ABSTRACT
BACKGROUND:The mechanical valves used in the adult Luo-Ye pump have a large size and great destruction to blood, which are not suitable for infant ventricular assist pump. Therefore, designing and producing a high molecular valve with smal size and low incidence of thrombosis is a research hotspot. OBJECTIVE:To design and produce a valve of 20 mL infant Luo-Ye pump, and to test its basic functions and fatigue properties. METHODS:The size and shape of valve was designed with MASTERCAM software, polyurethane valve was obtained through producing the valve model and plastic injection;the static leakage, pressure drop and fatigue resistance of polyurethane valve were tested according to the ISO5840 requirements. RESULTS AND CONCLUSION:The polyurethane trefoil valve was produced, but the failure rate of plastic injection was high;the basic function of the trefoil valve met the ISO5840 requirements bascial y;after continuously operated 1.0×107 times, stroke volume of 20 mL Luo-Ye pump was changed 5.2%, and two polyurethane valves and valve leaflets did not change and damage. Polyurethane trefoil valve was designed and produced successful y;polyurethane valves could meet the needs of 20 mL Luo-Ye pump, which already have the ability to clinical trials.
ABSTRACT
To compare the effects on hemodynamics of univentricular support with that of biventricular support on experimental ischemic biventricular dysfunction so as to provide experimental basis for clinical usage of the Luo-Ye pump. Eight canines were placed with a left ventricular assist device (LVAD; left atrial-aorta bypass) and a right ventricular assist device (RVAD; right atrial-pulmonary artery bypass). Left anterior descending coronary artery(LAD) was ligated, three minutes later, the proximal of right coronary artery (RCA) was ligated to establish animal madel of acute ischemic biventricular dysfunction. First start the LVAD, and then RVAD was started five minutes later. The hemodynamic data were recorded including central venous pressure(CVP), cardiac output (CO), mean artery pressure(MAP), and pulmonary artery pressure(PAP) and pulmonary capillary wedge pressure (PCWP). During biventricular assist devices (BVAD) the hemodynamics were improved remarkably, MAP increased from 37.4 +/- 8.8 mmHg to 84.2 +/- 9.7 mmHg (P < 0.01) (the normal level), CO increased from 0.82 +/- 0.1 L/min to 1.33 +/- 0.12 L/min (P < 0.01), CVP decreased from 14.6 +/- 2.3 cmH2O to 4.2 +/- 1.5 cmH2O (P < 0.01), PCWP decreased significantly from 14 +/- 3.9 mmHg to 1.6 +/- 0.9 mmHg. These data suggest that LVAD during biventricular dysfunction could not improve the hemodynamics to normal level. Howere BVAD could increase CO and MAP to normal level and decrease heart work and myocardial oxygen consumption, which could help to improve myocardial metabolism and myocardial function. Therefore, BVAD is the first choice in treating severe biventricular dysfunction which was not respond to drug therapy and intra-aortic balloon pump (IABP).