[Risk of venous thromboembolism in the course of acute medical illness. Part 1: Basic research, clinical models, descriptive and analytic epidemiology].

PURPOSE: Some acute medical illnesses are associated with an increased risk of venous thromboembolism. This risk is difficult to assess in medical patients on account of the multiplicity of their pathologies, leading to potential interactions between numerous risk factors. CURRENT KNOWLEDGE AND KEY POINTS: A rational analysis of the risk of venous thrombosis in acute medical setting may be derived from pathogenic models and be based on elementary risk factors for venous thromboembolism classified as transient, permanent, major and intermediate factors. The systematic study of pathophysiological mechanisms in process, in each medical patient could guide the physician attitude toward still non-evaluated situations. FUTURE PROSPECTS AND PROJECTS: A synthesis of the last epidemiological and pathophysiological data is developed in the first part of this literature review, whereas the risk linked to specific situations in ambulatory, hospital or internal medicine settings will be described in the second part.