Klar E, Kraus T, Bleyl J, Newman W H, Bowman H F, Hofmann W J, Kummer R, Bredt M, Herfarth C
Department of Surgery, University of Heidelberg, Heidelberg, Germany.
Microvasc Res. 1999 Sep;58(2):156-66. doi: 10.1006/mvre.1999.2166.
Hepatic microcirculation is a main determinant of reperfusion injury and graft quality in liver transplantation. Methods available for the quantification of hepatic microcirculation are indirect, are invasive, or preclude postoperative application. The aim of this study was the validation of thermodiffusion in a new modification allowing long-term use in the clinical setting. In six pigs Doppler flowmeters were positioned around the hepatic artery and portal vein for the measurement of total liver blood flow. Liver perfusion was quantified by thermodiffusion and compared to H(2) clearance as an established technique under baseline conditions, during different degrees of portal venous obstruction and during occlusion of the hepatic artery. Thermodiffusion measurements were recorded for five days postoperatively followed by histological evaluation of the hepatic puncture site. Perfusion data obtained by thermodiffusion were significantly correlated to H(2) clearance (r = 0.94, P < 0. 001) and to liver blood flow (r = 0.9, P < 0.05). The agreement between thermodiffusion and H(2) clearance was excellent (mean difference -2.1 ml/100 g/min; limits of agreement -12.5 and 8.3 ml/100 g/min). Occlusion of the portal vein or hepatic artery was immediately detected by thermodiffusion, indicating a decrease of perfusion by 64 +/- 7% or 27 +/- 5% of baseline, respectively. Perfusion values at baseline and during vascular occlusion were reproducible during the entire observation period. Histological changes of the liver tissue adjacent to the thermodiffusion probes were minute and did not influence long-term measurements. In vivo validation proved that enhanced thermodiffusion is a minimally invasive technique for the continuous, real-time quantification of hepatic microcirculation. Changes in liver perfusion can be safely detected over several days postoperatively. The implication for liver transplantation has led to the clinical application of thermodiffusion.
肝微循环是肝移植中再灌注损伤和移植物质量的主要决定因素。现有的用于量化肝微循环的方法是间接的、有创的，或者不能用于术后。本研究的目的是验证一种新改良的热扩散法，使其能够在临床环境中长期使用。在6头猪身上，将多普勒流量计放置在肝动脉和门静脉周围，用于测量肝脏总血流量。通过热扩散法对肝脏灌注进行量化，并与作为一种成熟技术的氢清除率在基线条件下、不同程度的门静脉阻塞期间以及肝动脉闭塞期间进行比较。术后记录热扩散测量值5天，随后对肝穿刺部位进行组织学评估。通过热扩散获得的灌注数据与氢清除率显著相关（r = 0.94，P < 0.001），与肝脏血流量显著相关（r = 0.9，P < 0.05）。热扩散法与氢清除率之间的一致性非常好（平均差异 -2.1 ml/100 g/min；一致性界限为 -12.5 和 8.3 ml/100 g/min）。热扩散法能立即检测到门静脉或肝动脉的闭塞，分别表明灌注减少至基线的64±7%或27±5%。在整个观察期内，基线和血管闭塞期间的灌注值是可重复的。热扩散探头附近肝组织的组织学变化微小，不影响长期测量。体内验证证明，改良后的热扩散法是一种微创技术，可用于连续、实时量化肝微循环。术后数天内可安全检测肝脏灌注的变化。这一结果对肝移植具有重要意义，促使热扩散法在临床上得到应用。
