Segura Ana M, Gregoric Igor, Radovancevic Rajko, Demirozu Zumrut T, Buja L Maximilian, Frazier O H
(a)Departments of Cardiovascular Pathology Research , Texas Heart Institute, Houston.
J Heart Lung Transplant. 2013 Nov;32(11):1096-100. doi: 10.1016/j.healun.2013.07.007. Epub 2013 Aug 19.
Continuous-flow left ventricular assist devices (LVADs) provide durable, reliable, energy-efficient long-term support. However, the biologic effects of continuous flow are not completely known. Therefore, we examined aortic wall morphology in patients with heart failure before and after prolonged circulatory support with a continuous-flow LVAD.
After applying a partial aortic occlusion vascular clamp in the lower half of the ascending aorta, we removed samples of aortic wall tissue and then attached the outflow graft of the pump. Samples were obtained from 11 patients (9 men and 2 women, mean age 65 ± 7 years) with severe heart failure at the time of LVAD implantation. We obtained matched specimens at explantation after heart transplantation (n = 5) or autopsy (n = 6). These specimens were removed from the distal ascending aorta, remote from the aortic anastomotic site. Tissue sections were stained with hematoxylin and eosin, Movat's pentachrome and Masson's trichrome. Smooth muscle actin immunohistochemistry was performed on all sections. To evaluate the morphology of the aortic wall media, we quantitatively graded tissue sections for medial thickness, medial degenerative changes, smooth muscle cell (SMC) disorientation and depletion, elastic fiber fragmentation and depletion, medial fibrosis and atherosclerotic changes.
The mean duration of support was 140 ± 136 days (range 87 to 580 days). The histologic evaluation and comparison of specimens obtained before and after LVAD support showed significantly increased foci of medial degeneration, SMC depletion, elastic fiber fragmentation, medial fibrosis and atherosclerotic changes after LVAD support. Mean medial thickness was not significantly different after LVAD support. We observed similar changes between samples obtained at transplantation and those obtained at autopsy.
After continuous-flow LVAD support, the morphology of the aortic wall media was altered in all of our patients. The clinical relevance of these findings is unknown.
连续流左心室辅助装置（LVAD）可提供持久、可靠且节能的长期支持。然而，连续流的生物学效应尚未完全明确。因此，我们研究了心力衰竭患者在接受连续流LVAD长期循环支持前后的主动脉壁形态。
在升主动脉下半部应用部分主动脉阻断血管夹后，我们获取主动脉壁组织样本，然后连接泵的流出移植物。样本取自11例LVAD植入时患有严重心力衰竭的患者（9例男性和2例女性，平均年龄65±7岁）。我们在心脏移植后（n = 5）或尸检时（n = 6）获取了匹配的标本。这些标本取自升主动脉远端，远离主动脉吻合部位。组织切片用苏木精和伊红、莫瓦特五色染色法和马松三色染色法染色。对所有切片进行平滑肌肌动蛋白免疫组织化学检测。为评估主动脉壁中层的形态，我们对组织切片的中层厚度、中层退行性改变、平滑肌细胞（SMC）排列紊乱和减少、弹性纤维断裂和减少、中层纤维化和动脉粥样硬化改变进行定量分级。
平均支持时间为140±136天（范围87至580天）。LVAD支持前后获取的标本的组织学评估和比较显示，LVAD支持后中层变性、SMC减少、弹性纤维断裂、中层纤维化和动脉粥样硬化改变的病灶显著增加。LVAD支持后平均中层厚度无显著差异。我们在移植时获取的样本和尸检时获取的样本之间观察到了类似的变化。
在连续流LVAD支持后，我们所有患者的主动脉壁中层形态均发生了改变。这些发现的临床相关性尚不清楚。
