Background and Aims: Varicose veins of the lower extremities are the common clinical manifestations of peripheral venous diseases, which can be caused by variety of diseases such as venous reflux diseases, venous reflux disorders of the lower extremities, and venous malformations. The treatment principles of varicose veins caused by different etiologies are also different. Misdiagnosis and mistreatment of varicose veins of the lower extremities often occur in clinical practice, so it is very important to determine the pathogeny of varicose veins. At present, venography of the lower extremity is still the gold standard for the diagnosis of venous diseases of the lower extremity, which can provide a complete image of the lower extremity venous system, and provide a reliable basis for the clear diagnosis and selection of the appropriate treatment scheme. The purpose of this study was to summarize the results of anterograde venography of deep vein of lower extremity in Changzhou, Jiangsu Province, and to evaluate the significance of venography, and to analyze the main etiologies of varicose vein in this region.  
Methods: From June 2013 to March 2019, 3 012 patients with varicose veins of the lower extremities (3 420 limbs) who were admitted to the Department of Vascular Surgery of the Third Affiliated Hospital of Suzhou University underwent anterograde venography with digital subtraction angiography (DSA). The morphology and patency of the deep veins from the ankle of the affected limb to segment in the pelvic cavity, as well as the reflow of the contrast material while the patient was performing the Valsalva maneuver were observed. Then, the etiologies of varicose vein of the patients were analyzed and classified. 
Results: In the 3 420 limbs, there were 1 395 limbs with primary deep venous valve insufficiency (40.79%), 1 052 limbs with simple superficial varicose veins (30.76%), 569 limbs with iliac vein compression syndrome (16.64 %), 328 limbs with post-thrombotic syndrome (9.59%), and 76 limbs (2.22%) with other pathogenies that included malformation of double femoral veins, popliteal venous aneurysm, deep venous aneurysm, Klippel-Trenaunay syndrome, Budd-Chiari syndrome and pelvic tumor.
Conclusion: The lower extremity varicose veins in patients in Changzhou region is mainly caused by deep venous insufficiency, simple superficial venous valve insufficiency and iliac vein compression. The proper treatment scheme for lower extremity varicose veins is based on the identification of pathogeny. Deep venography of lower extremities is a reliable method for distinguishing the etiologies of lower extremity varicose veins, which can determine the uncommon diseases such as popliteal venous aneurysm and Budd-Chiari syndrome, and thereby effectively avoid misdiagnosis and mistreatment. So, it is of great application value in peripheral venous diseases and can be used as a routine examination for peripheral venous diseases.