Thrombogenesis and endothelial damage/dysfunction in peripheral artery disease. Relationship to ethnicity and disease severity.

Peripheral artery disease (PAD) and intermittent claudication are common in men aged over 55 years. Once the diagnosis has been made, very few patients suffer from a deterioration of the disease. Those that do deteriorate tend to do so due to thrombosis of an affected artery. It is apparent that the disruption in the vessel wall accounts for some of the cause of the thrombosis but blood constituents also play a role. We hypothesized that levels of soluble P-selectin (sP-sel, a marker of platelet activation), von Willebrand factor (vWf, an index of endothelial damage/dysfunction), tissue factor (TF, a coagulation protein involved in the 'extrinsic' coagulation pathway) and fibrinogen would be abnormally elevated in relation to disease severity and correlated with each other, and related to ethnicity, in a multiethnic population of patients with PAD. To test this hypothesis, we studied 234 patients (80% white, 7% Indo-Asian, 13% Afro-Caribbean) with confirmed PAD [ankle brachial pressure index (ABPI)< or =0.8] and 50 healthy controls. All of the indices studied were increased in patients over controls (p<0.05). None of the indices of the hypercoagulable state were significantly different between the three ethnic groups studied. Patients with ischaemic rest pain were shown to have higher levels of plasma fibrinogen (p<0.001) although none of the other prothrombotic markers were increased in this group. Furthermore, fibrinogen was higher in cases whose ABPI was below the median (<0.52) when compared to those less severely affected, with an inverse correlation between fibrinogen and ABPI (Spearman, r=-0.178, p=0.009). In conclusion, we found a prothrombotic state in patients with PAD with increased levels of markers of endothelial damage/dysfunction, platelet activation and thrombosis, which may contribute to the pathogenesis of this condition. However, disease severity was only related to plasma fibrinogen levels.