The aim of the study is to make a validation of Caprini score in patients undergoing varicose veins surgery, especially endovascular procedures (endovascular laser treatment - EVLT, radiofrequency ablation - RFA, ultrasound-guided foam sclerotherapy - USFS) and to identify patients with elevated risk of postoperative venous thromboembolism (VTE) who will benefit from prophylactic anticoagulation.

A prospective cohort study based on the platform of Ongoing Registry of Treatment of Chronic Venous Diseases (NCT03035747). The study will enrol adult patients undergoing any kind of varicose veins surgery with and without any prophylaxis. The patients should be examined for venous thromboembolic complications during 2-4 weeks after the procedure with mandatory duplex ultrasound.

The study will provide following information:

• the rate of asymptomatic DVT after varicose veins surgery
• the rate of symptomatic VTE after varicose veins surgery
• the rate of thermal-induced thrombosis (EHIT) after endovenous thermal ablation
• the ability of Caprini scores to predict VTE after varicose veins surgery
• identification of patients with high risk of VTE who will benefit from prophylaxis, especially with anticoagulation

Inclusion Criteria:

• age over 18 years
• any kind of varicose vein surgery
• follow up for 4 weeks after the procedure
• examination for VTE at 2-4 weeks after the procedure, including duplex ultrasound

Exclusion Criteria:

- lost for follow-up during 4 weeks

Any patient with varicose veins that undergoing any kind of varicose vein surgery.