Koenig Steven C, Pantalos George M, Gillars Kevin J, Ewert Dan L, Litwak Kenneth N, Etoch Steven W
Jewish Hospital Heart and Lung Institute, Department of Surgery, University of Louisville, Kentucky 40202, USA.
ASAIO J. 2004 Jan-Feb;50(1):15-24. doi: 10.1097/01.mat.0000104816.50277.eb.
This study investigated the hemodynamic and left ventricular (LV) pressure-volume loop responses to continuous versus pulsatile assist techniques at 50% and 100% bypass flow rates during simulated ventricular pathophysiologic states (normal, failing, recovery) with Starling response behavior in an adult mock circulation. The rationale for this approach was the desire to conduct a preliminary investigation in a well controlled environment that cannot be as easily produced in an animal model or clinical setting. Continuous and pulsatile flow ventricular assist devices (VADs) were connected to ventricular apical and aortic root return cannulae. The mock circulation was instrumented with a pressure-volume conductance catheter for simultaneous measurement of aortic root pressure and LV pressure and volume; a left atrial pressure catheter; a distal aortic pressure catheter; and aortic root, aortic distal, VAD output, and coronary flow probes. Filling pressures (mean left atrial and LV end diastolic) were reduced with each assist technique; continuous assist reduced filling pressures by 50% more than pulsatile. This reduction, however, was at the expense of a higher mean distal aortic pressure and lower diastolic to systolic coronary artery flow ratio. At full bypass flow (100%) for both assist devices, there was a pronounced effect on hemodynamic parameters, whereas the lesser bypass flow (50%) had only a slight influence. Hemodynamic responses to continuous and pulsatile assist during simulated heart failure differed from normal and recovery states. These findings suggest the potential for differences in endocardial perfusion between assist techniques that may warrant further investigation in an in vivo model, the need for controlling the amount of bypass flow, and the importance in considering the choice of in vivo model.
本研究在成人模拟循环中，于模拟心室病理生理状态（正常、衰竭、恢复）且具有斯塔林反应行为的情况下，研究了在50%和100%旁路流速时，连续与搏动性辅助技术对血流动力学及左心室（LV）压力 - 容积环的反应。采用这种方法的基本原理是希望在一个易于控制的环境中进行初步研究，而这在动物模型或临床环境中不容易实现。连续流和搏动流心室辅助装置（VAD）连接到心室心尖和主动脉根部回流插管。模拟循环配备了压力 - 容积电导导管，用于同时测量主动脉根部压力、LV压力和容积；左心房压力导管；远端主动脉压力导管；以及主动脉根部、主动脉远端、VAD输出和冠状动脉流量探头。每种辅助技术都降低了充盈压（平均左心房和LV舒张末期）；连续辅助比搏动辅助多降低50%的充盈压。然而，这种降低是以更高的平均远端主动脉压力和更低的舒张期与收缩期冠状动脉血流比为代价的。对于两种辅助装置，在全旁路流量（100%）时，对血流动力学参数有显著影响，而较小的旁路流量（50%）只有轻微影响。在模拟心力衰竭期间，连续和搏动性辅助的血流动力学反应与正常和恢复状态不同。这些发现表明，辅助技术之间的心内膜灌注可能存在差异，这可能值得在体内模型中进一步研究，控制旁路流量的必要性，以及考虑体内模型选择的重要性。
