Aoyama Hiroshi, Nakagawa Hiroshi, Pitha Jan V, Khammar George S, Chandrasekaran Krishnaswamy, Matsudaira Kagari, Yagi Tetsuo, Yokoyama Katsuaki, Lazzara Ralph, Jackman Warren M
Cardiac Arrhythmia Research Institute and Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA.
J Cardiovasc Electrophysiol. 2005 Nov;16(11):1218-26. doi: 10.1111/j.1540-8167.2005.50126.x.
A canine model was used to compare cryoablation and radiofrequency ablation (RFA) within the coronary sinus (CS) in the ability to create a transmural CS myocardial (Trans-CSM) lesion and risk of coronary artery stenosis.
After CS and left circumflex (LCx) coronary angiography, an intravascular ultrasound (IVUS) probe was placed in LCx in 29 dogs. An irrigated RFA catheter (8 dogs) or N(2)O cryoablation catheter (21 dogs) was inserted into the CS and positioned within 2 mm of LCx, confirmed by IVUS. RF (30-50W) was applied for 60 seconds at 10 CS sites. Cryoablation (-75 degrees C) was performed with one (n = 7) or two (n = 14) 4-minute applications. Dogs were sacrificed at 1 week (8 RFA and 13 cryoablation) or 3 months (8 cryoablation).
During RFA, IVUS showed wall thickening and LCx narrowing in 9 of 10 sites. Angiography at 5-minute post-RFA identified LCx narrowing (25-90%) at 6 of 10 sites and 25-75% narrowing at 4 of 9 sites at 1-week post-RFA. During cryoablation, IVUS showed reversible ice ball compression of LCx, and no LCx narrowing by angiography at 5 minutes, 1 week, or 3 months. Histology showed Trans-CSM lesion at 10 of 10 RFA sites and 20 of 21 cryoablation sites. RFA produced LCx medial necrosis at 7 of 10 sites, involving 20-50%(median 32.5%) of LCx circumference with loss of intima at 5 of 7 sites. Single and twice 4-minute cryoablation produced LCx medial necrosis at 2 of 7 and 8 of 14 sites (5-40%, median 25% circumference). Intima was preserved at 1 week (13/13) with minor proliferation (without narrowing) at 2 of 8 sites at 3 months.
Cryoablation in CS within 2 mm of LCx produces Trans-CSM lesions similar to RFA with lower risk of LCx stenosis than RFA.
采用犬类模型比较冠状动脉窦（CS）内冷冻消融和射频消融（RFA）产生透壁性CS心肌（Trans-CSM）损伤的能力以及冠状动脉狭窄的风险。
对29只犬进行CS和左旋支（LCx）冠状动脉造影后，将血管内超声（IVUS）探头置于LCx。通过IVUS确认，将灌注式RFA导管（8只犬）或N₂O冷冻消融导管（21只犬）插入CS并置于距LCx 2 mm范围内。在CS的10个部位施加射频（30 - 50W）60秒。冷冻消融（-75℃）采用一次（n = 7）或两次（n = 14）4分钟的应用。犬在1周（8只RFA和13只冷冻消融）或3个月（8只冷冻消融）时处死。
在RFA期间，IVUS显示10个部位中的9个部位出现管壁增厚和LCx狭窄。RFA后5分钟的血管造影显示，10个部位中的6个部位在RFA后1周出现LCx狭窄（25% - 90%），9个部位中的4个部位出现25% - 75%的狭窄。在冷冻消融期间，IVUS显示LCx出现可逆性冰球压迫，在5分钟、1周或3个月时血管造影未显示LCx狭窄。组织学显示，10个RFA部位中的10个以及21个冷冻消融部位中的20个出现Trans-CSM损伤。RFA在10个部位中的7个部位导致LCx中层坏死，累及LCx周长的20% - 50%（中位数32.5%），7个部位中的5个部位内膜缺失。单次和两次4分钟的冷冻消融分别在7个部位中的2个和14个部位中的8个部位导致LCx中层坏死（5% - 40%，中位数25%周长）。1周时内膜保存完好（13/13），3个月时8个部位中的2个部位有轻微增殖（无狭窄）。
在距LCx 2 mm范围内的CS内进行冷冻消融产生的Trans-CSM损伤与RFA相似，但LCx狭窄风险低于RFA。
