Mucoid degeneration of the atrioventricular valve caused by cardiac lymphostasis: An experimental study in dogs.
We performed an experiment to examine the influence of cardiac lymph congestion on the cardiac valves in dogs. A total of 6 mongrel dogs underwent surgery to induce cardiac lymph congestion, and 6 other animals underwent sham operation. Two weeks after operation, the atrioventricular valves of the experimental animals were intensively stained by Alcian blue. The optical densities of the tricuspid valves measured by a microscopic photometer were 0.069 ± 0.033 in the proximal portion, 0.134 ± 0.030 in the middle portion, and 0.117 ± 0.023 in the peripheral portion. All corresponding values obtained from the sham-operated animals showed lower values of 0.048 ± 0.012, 0.046 ± 0.014 (p < 0.05), and 0.060 ± 0.028 (p < 0.01), respectively. Electron microscopic observation revealed dilatation of the lymphatic vessels in the experimental valves. The results suggest that cardiac lymph congestion causes accumulation of mucopolysaccharides in the valve.