Abstract

Endovenous treatment is increasingly supplanting open surgery for the treatment of varicose veins. Among emerging endovenous techniques, radiofrequency ablation (RFA) with a ClosureFast catheter is popular in Korea. The objective of this study was to evaluate and compare the efficacy and patient-reported outcomes of RFA of varicose veins. This is a retrospective study of a prospectively registered database of patients who underwent RFA for varicose veins from 2012 to 2013 in St. Marys Hospital in Seoul. Korea. Efficient ClosureFast RFA catheters (Medtronic, San Jose, CA, USA) were used. The techniques used for RFA of varicose veins were performed according to the manufacturers recommendations. Duplex scans and venous clinical severity scores (VCSSs) were used to document treatment outcome and patient symptoms before and after the procedures. Treatment outcomes were estimated before the procedure and 3 months, 6 months, and 12 months after the procedure. Outcomes were analyzed by paired t test, chi-square test, or Fishers exact test as well as by logistical regression. A total of 117 patients were evaluated for 183 consecutive RFA procedures (183 limbs). The initial technical success was 97.3% (178/183). The estimated mean VCSS changed over time from 4.0 ± 1.67 at preprocedure to 0.6 ± 1.05, 0.5 ± 1.02, and 0.6 ± 1.14 at 3 months, 6 months, and 12 months after the procedure, respectively. The improved VCSS was maintained 1 year after the procedure (p < 0.001). Recanalization of the saphenous vein was detected in 20 limbs at the 1-year follow up. The treatment failure group also exhibited a significant decline in the VCSS between preprocedure and 12 months (4.8 ± 1.76 vs. 1.8 ± 2.04, p < 0.001). Specifically, in the treatment failure group, 65% of limbs with episodic recanalization (13/20) were reoccluded or recanalized without venous reflux at the 1-year follow up. In this study, RFA of varicose veins had an initial success rate of 97.7% and a significantly improved patient VCSS at 1 year. Patients with episodic recanalization of the saphenous vein also exhibited an improved VCSS with favorable duplex findings at 1 year.

Abstract

In this work we develop a model of catheter ablation based on electromagnetic and thermal equations. This model allows the computation of the space and time evolution of temperature in the surroundings of the ablation zone. This result is relevant, as excessive temperature values may cause stream pops or esophageal ulcers. The resulting system of equations is solved using a Chebyshev spectral collocation method. Special attention is paid to the effect of blood perfusion and electrical conductivity, as there is no consensus in the literature concerning the modeling of these terms. In order to obtain the conditions that give rise to safer ablations, a parametric study is performed, where the effect of discharge time, discharge voltage and size of the electrode in the temperature distribution is analysed.