We aimed to determine the incidence of and associated risk factors for endovenous heat-induced thrombosis (EHIT) after endovenous radiofrequency ablation (RFA).

We retrospectively reviewed the medical records of 82 patients with 97 great saphenous veins undergoing RFA from 2012 to 2014.

The incidence of EHIT was 10.3%. Class 1, 2, and 3 EHIT was found in 50%, 30%, and 20% of legs, respectively. No class 4 EHIT, deep vein thrombosis, or pulmonary emboli occurred. Univariate analysis revealed that the associated risk factors for EHIT were a vein diameter of >10 mm, operative time of >40 min, and Caprini score of >6. Multivariate analysis revealed that the independent risk factors associated with EHIT were a vein diameter of >10 mm and operative time of >40 min.

A vein diameter of >10 mm and operative time of >40 min might be predictive factors for EHIT following RFA.