Virchow's triad revisited: blood constituents.

An update of Virchow's triad for thrombogenesis can be considered by reference to abnormalities in the endothelium/endocardium ('abnormal vessel wall'), abnormalities of haemorhelogy and turbulence at bifurcations,atheroma at vessel wall ('abnormal bloodflow') and abnormalities in platelet as well as the coagulation and fibrinolytic pathways ('abnormal blood constituents'). The constituents of the blood are many and varied, but soluble coagulation factors (such as fibrinogen and tissue factor) and cells (such as platelets)are clearly important. Clearly, 'a continuum exists between health, 'statistically' increased haemostatic abnormalities in prothrombotic or hypercoagulable states and 'overtly' increased clotting in acute thrombosis.Thus, the patients with the highest levels of the markers appear to be the highest risk of disease progression,and if so, a panel of 'high risk' blood constituent indices (platelet and coagulation markers) may potentially give a composite score of risk, and may be a useful tool in predicting subjects at highest risk. Further longitudinal studies are clearly required. There is no doubt that Virchow would be impressed on how his classical triad has expanded to encompass the wide range of pathophysiological processes leading to thrombogenesis.