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6215894 
Journal Article 
309 Decreased myocardial capillary density in failing functionally univentricular heart (FUVH): a morphometric study 
De Montpreville, V; Houyel, L; Rucker-Martin, C; Serraf, A; To, NT 
2010 
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Background End-stage ventricular dysfunction is the most common cause of mortality in adults with FUVH. The physiopathology of this condition remains unclear. End-stage dilated as well as hypertrophic cardiomyopathies experience reduced capillary density. In FUVH physiology, volume overload leads to ventricular dilatation, followed by myocardial hypertrophy. We therefore hypothesize that FUVH also demonstrate a reduced capillary density. Methods Average capillary density was measured in 13 post-mortem human adult hearts: 5 failing FUVH and 8 controls. Hearts were preserved in 10% formalin. Free wall left ventricular longitudinal and transversal tissue specimens were harvested below the level of mitral valve papillary muscles. A morphometric study was realized after immunohistochemical staining of factor VIII. Capillary surface area was quantified by optical density on 50 different samples per patient. The capillary density was calculated: (capillary surface area) / (total ventricular surface area) (x100%) using Image J software. Results were expressed as mean ± sd. Results Among the 13 hearts, 6 allowed a correct interpretation of the capillary density: 3 FUVH (2 tricuspid atresia, 1 double-inlet left ventricle, all with end-stage ventricular dysfunction) and 3 controls (congenital heart disease with normal left ventricular function : 2 atrial septal defects with Eisenmenger syndrome, 1 tetralogy of Fallot with pulmonary atresia). There was no significant difference in arterial oxygen saturation between the 2 groups (71±1% in FUVH vs 85±0,8% in controls). Myocardial capillary density was significantly decreased in FUVH compared to controls (3.58±1.23% vs 7.69±3.29%, p<0.0001). Conclusion Myocardial capillary density is decreased in end-stage failing functionally univentricular hearts. Yet, further studies with a larger amount of patients are needed to assert the responsibility of the decreased capillary density for the ventricular dysfunction.