Endovenous radiofrequency ablation has become an accepted mode of treatment for superficial venous reflux. In this study, we evaluated the incidence of endovenous heat-induced thrombosis (EHIT), its progression, and risk factors that may contribute to its formation.


This was a prospective study of all patients who underwent radiofrequency ablation of the great saphenous vein (GSV), accessory GSV, and small saphenous vein (SSV) from March 1, 2010, to September 30, 2011, from 12 of our affiliated vein centers in a primary vein practice. Demographic data, CEAP classification, previous history of deep venous thrombosis (DVT), body mass index, vein diameter, reflux time, catheter tip position, EHIT progression, number of stab phlebectomies, and Venous Clinical Severity Score of patients with EHIT were analyzed.


Of the 6707 treated limbs, 4906 (73%) had GSV, 145 (2%) had accessory GSV, and 1656 (25%) had SSV ablation. EHIT developed in 201 limbs of 194 patients for an overall incidence of 3%. A nonfatal pulmonary embolism occurred in two patients (0.03%). Patients who developed EHIT were slightly older than those without EHIT (median age, 59 vs 56 years). In patients with EHIT, 34.8% were men, but only 25% were men among those who had no EHIT (P = .002). GSV, accessory GSV, and SSV diameters were larger in EHIT patients (P < .001 for all). Reflux time and catheter tip distance from the saphenous junctions were similar in those with and without EHIT. EHIT resolution occurred in 2 to 4 weeks in most patients, but EHIT worsening occurred in nine (4.5%) that all resolved ≤4 weeks. In the EHIT patients, 68% had multiple concomitant phlebectomies compared with 39.4% of those without EHIT (P < .0001). DVT history made no difference for EHIT development (P = .065). All but two class 1 and one class 2 EHIT patients were managed with observation and aspirin due to DVT history and physician concern. The Venous Clinical Severity Score was obtained only in the last 70 EHIT cases. The mean score was 5.92 preoperatively and improved to 2.08 at the 1-month follow-up.


Large vein diameter, male sex, and multiple phlebectomies are risk factors for development of EHIT. We recommend that EHIT class 1 and 2 patients be managed with observation or antiplatelets, or both, but class 3 and 4 patients should be anticoagulated.