COMPARISON OF IN-VIVO TISSUE TEMPERATURE PROFILE AND LESION GEOMETRY FOR RADIOFREQUENCY ABLATION WITH A SALINE-IRRIGATED ELECTRODE VERSUS TEMPERATURE CONTROL IN A CANINE THIGH MUSCLE PREPARATION-猫眼课题宝

DOI：

10.1161/01.cir.91.8.2264

发表时间：

1995-04-15

期刊：

CIRCULATION

影响因子：

37.8

通讯作者：

中科院分区：

医学1区

文献类型：

作者：

NAKAGAWA, H;YAMANASHI, WS;JACKMAN, WM

背景在射频消融过程中，只有靠近电极的一薄层组织被电流直接加热（电阻加热）。大多数的热损伤被认为是由表面层的热传导引起的。本研究的目的是确定是否可以通过用更高的射频功率在组织中产生更深的直接电阻加热来增加损伤深度，允许通过用盐水冲洗冷却消融电极来防止当电极-组织界面温度达到100 ℃时发生的阻抗上升。方法和结果在11只麻醉狗中，将大腿肌肉暴露并用肝素化的犬血（36 ℃至37 ℃）浸泡。将带有中心腔、带有6个灌注孔的5 mm头端电极和内部热敏电阻的7 F导管垂直于大腿肌肉放置，并保持10 g的恒定接触重量。在高恒定电压（66 V）下向145个部位（1）输送放射性电流，无需冲洗（CV组，n=31），（2）在可变电压（20至66 V），以将头端电极温度保持在80 ℃至90 ℃，无需冲洗（3）高CV（66 V）下，通过导管腔和消融电极以20 mL/min的速度进行生理盐水灌注（CV灌注组，n=75）。施加辐射电流60秒，但在阻抗上升大于或等于10欧姆的情况下立即终止。测量了所有三组（n=145）中3.5 mm和7.0 mm深度处的尖端电极温度和组织温度。在33例CV灌注组应用中，还使用单独的探头在电极-组织界面的中心（n=18）或边缘（n=15）测量温度。在所有31次CV组应用中，由于与98.8+/-2.1 ℃的电极温度相关的阻抗升高，射频能量输送提前终止（在11.6+/-4.8秒时）。所有39次温度控制应用均持续60秒，无阻抗升高，但必须将电压降至38.4+/-6.1 V，以避免温度>90 ℃（平均头端电极温度，84.5+/-1.4 ℃）。在CV灌注应用中，头端-电极温度不>48 ℃（平均值，38.4+/-5.1 ℃），电极-组织界面温度不>80 ℃（平均值，69.4+/-5.7 ℃）。在30 - 51秒时，在75次CV灌注组应用中的6次中，阻抗突然升高，伴有可听到的爆裂声，且无凝块，可能是由于蒸汽从表面下方释放。在CV和温度控制组应用中，3.5（62.1+/-15.1 ℃和67.9+/-7.5 ℃）和7.0 mm（40.3+/-5.3 ℃和48.3+/-4.8 ℃）深度处的温度始终低于电极温度。相反，在CV灌注组应用中，3.5 mm（94.7+/-9.1 ℃）深度和偶尔7.0 mm（65.1+/-9.7 ℃）深度处的组织温度始终超过电极和电极-组织界面温度。CV组应用中的病变尺寸最小（深度，4.7+/-0.6 mm;最大直径，9.8+/-0.8 mm;体积，135+/-33 mm（3）），在温度控制组应用中居中（深度，6.1+/-0.5 mm;最大直径，11.3+/-0.9 mm;体积，275+/-55 mm（3）），CV灌注组应用中最大（深度，9.9+/-1.1 mm;最大直径，14.3+/-1.5 mm;体积，700+/-217 mma; P

Background It is thought that only a thin layer of tissue adjacent to the electrode is heated directly by electrical current (resistive heating) during radiofrequency ablation. Most of the thermal injury is thought to result from conduction of heat from the surface layer. The purpose of this study was to determine whether lesion depth could be increased by producing direct resistive heating deeper in the tissue with higher radiofrequency power, allowed by cooling the ablation electrode with saline irrigation to prevent the rise in impedance that occurs when the electrode-tissue interface temperature reaches 100 degrees C.Methods and Results In 11 anesthetized dogs, the thigh muscle was exposed and bathed with heparinized canine blood (36 degrees C to 37 degrees C). A 7F catheter, with a central lumen, a 5-mm tip electrode with six irrigation holes, and an internal thermistor, was positioned perpendicular to the thigh muscle and held at a constant contact weight of 10 g. Radiofrequency current was delivered to 145 sites (1) at high constant voltage (66 V) without irrigation (CV group, n=31), (2) at variable voltage (20 to 66 V) to maintain tip-electrode temperature at 80 degrees C to 90 degrees C without irrigation (temperature-control group, n=39), and (3) at high CV (66 V) with saline irrigation through the catheter lumen and ablation electrode at 20 mL/min (CV irrigation group, n=75). Radiofrequency current was applied for 60 seconds but was terminated immediately in the event of an impedance rise greater than or equal to 10 Ohm. Tip-electrode temperature and tissue temperature at depths of 3.5 and 7.0 mm were measured in all three groups (n=145). In 33 CV irrigation group applications, temperature was also measured with a separate probe at the center (n=18) or edge (n=15) of the electrode-tissue interface. In all 31 CV group applications, radiofrequency energy delivery was terminated prematurely (at 11.6+/-4.8 seconds) owing to an impedance rise associated with an electrode temperature of 98.8+/-2.1 degrees C. All 39 temperature-control applications were delivered for 60 seconds without an impedance rise, but voltage had to be reduced to 38.4+/-6.1 V to avoid temperatures >90 degrees C (mean tip-electrode temperature, 84.5+/-1.4 degrees C). In CV irrigation applications, the tip-electrode temperature was not >48 degrees C (mean, 38.4+/-5.1 degrees C) and the electrode-tissue interface temperature was not >80 degrees C (mean, 69.4+/-5.7 degrees C). An abrupt impedance rise with an audible pop and without coagulum occurred in 6 of 75 CV irrigation group applications at 30 to 51 seconds, probably owing to release of steam from below the surface. In the CV and temperature-control group applications, the temperatures at depths of 3.5 (62.1+/-15.1 degrees C and 67.9+/-7.5 degrees C) and 7.0 mm (40.3+/-5.3 degrees C and 48.3+/-4.8 degrees C) were always lower than the electrode temperature. Conversely, in CV irrigation group applications, electrode and electrode-tissue interface temperatures were consistently exceeded by the tissue temperature at depths of 3.5 mm (94.7+/-9.1 degrees C) and occasionally 7.0 mm (65.1+/-9.7 degrees C). Lesion dimensions were smallest in CV group applications (depth, 4.7+/-0.6 mm; maximal diameter, 9.8+/-0.8 mm; volume, 135+/-33 mm(3)), intermediate in temperature-control group applications (depth, 6.1+/-0.5 mm; maximal diameter, 11.3+/-0.9 mm; volume, 275+/-55 mm(3)), and largest in CV irrigation group applications (depth, 9.9+/-1.1 mm; maximal diameter, 14.3+/-1.5 mm; volume, 700+/-217 mma; P

COMPARISON OF IN-VIVO TISSUE TEMPERATURE PROFILE AND LESION GEOMETRY FOR RADIOFREQUENCY ABLATION WITH A SALINE-IRRIGATED ELECTRODE VERSUS TEMPERATURE CONTROL IN A CANINE THIGH MUSCLE PREPARATION

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