Tian G, Shen J, Su S, Sun J, Xiang B, Oriaku G I, Saunders J K, Salerno T A, Deslauriers R
Institute for Biodiagnostics, National Research Council of Canada, Winnipeg, Manitoba, Canada.
J Thorac Cardiovasc Surg. 1997 Jul;114(1):109-16. doi: 10.1016/s0022-5223(97)70123-5.
This study was done to determine whether retrograde delivery of cardioplegic solution provides uniform blood flow to the myocardium supplied by an occluded coronary artery and whether it maintains myocardial energy levels beyond the coronary occlusion.
Isolated pig hearts were used. A hydraulic occluder was placed at the origin of the left anterior descending coronary artery. The perfusion pressure for retrograde delivery of cardioplegic solution was controlled at 40 to 50 mm Hg. Magnetic resonance imaging and localized 31P magnetic resonance spectroscopy were used to assess myocardial perfusion and energy metabolism, respectively.
Magnetic resonance perfusion images (n = 7) showed that the perfusion defect that occurred during antegrade delivery of cardioplegic solution (as a result of the occlusion of the left anterior descending coronary artery) resolved during retrograde delivery of cardioplegic solution. Retrograde perfusion delivered similar amounts of flow to the jeopardized myocardium as it did to other areas of the myocardium. However, the distribution of cardioplegic solution by the retrograde route was heterogeneous (cloudlike) across both ventricular walls. 31P magnetic resonance spectra showed that the ischemic changes induced by occlusion of the left anterior descending artery during antegrade perfusion were greatly alleviated by retrograde perfusion; however, it took longer for retrograde cardioplegia (n = 7, 17.08 minutes) to restore the levels of inorganic phosphate/phosphocreatine relative to the effect of releasing the left anterior descending artery occluder during antegrade delivery of cardioplegic solution (n = 7, 5.3 minutes).
First, retrograde delivery of cardioplegic solution provides sufficient flow to the myocardium beyond a coronary occlusion to maintain near normal levels of energy metabolites, and second, the efficacy of the retrograde route of cardioplegic solution delivery (in terms of distribution of the solution and rate of myocardial energy recovery) is significantly lower than that of the antegrade route.
本研究旨在确定心脏停搏液逆行灌注是否能为闭塞冠状动脉所供血的心肌提供均匀血流，以及它能否在冠状动脉闭塞后维持心肌能量水平。
采用离体猪心。在左前降支冠状动脉起始处放置液压闭塞器。心脏停搏液逆行灌注的压力控制在40至50 mmHg。分别使用磁共振成像和局部31P磁共振波谱来评估心肌灌注和能量代谢。
磁共振灌注图像（n = 7）显示，心脏停搏液顺行灌注期间（由于左前降支冠状动脉闭塞）出现的灌注缺损在心脏停搏液逆行灌注时消失。逆行灌注为濒危心肌输送的血流量与心肌其他区域相似。然而，逆行途径的心脏停搏液在两个心室壁上的分布是不均匀的（呈云状）。31P磁共振波谱显示，顺行灌注期间左前降支闭塞引起的缺血性变化在逆行灌注时得到极大缓解；然而，相对于心脏停搏液顺行灌注时松开左前降支闭塞器的效果（n = 7，5.3分钟），逆行心脏停搏（n = 7，17.08分钟）恢复无机磷酸/磷酸肌酸水平所需的时间更长。
第一，心脏停搏液逆行灌注能为冠状动脉闭塞后的心肌提供足够血流，以维持能量代谢物接近正常水平；第二，心脏停搏液逆行灌注途径的疗效（在溶液分布和心肌能量恢复速率方面）明显低于顺行途径。
