics in Latvia.

Results: There are three possible directions for therapy in newborns with HLHS: orthotopic heart transplantation, staged surgical palliation and palliative non-surgical treatment or comfort care. Another treatment mode - foetal therapy - has arisen. Staged palliation and full Fontan circulation is a temporary solution, however, the only means for survival until heart transplantation. Fifty to 70% of patients who have gone through all three stages of palliation live to the age of five years.

Conclusions: The superior mode of treatment is not yet clear and the management must be based on each individual case, the experience of each clinic, as well as the financial aspects and will of the patient's parents.

Keywords: Fontan procedure; Norwood procedure; balloon valvuloplasty; bidirectional Glenn procedure; hybrid procedure; hypoplastic left heart syndrome.

Fig. 1.

Anatomy of hypoplastic left heart syndrome. Ao – transverse aorta; DA – ductus arteriosus; LA – left atrium; LV – left ventricle; RA – right atrium; RV – right ventricle; TP – truncus pulmonalis; VCI – vena cava inferior; VCS – vena cava superior; # – hypoplastic ascending aorta; * – foramen ovale

Fig. 2.

Norwood procedure. Neo – neoarta; LA – left atrium; LV – left ventricle; PA – pulmonary artery; RA – right atrium; RV – right ventricle; SA – subclavian artery; VCI – vena cava inferior; VCS – vena cava superior; # – modified Blalock-Taussig shunt; * – foramen ovale

Fig. 3.

Hybrid procedure. Ao – transverse aorta; DA – stent in ductus arteriosus; LA – left atrium; LV – left ventricle; RA – right atrium; RV – right ventricle; TP – truncus pulmonalis; VCI – vena cava inferior; VCS – vena cava superior; # – pulmonary artery banding; * – balloon in foramen ovale

Fig. 4.

Bidirectional Glenn procedure. Neo – neoarta; LA – left atrium; LV – left ventricle; PA – pulmonary artery; RA – right atrium; RV – right ventricle; VCI – vena cava inferior; VCS – vena cava superior; * – foramen ovale

Fig. 5.

Fontan procedure. ExC – extra-cardiac conduit; Neo – neoarta; LA – left atrium; LV – left ventricle; PA – pulmonary artery; RA – right atrium; RV – right ventricle; VCI – vena cava inferior; VCS – vena cava superior; * – foramen ovale

Fig. 6.

Echocardiography image. Apical four-chamber view. The left atrium (LA) is much smaller than the right atrium (RA). Rudimentary left ventricle (LV), aortic and mitral valve atresia. The right ventricle (RV) occupies the cardiac apex

Fig. 7.

Echocardiography image. Suprasternal long-axis view. Preductal coarctation of the aorta (Co Ao). Retrograde flow from stented ductus to transverse arch (Ao arch)