Previous studies revealed a number of acquired risk factors predisposing to acute deep vein-thrombosis (DVT). Unfortunately many of these clinical or epidemiologic studies were not proper designed, since they didn't include consecutive patients, used no or different types of objective endpoints or collected the data retrospectively. In a prospective trial we evaluated 307 consecutive out-patients with clinically suspected DVT by using ascending venography, which confirmed suspicion in 136 (44%). A history of prior thrombotic episodes as well as factors predisposing to DVT including advancing age, obesity, smoking habits, cancer, chronic lung and/or heart disease, immobilization, pregnancy, childbirth, chronic liver disease, systemic lupus erythematosus (SLE), nephrotic syndrome, varicose veins, fractures or trauma or chronic arteriopathies of the legs, diabetes mellitus (DM), recent surgery and estrogen therapy were recorded in all patients. The results of our comparison of these risk factors with the outcome of venography indicate clearly a significant difference (chi-square test) between patients with and without DVT for the following: -previous documented thromboembolism, cancer (p < 0.01); -chronic lung and/or heart disease, age > 65 years, immobilization (p < 0.05). The frequency of pregnancy, childbirth, nephrotic syndrome and chronic liver disease among our patients was too low for providing sufficiently narrow confidence limits. Surprisingly the presence of varicose veins will decrease the possibility of DVT (p < 0.01). In all patients (n=3) affected by SLE clinical suspicion was confirmed. Obesity, smoking habits, recent trauma or fracture or chronic artheriopathies of the legs, DM, recent surgery and estrogen therapy were not associated with an increased risk of thrombosis, since their presence in both groups was approximately the same.
A review of the risk of deep vein thrombosis in surgical and minimally invasive treatment of varicose veins