Local metabolic, pathophysiological and histological changes in venous ulcers

Abstract

The pathogenesis of venous ulceration is not completely understood. The aim of this research was to measure and compare various parameters in ulcers caused by abnormalities in superficial venous (SU) versus deep venous flow (DU), to determine possible differences in their pathogenesis. Analysis of venous blood gases and levels of anaerobic metabolites from the ulcer site were measured in SU (n=8) and DU patients (n=8) and compared with control samples from the contralateral healthy limb. Histological examination via electron microscopy was also performed in tissue samples from the ulcer sites in SU (n=2) and DU (n=2) patients. The SU group had significantly lower values of partial oxygen pressure (pO2) and oxygen saturation (sO2), and significantly higher values of partial pressure of carbon dioxide, bicarbonate concentration and total carbon dioxide versus control samples. The DU group had significantly higher values of pO2 and sO2 versus controls. Elevated levels of pyruvate (P < 0.01) and lactate (P < 0.05) were found in DU ulcer blood samples taken after 30 min of passive standing (static shear), as compared with control blood samples. However, no significant histological differences between SU and DU samples could be distinguished via electron microscopy. Differences in levels of venous blood gases and anaerobic metabolites indicate a potential difference in the causation and development of superficial versus deep venous caused ulcers. This may have clinical significance for the diagnosis and treatment of these conditions.