Coronary and endocardial fibroelastosis of the ventricles in the hypoplastic left and right heart syndromes

Abstract

In an autopsy material of 29 cases of the hypoplastic left heart syndrome coronary fibroelastosis was found in 1 case, endocardial fibroelastosis in 8 cases. Figures for 10 cases of the hypoplastic right heart syndrome were 6 cases of coronary fibroelastosis and 1 case of endocardial fibroelastosis. Age ranged from stillborn up to 11-1/2 months. Coronary and endocardial fibroelastosis seemed to be mutually exclusive localizations of congenital fibroelastosis since in our material they did not occur together in the same hearts. In hypoplastic right hearts coronary fibroelastosis was either restricted to the right coronary artery (right circumflex and posterior interventricular branch), or it was found also in the left coronary artery (anterior interventricular branch), with the most serve affections always being situated in the right one. In the only case of coronary fibroelastosis among the hypoplastic left hearts the condition was limited to the anterior interventricular branch of the left coronary artery which communicated with the hypoplastic left ventricle by a fistula. Coronary fibroelastosis was exclusively found in branches supplying the hypoplastic right ventricle and/or in a branch connected by a fistula to the hypoplastic left or right ventricle. Endocardial fibroelastosis was generally found in hypoplastic left ventricles with either no outflow or with severe outflow obstruction. A theory concerning the aetiology of both coronary and endocardial fibroelastosis of the hypoplastic ventricles is proposed. It is argued that development of fibroelastosis may in both localizations be caused or favoured by the coincidence of two factors: abnormal haemodynamic conditions and poor oxygenation of blood and tissues. Observations made in a reference material of 35 hypoplastic left and 24 hypoplastic right hearts were in accordance with this view.

Endocardial Fibroelastosis is Secondary to Hemodynamic Alterations in the Chick Embryonic Model of Hypoplastic Left Heart Syndrome

“…Increased periostin expression affects the proliferation, collagen synthesis, migration, and invasion of keloid fibroblasts under hypoxic conditions. This study tests the theory proposed by Essed and collaborators (Essed et al, 1975) linking abnormal hemodynamics, hypoxia, and increased fibrosis in a chick model of HLHS induced by left atrial ligation (LAL) (Sedmera et al, 1999). We observed well established EFE at later stages that was secondary to the hemodynamic alterations in this condition, possibly underlined by abnormal ventricular strains and myocardial hypoxia.…”

“…Primary EFE is not associated with other significant morphological or structural abnormalities of the heart. Secondary EFE is associated with various congenital heart diseases (Angelov et al, 1984), most notably hypoplastic left heart syndrome (HLHS) (Essed et al, 1975) and aortic stenosis or atresia (Achiron et al, 1988), but also maternal autoimmune diseases (Nield et al, 2002). Other developmental abnormalities in HLHS include underdevelopment of the left atrium and ventricle, deformed or very small mitral and aortic valves, and the right ventricle rather the left forming the apex of the heart (Bohlmeyer et al, 2003;Sedmera et al, 2005).…”

The Relation Between Right Ventricular Function and Left Ventricular Morphology in Hypoplastic Left Heart Syndrome: Angiographic and Pathological Studies

“…The myocardial damage seen in operative specimens might be caused by relative hypoperfusion of coronary arteries at the time of operation in MS cases with markedly thickened myocardium. Previous studies reported the marked endocardial fibroelastosis of the left ventricle in MS/AA, describing the elevation of LV end-diastolic pressure as its etiology [1,2,5,12]. We consider that such endocardial fibroelastosis of the left ventricle is caused not only by elevated LV end-diastolic pressure but also by relative myocardial ischemia as mentioned previously.…”

The significance of ventriculo-coronary arterial connections in the setting of pulmonary atresia with an intact ventricular septum

“…84 There tends, nonetheless, to be a mutually exclusive relationship between the presence of the connections and the absence of ventricular endocardial fibroelastosis. [85][86][87] Thus, in those hearts with ventriculocoronary arterial connections, right ventricular endocardial fibroelastosis, if present at all, tends to be mild, and patchy. If right ventricular endocardial fibroelastosis is dense and diffuse, it is most unlikely that significant ventriculo-coronary arterial connections will be present.…”

“…If right ventricular endocardial fibroelastosis is dense and diffuse, it is most unlikely that significant ventriculo-coronary arterial connections will be present. [85][86][87] Furthermore, it is likely that, in the hearts with the connections, mural hypertrophy will be severe, attenuating or obliterating the apical trabecular zone. 38,49 The infundibular component of the right ventricle may also be attenuated or absent, a finding we demonstrated more than three decades ago using the double-catheter technique 88 (Fig.…”