Kim S Y, Hinkamp T J, Jacobs W R, Lichtenberg R C, Posniak H, Pifarré R
Department of Thoracic and Cardiovascular Surgery, Loyola University Medical Center, Maywood, Illinois 60153.
Ann Thorac Surg. 1995 Apr;59(4):981-9. doi: 10.1016/0003-4975(95)00068-v.
This study compared aortic input impedance characteristics between patients with aortic interposition Dacron grafts placed for traumatic aortic injury and normal age-matched control subjects. All subjects were examined at rest and after treadmill exercise. Magnetic resonance imaging was conducted to rule out anatomic (stenosis) effects. Exercise increased characteristic impedance (ie, reduced aortic distensibility) by 29% and decreased total systemic arterial compliance by 21% in the patient group, whereas the normal control group showed insignificant change in these variables after exercise. Peripheral pressure wave reflection was reduced substantially with exercise (27%) in the control group, with much less reduction observed in the patient group. These abnormal vascular hemodynamics were associated with significantly high cardiac energetic costs in the patient group. A plausible explanation for the observed differences lies in the exaggerated vascular impedance mismatch between compliant aorta and inelastic graft, when cardiac output increases dramatically.
本研究比较了因创伤性主动脉损伤而植入涤纶人工血管的患者与年龄匹配的正常对照受试者之间的主动脉输入阻抗特征。所有受试者均在静息状态和跑步机运动后接受检查。进行磁共振成像以排除解剖学（狭窄）影响。运动使患者组的特征阻抗（即主动脉扩张性降低）增加了29%，全身动脉总顺应性降低了21%，而正常对照组在运动后这些变量的变化不显著。对照组运动后外周压力波反射大幅降低（27%），而患者组降低幅度小得多。这些异常的血管血流动力学与患者组显著较高的心脏能量消耗相关。观察到的差异的一个合理原因在于，当心输出量急剧增加时，顺应性主动脉与无弹性人工血管之间的血管阻抗失配加剧。
