Murphy C O, Gott J P, Guyton R A
Department of Surgery, Emory University School of Medicine, Crawford Long Hospital, Atlanta, Georgia 30365-2225, USA.
Ann Thorac Surg. 1997 Jan;63(1):20-6; discussion 26-7. doi: 10.1016/s0003-4975(96)00767-9.
The coronary microvascular system is important in the regulation of myocardial perfusion. Preservation of microvascular reactivity may be important in those hearts undergoing ischemic storage for transplantation. Endothelium-dependent relaxation of right and left ventricular coronary microvessels was examined in a canine model of heart transplantation.
Canine hearts underwent topical cooling, antegrade arrest, and 3 hours' ischemic cold storage at 4 degrees C using crystalloid cardioplegia (n = 8), Roe's solution (n = 8), and University of Wisconsin solution (n = 8). All groups underwent 1 hour of reperfusion in an isolated heart circuit. Noninstrumented canines were used as controls (n = 10). Coronary microvessels (100 to 200 microns in diameter) were examined in a pressurized, no-flow state with video microscopic imaging and electronic dimension analysis.
Endothelium-dependent microvascular relaxation was examined in response to the receptor-dependent acetylcholine and to the receptor-independent calcium ionophore. Microvascular relaxation to acetylcholine in Roe's solution and University of Wisconsin solution was preserved (p = not significant) in the left ventricle, whereas crystalloid cardioplegia failed to preserve (p < 0.05) microvascular relaxation when compared with the control groups. Right ventricular microvascular relaxation was always (p < 0.05) less than left ventricular microvascular relaxation. Endothelium-independent microvascular relaxation to nitroprusside was similar to that in controls, indicating normal smooth muscle responsiveness.
Ischemic cold storage with Roe's solution and University of Wisconsin solution preserved microvascular relaxation in the left ventricle, whereas crystalloid cardioplegia failed to preserve microvascular relaxation. Right ventricular microvascular relaxation was impaired in all groups, but University of Wisconsin solution was superior to crystalloid cardioplegia and Roe's solution. This suggests that microvascular dysfunction may be partially responsible for right ventricular dysfunction after heart transplantation. The choice of preservation solution may be important in preservation of the microvascular endothelium.
冠状动脉微血管系统在心肌灌注调节中起重要作用。对于接受缺血保存以供移植的心脏，维持微血管反应性可能至关重要。在犬心脏移植模型中，研究了左右心室冠状动脉微血管的内皮依赖性舒张。
犬心脏采用晶体停搏液（n = 8）、Roe溶液（n = 8）和威斯康星大学溶液（n = 8）进行局部降温、顺行性停搏，并在4℃下进行3小时的缺血性冷保存。所有组在离体心脏回路中进行1小时的再灌注。未插管的犬用作对照（n = 10）。使用视频显微镜成像和电子尺寸分析，在加压无血流状态下检查直径为100至200微米的冠状动脉微血管。
检测了内皮依赖性微血管舒张对受体依赖性乙酰胆碱和受体非依赖性钙离子载体的反应。Roe溶液和威斯康星大学溶液组左心室内皮依赖性微血管对乙酰胆碱的舒张得以保留（p =无显著性差异），而与对照组相比，晶体停搏液未能保留（p < 0.05）微血管舒张。右心室微血管舒张始终（p < 0.05）小于左心室微血管舒张。硝普钠诱导的非内皮依赖性微血管舒张与对照组相似，表明平滑肌反应性正常。
Roe溶液和威斯康星大学溶液进行缺血性冷保存可保留左心室微血管舒张，而晶体停搏液未能保留微血管舒张。所有组右心室微血管舒张均受损，但威斯康星大学溶液优于晶体停搏液和Roe溶液。这表明微血管功能障碍可能是心脏移植后右心室功能障碍的部分原因。保存液的选择对于微血管内皮的保存可能很重要。
