Peltz Matthias, Cobert Michael L, Rosenbaum David H, West LaShondra M, Jessen Michael E
Department of Cardiovascular and Thoracic Surgery, University of Texas Southwestern Medical Center at Dallas, TX 75390-8879, USA.
Surgery. 2008 Aug;144(2):225-32. doi: 10.1016/j.surg.2008.05.002.
Optimal parameters for machine perfusion preservation of hearts prior to transplantation have not been determined. We sought to define regional myocardial perfusion characteristics of a machine perfusion device over a range of conditions in a large animal model.
Dog hearts were connected to a perfusion device (LifeCradle, Organ Transport Systems, Inc, Frisco, TX) and cold perfused at differing flow rates (1) at initial device startup and (2) over the storage interval. Myocardial perfusion was determined by entrapment of colored microspheres. Myocardial oxygen consumption (MVO(2)) was estimated from inflow and outflow oxygen differences. Intra-myocardial lactate was determined by (1)H magnetic resonance spectroscopy.
MVO(2) and tissue perfusion increased up to flows of 15 mL/100 g/min, and the ratio of epicardial:endocardial perfusion remained near 1:1. Perfusion at lower flow rates and when low rates were applied during startup resulted in decreased capillary flow and greater non-nutrient flow. Increased tissue perfusion correlated with lower myocardial lactate accumulation but greater edema.
Myocardial perfusion is influenced by flow rates during device startup and during the preservation interval. Relative declines in nutrient flow at low flow rates may reflect greater aortic insufficiency. These factors may need to be considered in clinical transplant protocols using machine perfusion.
心脏移植前机器灌注保存的最佳参数尚未确定。我们试图在大型动物模型的一系列条件下定义一种机器灌注装置的局部心肌灌注特征。
将犬心脏连接到灌注装置（LifeCradle，器官运输系统公司，弗里斯科，德克萨斯州），并在不同流速下进行冷灌注：（1）在装置初始启动时，（2）在保存期间。通过捕获彩色微球来测定心肌灌注。根据流入和流出的氧差异估计心肌耗氧量（MVO₂）。通过¹H磁共振波谱法测定心肌内乳酸含量。
MVO₂和组织灌注在流速达到15 mL/100 g/min时增加，心外膜：心内膜灌注比保持在接近1:1。较低流速灌注以及在启动时应用低流速会导致毛细血管血流量减少和非营养性血流量增加。组织灌注增加与心肌乳酸积累减少相关，但水肿更严重。
心肌灌注受装置启动期间和保存期间流速的影响。低流速下营养性血流量的相对下降可能反映了更严重的主动脉瓣关闭不全。在使用机器灌注的临床移植方案中可能需要考虑这些因素。
