In vitro Hemocompatibility Evaluation of the HeartWare Ventricular Assist Device Under Systemic, Pediatric and Pulmonary Support Conditions

Abstract

The development of adult use right ventricular assist devices (RVADs) and pediatric left ventricular assist devices (pediatric LVADs) have significantly lagged behind compared to adult use left ventricular assist devices (LVADs). The HeartWare ventricular assist device (HVAD) intended to be used for adult’s systemic support, is increasingly used off-label for adult pulmonary and pediatric systemic support. Due to different hemodynamics and physiology, however, the HVAD’s hemocompatibility profiles can be drastically different when used in adult pulmonary circulation or in children, compared to its intended usage state, which could have a direct clinical and developmental relevance. Taking these considerations in mind, we sought to conduct in vitro hemocompatibility testing of HVAD in adult systemic, pediatric systemic and adult pulmonary support conditions. Two HVADs coupled to custom-built blood circulation loops were tested for 6 hours using bovine blood at 37°C under adult systemic, pediatric systemic, and adult pulmonary flow conditions (flow rate = 5.0, 2.5, and 4.5 L/min; differential pressure = 100, 69, and 20 mm Hg, respectively). Normalized index of hemolysis for adult systemic, pediatric systemic, and adult pulmonary conditions were 0.0083, 0.0039, and 0.0017 g/100 L, respectively. No significant difference was seen in platelet activation for these given conditions. High molecular weight von Willebrand factor multimer degradation was evident in all conditions (p < 0.05). In conclusion, alterations in the usage mode produce substantial differences in hemocompatibility of the HVAD. These findings would not only have clinical relevance but will also facilitate future adult use RVAD and pediatric LVAD development.

Hemolysis Testing In Vitro: A Review of Challenges and Potential Improvements

“…Of these publications, only primary sources of experimental hemolysis were included (n = 9). 6,[27][28][29][30][31][32][33][34] As a common comparative measure for reproducibility, the absolute coefficient of variation (CV) was calculated, which is the ratio of the standard deviation to the mean value of a series of measurements. The CV was calculated separately for all reported test conditions, totaling 31 collected measurement series with an average of 51 ± 30%.…”

Hemodynamic Evaluation of a Centrifugal Left Atrial Decompression Pump for Heart Failure with Preserved Ejection Fraction

“…The use of certain pumps can lead to the degradation of red blood cells due to higher shear stress [ 35 ], which has been linked to blood dysfunction and hemolysis, presenting a major limitation for these devices. Threshold shear stress values have been identified to detect dysfunction [ 44 , 45 ], with values of 9, 50, and 150 Pa corresponding to degradation of Willebrand factor, platelet activation, and red blood cell rupture (hemolysis) [ 24 , 37 , 46 , 47 , 48 ]. To improve hemocompatibility and reduce dysfunction, designers have focused on the geometric parameters of pumps, such as the wrap angle, number of blades, blade thickness, impeller diameter, and gap size [ 49 , 50 , 51 , 52 , 53 , 54 ].…”

Extracorporeal Membrane Oxygenation-Induced Hemolysis: An In Vitro Study to Appraise Causative Factors

“…We used four ECMO circuits (Permanent Life Support System (PLS), Maquet CP, Rastatt, Germany) throughout our experiments ( Figure 1 ). After each use, the ECMO circuit was thoroughly washed with saline and run in 0.6% Medizyme (Whiteley Medical Pty Ltd., Hornsby, NSW, Australia) solution rotating at a constant speed (2000 revolutions per minute (RPM)) for at least 12 h to dissolve all possible blood residue according to previously validated washing protocol [ 20 , 21 ]. After washing with Medizyme, 80% ethanol solution was circulated through the circuit for 1 h at 2000 RPM.…”