Histological characterization of the inferior vena cava in cases of duplicated inferior vena cava.

Abstract

Duplicated inferior vena cava (DIVC) is a congenital anomaly where the inferior vena cava (IVC) is present on either side of the abdominal aorta. Previous studies have noted smaller IVC widths in DIVC cases, but detailed structural characteristics remain unclear. This study aimed to characterize the histological structure of the IVC in DIVC and normal cases. Histological analysis was performed on the IVC just below the liver (IVC-Liver), the IVC at the 4th lumbar vertebra level (IVC-L4), and the external iliac vein (EIV) from donated cadavers. The tissues underwent HE staining and immunohistochemistry to detect elastin and alpha smooth muscle actin, with the cross-sectional area of vessel lumina and immunopositive area calculated. The study found that the combined cross-sectional areas of the right and left IVC-L4 in DIVC cases were smaller than the single IVC-L4 area in normal cases. Histologically, DIVC cases showed a significantly decreased ratio of elastin immunopositive areas, compared to normal cases. This reduction in cross-sectional areas and elastin ratio suggests that IVCs in DIVC cases hold less blood volume and have weaker contractility by elastic fibers after dilation, potentially leading to disrupted blood circulation in the lower body.