Swartz Michael F, DiVincenti Louis, Smith Karen, Westcott Robin, Belmont Kevin, Harris William, Gensini Francisco, Alfieris George M
Department of Surgery, University of Rochester Medical Center, Rochester, New York.
Department of Veterinary Medicine, University of Rochester Medical Center, Rochester, New York.
J Card Surg. 2017 Feb;32(2):126-132. doi: 10.1111/jocs.12931. Epub 2017 Jan 9.
There are minimal circulatory support options for patients with a failing Fontan. The Heartmate II (HMII) left ventricular assist device (Thoratec, Bedford, MA) in its packaged state cannot augment caval/pulmonary arterial blood flow.
We hypothesized that a modified HMII pump could augment caval and pulmonary arterial blood flow.
A bifurcated ringed Gore-Tex graft (W. L. Gore & Associates, Flagstaff, AZ) was sewn to the HMII inflow, and the outflow graft transected and tapered from 16 mm to 8 mm in diameter. In three sheep, the inflow and outflow grafts were anastomosed end-to-side to both cava and the pulmonary artery.
Following baseline measurements, the pump speed was increased to 8000 revolutions per minute (RPMs). Compared to baseline, at 8000 RPMs, there were no significant differences in mean arterial, central venous, or pulmonary arterial pressure. However, there was a significant decrease in right ventricular diastolic diameter (3.1 ± 0.1 vs. 1.8 ± 0.2 cm, R = 0.6, p = 0.02) and similarly a decrease in pulmonary arterial pulse pressure (8.5 ± 2.1 vs. 2.1 ± 2.9 mmHg, p = 0.01). As pump speed increased, there was a corresponding increase in pump flow and power, with a decrease in pulsatility index.
These findings suggest that the HMII may be modified to provide caval/pulmonary circulatory support for the failing Fontan circulation.
对于功能性单心室（Fontan）循环衰竭的患者，循环支持选择极少。处于包装状态的Heartmate II（HMII）左心室辅助装置（Thoratec公司，马萨诸塞州贝德福德）无法增加腔静脉/肺动脉血流量。
我们推测改良后的HMII泵可增加腔静脉和肺动脉血流量。
将一个分叉的带环Gore-Tex移植物（W. L. Gore & Associates公司，亚利桑那州弗拉格斯塔夫）缝合到HMII的流入端，流出移植物切断并从直径16毫米逐渐变细至8毫米。在三只绵羊中，流入和流出移植物分别与腔静脉和肺动脉进行端侧吻合。
在进行基线测量后，泵速增加到每分钟8000转（RPMs）。与基线相比，在8000 RPMs时，平均动脉压、中心静脉压或肺动脉压无显著差异。然而，右心室舒张直径显著减小（3.1±0.1对1.8±0.2厘米，R = 0.6，p = 0.02），肺动脉脉压也同样减小（8.5±2.1对2.1±2.9 mmHg，p = 0.01）。随着泵速增加，泵流量和功率相应增加，搏动指数降低。
这些发现表明，HMII可能经过改良后可为功能性单心室（Fontan）循环衰竭提供腔静脉/肺循环支持。
