Travis Adam R, Giridharan Guruprasad A, Pantalos George M, Dowling Robert D, Prabhu Sumanth D, Slaughter Mark S, Sobieski Mike, Undar Akif, Farrar David J, Koenig Steven C
Cardiovascular Innovation Institute, University of Louisville, Louisville, Ky 40202, USA.
J Thorac Cardiovasc Surg. 2007 Feb;133(2):517-24. doi: 10.1016/j.jtcvs.2006.09.057.
We sought to investigate differences in indices of pulsatility between patients with normal ventricular function and patients with heart failure studied at the time of implantation with continuous-flow or pulsatile-flow left ventricular assist devices.
Eight patients with normal ventricular function and 22 patients with heart failure were studied. A high-fidelity aortic and left ventricular pressure catheter was inserted retrograde through the aortic valve into the left ventricle, and transit-time flow probes were placed on the aorta and device outflow graft. Hemodynamic waveforms were recorded at native heart rate before cardiopulmonary bypass and over a range of device flow rates controlled by adjusting beat rate or rpm. These data were used to calculate vascular input impedance and 2 indices of vascular pulsatility: energy-equivalent pressure and surplus hemodynamic energy.
At low support levels, pulsatile support restored surplus hemodynamic energy to within 2.5% of normal values, whereas continuous support diminished surplus energy by more than 93%. At high support levels, pulsatile support augmented surplus energy by 49% over normal values, whereas continuous support further diminished surplus energy by 97%. Pulsatile support diminished vascular impedance from baseline failure values, whereas continuous support increased impedance. Vascular impedances at baseline for patients undergoing pulsatile and continuous support and during pulsatile support revealed normal vascular compliance, whereas impedance during continuous support indicated a loss of compliance (or "stiffening") of the vasculature.
These results suggest that selection of device type and flow rate can influence vascular pulsatility and input impedance, which might affect clinical outcomes.
我们试图研究在植入连续流或搏动流左心室辅助装置时，正常心室功能患者与心力衰竭患者之间搏动指数的差异。
对8例正常心室功能患者和22例心力衰竭患者进行了研究。通过主动脉瓣逆行插入一根高保真主动脉和左心室压力导管至左心室，并将渡越时间血流探头置于主动脉和装置流出道移植物上。在体外循环前以患者自身心率记录血流动力学波形，并在通过调整心率或转速控制的一系列装置流速下进行记录。这些数据用于计算血管输入阻抗和两个血管搏动指数：能量等效压力和剩余血流动力学能量。
在低支持水平下，搏动支持将剩余血流动力学能量恢复至正常值的2.5%以内，而持续支持使剩余能量减少超过93%。在高支持水平下，搏动支持使剩余能量比正常值增加49%，而持续支持使剩余能量进一步减少97%。搏动支持使血管阻抗从基线衰竭值降低，而持续支持使阻抗增加。接受搏动支持和持续支持的患者在基线时以及搏动支持期间的血管阻抗显示血管顺应性正常，而持续支持期间的阻抗表明血管系统顺应性丧失（或“硬化”）。
这些结果表明，装置类型和流速的选择可影响血管搏动性和输入阻抗，这可能会影响临床结局。
