Brigham and Women's Hospital and Harvard Medical School, Boston, MA, United States.
Brigham and Women's Hospital and Harvard Medical School, Boston, MA, United States.
Trends Cardiovasc Med. 2020 May;30(4):223-229. doi: 10.1016/j.tcm.2019.05.013. Epub 2019 Jun 4.
Early generation left ventricular assist devices (LVAD) for treatment of refractory heart failure attempted to mimic the pulsatility of a native heart and were bulky and less durable due to valves within the inflow and outflow pathways. The next disruption came with the introduction of continuous flow pumps characterized by a low-pulse pressure circulation. Since the mechanism of action did not involve displacement of blood, these pumps were much smaller and less noisy in part due to fewer moving parts. Such devices include the HeartMate II axial-flow pathway pump which is implanted thoraco-abdominally and the HVAD, a centrifugal-flow pathway pump which is smaller and is implanted entirely within the thoracic cavity and uses a combination of hydrodynamic and magnetic levitation of the internal rotor. These pumps improved survival compared with the early generation LVADs and in a trial, the HVAD demonstrated non-inferiority compared with the HeartMate II but with an increase in ischemic and hemorrhagic strokes. The HeartMate 3 LVAD is an intrapericardial centrifugal-flow pathway pump with a full magnetically levitated, frictionless rotor with a fixed intrinsic pulse. In a randomized trial, the HeartMate 3 "hybrid" pump was associated with near-elimination of pump thrombosis, a reduction in strokes of any type or severity and lower mucosal bleeding rates. Despite improvements in hemocompatibility, right heart failure and infections contribute to significant morbidity, and devices designed to be internally contained with a wireless power source and physiological flow characteristics are still required despite great strides in the field.
早期的左心室辅助装置（LVAD）用于治疗难治性心力衰竭，试图模仿原生心脏的搏动性，但由于流入和流出道内的瓣膜，装置庞大且耐用性较差。下一个突破是引入了连续流泵，其特点是脉冲压低循环。由于作用机制不涉及血液置换，这些泵体积更小，噪音更小，部分原因是运动部件更少。此类设备包括 HeartMate II 轴流途径泵，该泵植入胸腹部；HVAD，一种离心流途径泵，体积更小，完全植入胸腔内，采用内部转子的液动力和磁悬浮的组合。与早期的 LVAD 相比，这些泵提高了生存率，在一项试验中，HVAD 与 HeartMate II 相比显示出非劣效性，但缺血性和出血性中风的发生率增加。HeartMate 3 LVAD 是一种心包内离心流途径泵，具有完全磁悬浮、无摩擦的转子和固定的固有脉冲。在一项随机试验中，HeartMate 3“混合动力”泵与泵血栓形成的几乎消除、任何类型或严重程度的中风减少以及较低的粘膜出血率相关。尽管血液相容性得到了改善，但右心衰竭和感染导致了显著的发病率，并且尽管该领域取得了重大进展，仍需要设计为内部包含无线电源和生理流动特性的设备。
