Ambardekar Amrut V, Hunter Kendall S, Babu Ashok N, Tuder Rubin M, Dodson R Blair, Lindenfeld JoAnn
From the Department of Medicine, Division of Cardiology (A.V.A.), Department of Bioengineering (K.S.H., R.B.D.), Department of Pediatrics, Division of Cardiology (K.S.H.), Department of Surgery, Division of Cardiothoracic Surgery (A.N.B.), Department of Medicine, Divisions of Pulmonary Sciences and Critical Care Medicine (R.M.T.), and Department of Surgery, Division of Pediatric Surgery (R.B.D.), University of Colorado, Aurora; and Vanderbilt Heart and Vascular Institute, Nashville, TN (J.L.).
Circ Heart Fail. 2015 Sep;8(5):944-52. doi: 10.1161/CIRCHEARTFAILURE.114.001955. Epub 2015 Jul 1.
The effects of nonpulsatile flow on the aorta are unknown. Our aim was to examine the structure of the aorta from patients with continuous-flow left ventricular assist devices (LVADs) and directly measure aortic wall composition and stiffness.
Age-matched aortic wall samples were collected from consecutive patients with heart failure (HF) at the time of transplantation and compared with nonfailing donor hearts. An unbiased stereological approach was used to quantify aortic morphometry and composition, and biomechanical testing was performed to determine the stress-strain relationship of the vessel. Data were obtained from 4 patients without a left ventricular assist device (HF group: mean age, 58.3±8.0 years), 7 patients with a continuous-flow LVAD (HF+LVAD group: mean, 57.7±5.6 years), and 3 nonfailing donors (mean, 53.3±12.9 years). Compared with HF, the aortic walls from HF+LVAD had an increase in wall thickness, collagen, and smooth muscle content accompanied by a reduction in elastin and mucinous ground-substance content. Stress-strain curves from the aortas revealed increased vessel stiffness in HF+LVAD compared with HF and nonfailing. The physiological modulus of the aorta progressively stiffened from 74.3±5.5 kPa in the nonfailing to 134.4±35.0 kPa in the HF to 201.7±36.4kPa in the HF+LVAD groups (P<0.001).
Among continuous-flow LVAD patients without aortic valve opening, there are changes in the structure and composition of the aorta as well as an increase in aortic wall stiffness compared with age-matched HF patients and nonfailing donors. Further studies examining the role of nonpulsatile blood flow on aortic function and the potential resultant systemic sequelae are needed.
非搏动性血流对主动脉的影响尚不清楚。我们的目的是研究接受连续流左心室辅助装置（LVAD）患者的主动脉结构，并直接测量主动脉壁成分和硬度。
在移植时从连续的心力衰竭（HF）患者中收集年龄匹配的主动脉壁样本，并与无心力衰竭的供体心脏进行比较。采用无偏倚的体视学方法量化主动脉形态和成分，并进行生物力学测试以确定血管的应力-应变关系。数据来自4例未使用左心室辅助装置的患者（HF组：平均年龄58.3±8.0岁）、7例使用连续流LVAD的患者（HF+LVAD组：平均年龄57.7±5.6岁）和3例无心力衰竭的供体（平均年龄53.3±12.9岁）。与HF组相比，HF+LVAD组的主动脉壁厚度、胶原蛋白和平滑肌含量增加，同时弹性蛋白和黏液性基质含量减少。主动脉的应力-应变曲线显示，与HF组和无心力衰竭组相比，HF+LVAD组的血管硬度增加。主动脉的生理模量从无心力衰竭组的74.3±5.5 kPa逐渐增加到HF组的134.4±35.0 kPa，再到HF+LVAD组的201.7±36.4 kPa（P<0.001）。
在没有主动脉瓣开放的连续流LVAD患者中，与年龄匹配的HF患者和无心力衰竭的供体相比，主动脉的结构和成分发生了变化，主动脉壁硬度增加。需要进一步研究来探讨非搏动性血流对主动脉功能的作用以及潜在的全身后遗症。
