Estudo comparativo do anel valvar mitral e do ventrículo esquerdo na cardiomiopatia dilatada

Abstract

P M A, Mioto B M, Chabelmann R C, Oliveira S A -Estudo comparativo do anel valvar mitral e do ventrículo esquerdo na cardiomiopatia dilatada. Material e Métodos: Analisaram-se 68 corações humanos adultos, fixados, sendo 48 portadores de CMD de etiologia isquêmica ou idiopática, e 20 corações sem cardiopatia. Obteve-se imagens digitalizadas do perímetro do anel mitral, inserção da cúspide anterior e posterior e da porção fibrosa e muscular. Obteve-se também o perímetro interno do VE, distância do septo ao músculo papilar anterior e posterior, distância entre os músculos papilares, e extensão do septo interventricular.Resultados: A análise dos resultados demonstrou proporcionalidade, tanto da porção fibrosa (r 2 = 0.98), quanto da porção muscular (r 2 = 0.99) do anel em relação ao grau de dilatação da valva mitral. A regressão linear revelou que o perímetro de inserção das cúspides anterior (r 2 = 0.96) e posterior (r 2 =0.98) também guardam relação de proporcionalidade. Observou-se que a dilatação do VE ocorre de forma global e esférica em seus segmentos. Não se observou relação de proporcionalidade entre o grau de dilatação do anel mitral e do VE.Conclusão: Ao contrário do que se pensava, na CMD de etiologia isquêmica ou idiopática, a dilatação do anel mitral ocorre de forma proporcional e não apenas na sua porção posterior. Não é o grau de dilatação do VE que determina o grau de dilatação do anel mitral pois eles ocorrem de forma independente. Estas observações abrem novas perspectivas para as técnicas de correção da insuficiência valvar mitral na CMD.

New contribution to the tudy of ventricular remodeling and valve rings in dilated cardiomyopathy: anatomical and histological evaluation

“…From a macroscopic point of view, it was noted that there dilatation in both ventricles of the idDCM group, albeit with distinct morphology, since the expansion of the RVR accompanies the expansion of the equatorial and basal ventricular segments, contrary to what happens in LVR which presents no significant expansion compared to the control group, although there was dilation of equatorial and basal segments at left. In relation to LVR, these findings confirm the results of Juliani [ 22 ] and Hueb et al [ 2 , 3 ] , who claim to not be the degree of left ventricular dilation that determines the degree of dilation of the mitral ring, since they occur independently. This statement has always been a matter of controversy in the literature.…”

“…Ventricular remodeling characterized by both right and left morphogeometrical changes, provides vicious cycle of functional deterioration, since the heart loses its original anatomical conformation, which is critical to its efficiency. In this context, the valve insufficiency caused primarily by expansion of the atrioventricular rings is of paramount importance [ 1 ] , but despite this relevant fact, the rings expansion mechanism is not completely understood [ 2 - 4 ] .…”

“…The anatomical concept that the fibrous skeleton of the heart does not dilate has been refuted [ 2 , 3 , 18 ] , and its enlargement has been proved in cases of severe heart failure due to dilated cardiomyopathy of ischemic (iscDCM) or nonchagasic idiopathic (idDCM) etiologies [ 2 , 3 ] ; however, it does not exist in the literature comparative histological study of right and left atrioventricular rings in cases of idDCM in light of this new concept. At the same time, available knowledge about the role played by ECM in terms of control and regulation of this process is still scarce so that there is broad field of research being done in this area.…”

Cirurgia da insuficiência mitral no tratamento da insuficiência cardíaca avançada

“…The LV dilation almost always stretches the mitral annulus, but contrary to expectations, the degree of dilation of the LV and annulus may worsen somewhat independently from one another [13]. In dilated annulus, the physiological systolic annular contraction is compromised and added to the restriction on systolic excursion of the leaflets, culminates in FMI.…”

“…Besides the aforementioned, it is worth noting the morphological study of Hueb et al [13] in 2001, which changed the paradigm that the mitral annular dilatation spared the implantation of the anterior leaflet. The authors demonstrated that this portion of the mitral annulus is also dilated, although to a lesser degree.…”