Heart Failure Division, Abbott, Burlington, Massachusetts.
Heart Failure Division, Abbott, Burlington, Massachusetts.
Ann Thorac Surg. 2022 Dec;114(6):2226-2233. doi: 10.1016/j.athoracsur.2021.11.065. Epub 2022 Jan 3.
A likely consequence of the discontinued distribution and sale of the HVAD System (Medtronic, Minneapolis, MN) will be an increase in replacement with the HeartMate 3 (Abbott, Chicago, IL) left ventricular assist device when device exchange is necessary. If part or all of the HVAD 10-mm-diameter outflow graft is retained during replacement, the HeartMate 3 will have to run at a higher speed than it would with its 14-mm-diameter graft.
A steady-state, in vitro study was run with 250-mm-long samples of HVAD, HeartMate 3, and half-HVAD/half-HeartMate 3 grafts and additionally 125- and 375-mm-long samples of the HVAD graft. Flows of 3.0, 3.9, 4.3, 4.7, and 6.0 L/min were applied to encompass expected clinical conditions.
At typical and high flow rates of 4.3 and 6.0 L/min, HeartMate 3 rotor speeds with the full HVAD graft had to be increased relative to those with the HeartMate 3 graft from 5350 to 5700 and 6350 to 6900 rpm, respectively, with power consumption increases from 3.7 to 4.3 W (16%) and 5.5 to 6.8 W (24%), respectively.
The study did not elucidate a severe consequence of using a remnant HVAD graft during pump exchange, but the incremental risks of a higher rotor speed, disadvantage to the patient in battery runtime, and the general benefit of complete conversion to the HeartMate 3 graft should be balanced against other procedural considerations. Complete graft replacement during HVAD-to-HeartMate 3 conversion remains the preferred approach from an engineering point of view.
停止 HVAD 系统（美敦力，明尼苏达州明尼阿波利斯）的分销和销售可能会导致在需要设备更换时，更多地使用 HeartMate 3（雅培，伊利诺伊州芝加哥）左心室辅助装置来替代。如果在更换过程中保留 HVAD 的 10 毫米直径流出移植物的一部分或全部，HeartMate 3 将不得不以比其 14 毫米直径移植物更高的速度运行。
对 HVAD、HeartMate 3 和半 HVAD/半 HeartMate 3 移植物的 250 毫米长样本以及 HVAD 移植物的 125 和 375 毫米长样本进行了稳态体外研究。应用 3.0、3.9、4.3、4.7 和 6.0 L/min 的流量，以涵盖预期的临床情况。
在典型和高流量（4.3 和 6.0 L/min）下，使用完整的 HVAD 移植物时，HeartMate 3 转子速度相对于使用 HeartMate 3 移植物的速度必须分别从 5350 增加到 5700 和从 6350 增加到 6900 rpm，功率消耗分别从 3.7 增加到 4.3 W（16%）和从 5.5 增加到 6.8 W（24%）。
该研究没有阐明在泵更换过程中使用 HVAD 移植物残余物的严重后果，但更高的转子速度、对患者电池运行时间的不利影响以及完全转换为 HeartMate 3 移植物的一般益处的增量风险应与其他程序考虑因素相平衡。从工程角度来看，在 HVAD 到 HeartMate 3 转换期间完全更换移植物仍然是首选方法。
