Evidence for microvascular thrombosis obtained by intravital fluorescence videomicroscopy.

A pattern of enlarged capillaries densely packed with red cells and not filled by the intravital dye Na-fluorescein for 10-20 min is described. Probably it corresponds to microvascular thrombosis. Alternative explanations like prolonged stasis appear unlikely. Up to now the pattern has been detected in severe chronic venous incompetence, collagen vascular disease and essential thrombocytosis.