Frazier O H, Forrester Matthew D, Gemmato Courtney, Gregoric Igor D
Department of Cardiopulmonary Transplantation, Texas Heart Institute at St. Luke's Episcopal Hospital, Houston, Texas 77225-0345, USA.
J Heart Lung Transplant. 2007 Jun;26(6):646-8. doi: 10.1016/j.healun.2007.03.012. Epub 2007 Apr 16.
Long-term left ventricular assist device (LVAD) implantation is associated with an inherent risk of transient ischemic attacks (TIAs). When TIAs occur in patients who have undergone placement of a HeartMate XVE LVAD, the pump must be assumed to be the likely source of the TIA. The HeartMate XVE is unique in that it has a pumping surface of flocked Biomer and a pump housing and inlet cannula coated with sintered titanium. This design facilitates coating of the surfaces with the patient's own cells, usually within 48 hours of implantation, effectively eliminating the pumping surface as a source of thromboemboli. Similarly, neither the outflow conduit nor the porcine outflow valve have been shown to be sources of thromboemboli, as they are both subjected to the wash-out of pulsatile systolic pressure. In our experience, the only components vulnerable to pannus formation are the inflow conduit and its associated valve, and then only when the inflow conduit is distorted at implantation. We describe an illustrative case of a patient supported with a HeartMate XVE LVAD who suffered a device-related stroke that was attributed to the inflow conduit, which was distorted during implantation to configure the pump for the patient's narrow body habitus. The resultant disruption in laminar flow was the most likely cause of the TIAs and stroke. Therefore, documented TIAs in patients with an implanted HeartMate XVE are an indication for urgent pump replacement, even if pump performance is otherwise normal. In this case, the pump was exchanged for a smaller, continuous-flow HeartMate II LVAD.
长期植入左心室辅助装置（LVAD）存在短暂性脑缺血发作（TIA）的固有风险。当接受HeartMate XVE LVAD植入的患者发生TIA时，必须假定泵是TIA的可能来源。HeartMate XVE的独特之处在于它有一个植绒生物材料的泵表面以及一个涂有烧结钛的泵壳和进口插管。这种设计便于在植入后48小时内用患者自身细胞覆盖这些表面，有效消除泵表面作为血栓栓塞源。同样，流出管道和猪源流出瓣膜均未被证明是血栓栓塞源，因为它们都受到搏动性收缩压的冲刷。根据我们的经验，唯一易形成血管翳的组件是流入管道及其相关瓣膜，而且只有在植入时流入管道扭曲的情况下才会如此。我们描述了一个使用HeartMate XVE LVAD支持的患者的典型病例，该患者发生了与装置相关的中风，病因是流入管道，其在植入时因根据患者狭窄体型配置泵而扭曲。由此导致的层流中断很可能是TIA和中风的原因。因此，植入HeartMate XVE的患者出现记录在案的TIA是紧急更换泵的指征，即使泵的性能在其他方面正常。在这个病例中，将泵换成了更小的连续流HeartMate II LVAD。
