title: Myocardial coagulation by intraoperative Nd:YAG laser ablation and its dependence on blood perfusion.
abstract: To investigate whether the efficacy of intraoperative laser ablation therapy is affected by myocardial blood perfusion, we irradiated 11 canine hearts through the epicardium with a Nd:YAG laser (10, 20, and 30 J/mm2) using air as the medium. Compared coagulated myocardial depth, width, and volume obtained in the red beating heart was compared with those in the white nonbeating heart infused with 0 degrees C saline (cardioplegic model) via the coronary artery. Histologically, the macro- and microscopical findings were very similar. At each level of energy, the width and volume of red myocardium coagulated were significantly larger than those of white myocardium (P < 0.01). At 30 J/mm2, the depth of coagulation of red myocardium was significantly larger than that of white myocardium (P < 0.01). The coagulated volume of the white myocardium was about 60% of that of the red myocardium. Nd:YAG laser energy was absorbed by blood (red color = hemoglobin), and more energy was transferred in the higher temperature myocardium. During intraoperative Nd:YAG laser ablation, the presence of blood perfusion in cardiac tissue is thought to be an important factor affecting safe irradiation.
authors.affiliation: Department of Surgery, Kanazawa University, School of Medicine, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Ohtake
authors.forename: T
authors.initials: T
authors.lastname: Misaki
authors.forename: G
authors.initials: G
authors.lastname: Watanabe
authors.forename: K
authors.initials: K
authors.lastname: Mukai
authors.forename: Y
authors.initials: Y
authors.lastname: Matsunaga
authors.forename: M
authors.initials: M
authors.lastname: Tsubota
authors.forename: M
authors.initials: M
authors.lastname: Kawasuji
authors.forename: Y
authors.initials: Y
authors.lastname: Watanabe
mesh_terms: D000818:Animals; D006328:Cardiac Catheterization; D006348:Cardiac Surgical Procedures / Q000379:methods; D003326:Coronary Circulation; D004285:Dogs; D017075:Laser Coagulation; D009206:Myocardium / Q000473:pathology*