Objective: To describe the histopathological changes of the vein wall caused by bipolar radiofrequency-induced thermotherapy (RFITT), and to examine influence of power and application time on the histopathological changes.
Material and methods: Twenty vein specimens atraumatically extracted near the saphenofemoral junction were treated by RFITT ex vivo. RFITT was applied with fixed (2 seconds) and varied (up to an impedance of 400 Ω) application time and increasing power (5, 10, 15, 20, 25 W). Specimens were processed histologically.
Results: RFITT induced coagulation of collagen bundles, shrinking of muscles, splitting and necrosis of the vein wall. Circumferential necrosis of intima and media was reached by a power of 20-25 W and an application time up to an impedance of 400 Ω. Only heterogeneous necrosis of intima and media in parts of the vessel was reached by lower power with long application time.
Conclusion: A homogeneous necrosis of the circumferential vein wall needs high power and sufficient application time.