Longitudinal growth of the autologous vessels above and below the Gore-Tex graft after the extracardiac conduit Fontan procedure.

OBJECTIVE: Reflecting excellent mid-term outcomes, extracardiac conduit Fontan procedure (ECFP) using Gore-Tex tube graft has been performed with increasing frequency in patients with functional single ventricle. Nevertheless, due to the lack of growth potential of the artificial conduit, the status of the venous pathway along with somatic growth is a continuing concern. In this study, we evaluated the longitudinal growth of the autologous vessels above and below the Gore-Tex graft used in the ECFP. METHODS: This study included 34 patients who had completed cardiac catheterisations at 1 month and 5.1 years after the ECFP. The average age, weight and height at the ECFP were 3.8+/-2.5 years (1.8-12.7 years), 12.7+/-4.6 kg (7.4-33.0 kg) and 92.9+/-16.1cm (72.5-153.5 cm), respectively. We measured the vertical lengths of three different parts angiographically: the length between the confluence point of the innominate vein and the anastomotic site of the conduit to the pulmonary artery (SVC-C), the conduit vertical length (C) and the length between the confluence point of the hepatic vein and the conduit's anastomotic site to the inferior vena cava (IVC-C). RESULTS: We have not observed stenosis or thrombus formation in the conduit or distortion of the conduit or pulmonary artery in any of the cases. No intervention or re-operation related to the extracardiac conduit was required, and laminar flow through the conduit was maintained with efficient Fontan haemodynamics. At 5.1 years after the ECFP, the average weight and height gain were 10.3+/-4.4 kg and 28.5+/-1.9 cm, respectively. The length of SVC-C, C and IVC-C were significantly increased as 124+/-15%, 106+/-7% and 132+/-24%, respectively, compared to the lengths at 1 month after the ECFP. The degree of increase in SVC-C and IVC-C was significantly larger than that in C. CONCLUSIONS: Along with the patient's somatic growth, longitudinal growth of the autologous vessels above and below the Gore-Tex graft was demonstrated to compensate for the lack of growth potential of the artificial graft.

Capillarization and venularization of hepatic sinusoids in porcine serum-induced rat liver fibrosis: a mechanism to maintain liver blood flow.

The processes of capillarization and venularization of sinusoids after porcine serum-induced rat liver fibrosis were studied by light and electron microscopy. Accompanying the development of fibrosis in the walls of central veins, most of the sinusoidal outlets collapsed, resulting in the formation of hepatic limiting plates around central veins. A few remaining sinusoids underwent capillarization (the development of a basal lamina and the defenestration of the sinusoidal endothelial cell), followed by venularization (the transformation into venules of sinusoids, characterized by the enlargement of the diameters with the lumina being lined with several endothelial cells, which lose fenestrae and develop a basal lamina). These newly formed venules served to maintain blood flow from sinusoids into central veins and thus have been designated the "outlet venules." Diameters of these venules could reach about 25 microns. They were classified into two types: (a) the septal outlet venules, which developed inside the septa; and (b) the angular outlet venules, which drained blood directly from the parenchyma into the fibrotic central veins at the angles between two septa. Associated with venularization, perisinusoidal stellate cells (fat-storing cells or Ito cells) differentiated to myofibroblasts.