title: Histological difference between pulsed wave laser and continuous wave laser in endovenous laser ablation.
abstract: BACKGROUND
  Endovenous laser ablation to saphenous veins has been popular as a minimally invasive treatment for chronic venous insufficiency. However, adverse effects after endovenous laser ablation using continuous wave laser still remain. Pulsed wave with enough short pulse duration and sufficiently long thermal relaxation time may avoid the excess energy delivery, which leads to the perforation of the vein wall.
  
  
  METHODS
  (1) Free radiation: Laser is radiated in blood for 10 s. (2) Endovenous laser ablation: Veins were filled with blood and placed in saline. Endovenous laser ablations were performed.
  
  
  RESULTS
  (1) There were clots on the fiber tips with continuous wave laser while no clots with pulsed wave laser. (2) In 980-nm continuous wave, four of 15 specimens had ulcers and 11 of 15 had perforation. In 1470-nm continuous wave with 120 J/cm of linear endovenous energy density, two of three presented ulcers and one of three showed perforation. In 1470-nm continuous wave with 60 J/cm of linear endovenous energy density, two of four had ulcers and two of four had perforation. In 1320-nm pulsed wave, there were neither ulcers nor perforation in the specimens.
  
  
  CONCLUSIONS
  While endovenous laser ablation using continuous wave results in perforation in many cases, pulsed wave does not lead to perforation.
authors.affiliation: The Department of Cardiovascular Surgery, Edogawa Hospital, Tokyo, Japan The Department of Cardiovascular Surgery, Juntendo University, Tokyo, Japan kansaku-ths@umin.ac.jp.
authors.forename: Rei
authors.initials: R
authors.lastname: Kansaku
authors.affiliation: The Department of Cardiovascular Surgery, Edogawa Hospital, Tokyo, Japan The Department of Cardiovascular Surgery, Juntendo University, Tokyo, Japan.
authors.forename: Naoki
authors.initials: N
authors.lastname: Sakakibara
authors.affiliation: The Department of Cardiovascular Surgery, Juntendo University, Tokyo, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Amano
authors.affiliation: The Department of Pathology, Edogawa Hospital, Tokyo, Japan.
authors.forename: Hisako
authors.initials: H
authors.lastname: Endo
authors.affiliation: The Department of Cardiovascular Surgery, Edogawa Hospital, Tokyo, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Shimabukuro
authors.affiliation: Shinagawa Heart Medical Clinic, Tokyo, Japan.
authors.forename: Michiaki
authors.initials: M
authors.lastname: Sueishi
mesh_terms: D016342:Angioplasty, Laser / Q000379:methods*; D002908:Chronic Disease; D057510:Endovascular Procedures / Q000379:methods*; D005260:Female; D006801:Humans; D007834:Lasers; D008297:Male; D012501:Saphenous Vein; D014689:Venous Insufficiency / Q000628:therapy*
keywords: Chronic venous disease; chronic venous insufficiency; endovenous laser treatment; endovenous thermal ablation; pathology/histology