Clinical and Pathoanatomical Characteristics of Hypoplastic Left Heart Syndrome a Clinical Case

Abstract

Hypoplastic left heart syndrome (HLHS) is a common congenital heart defect, accounting for 4 to 16% of cases, and is one of the most prognostically unfavorable, involving single-­ventricle hemodynamics. HLHS involves hypoplasia of the left ventricle, often in combination with atresia and/or stenosis of the aortic and/or mitral valves, as well as hypoplasia of various parts of the aorta. Intrauterine reduction in blood flow to the left heart structures at early stages of fetal development subsequently leads to severe changes in cardiac structures, often not amenable to surgical correction. Objective. To study the clinical and morphological features of HLHS using a clinical case as an example. Materials and Methods. The patient was a child from the first pregnancy, which was complicated by anemia and first-­trimester preeclampsia. The defect was diagnosed prenatally at 23/24 weeks. At 39 weeks, labor was induced, and the infant was hospitalized in the intensive care unit with symptoms of cardiac and respiratory failure. On the 6th day of life, surgical treatment was performed — a Norwood operation, which is a single-­ventricle hemodynamic surgical correction of the defect. Despite intensive care measures, multiple organ failure progressed, leading to the development of disseminated intravascular coagulation (DIC) and subsequent death on the 10th day of life. Results. Autopsy, including staining of the myocardium with Masson’s trichrome and hematoxylin and eosin, showed pronounced plethora of the microcirculatory vessels with formation of erythrocyte thrombi. Pronounced perivascular edema and fraying of muscle fibers were detected. Fibroelastosis of the endocardium of the left ventricle was observed, characterized by pronounced sclerotic thickening due to significant proliferation of fibrous tissue, with the spread of connective tissue strands into the myocardium. Endocardial fibroelastosis is a component of HLHS and one of the determining factors in the outcome of cardiac surgery. Conclusion. The results of this work indicate the complexity of HLHS as a developmental defect, the severity of its clinical manifestations, and the limited prospects of currently existing surgical treatment methods. These patients may require heart transplantation in the first days of life. A potential alternative to early postnatal heart transplantation may be the development of methods for intrauterine correction of the existing developmental defect.