Hemolysis is a well-documented complication in patients with mechanical heart pumps. When red blood cells are damaged as they pass through a device, hemoglobin is released into the bloodstream, which over time can contribute to kidney injury, anaemia and other organ complications. Despite the clinical relevance of hemolysis, no in vitro hemolysis data for the approved device have previously been published – making this the first head-to-head laboratory comparison of two total artificial hearts using fresh human blood.

The study was conducted using human whole blood which was circulated through each device in a circulation model mimicking half of the human cardiovascular system (left side, or systemic, circulation). The results show that Realheart® TAH produced a significantly lower normalised hemolysis index (mgNIH), 18.11 ± 3.53 mg/100 L, compared with 37.15 ± 12.42 mg/100 L, than the comparator (p < 0.05). Further, plasma free hemoglobin, a direct marker of red blood cell destruction, was nearly twice as high in the comparator samples after six hours, and only the comparator significantly reduced the number of intact red blood cells relative to both the Realheart® TAH and the static control. In summary, Realheart® TAH causes significantly less harm to red blood cells than the market-approved alternative.

These results add to a growing body of experimental preclinical evidence, as well as computational modelling, indicating a favourable hemolysis profile for the Realheart® TAH design. The current study confirms that pattern in human blood, which is roughly twice as sensitive to mechanical damage as alternative experimental options (e.g. bovine blood). The tests in this study were limited to systemic circulation, and in the next step full-body circulation testing will bring the preclinical evaluation closer to the conditions the device will face in patients.

"This was our first study on human blood, and these data show that the Realheart® TAH causes significantly less blood damage than the only market-approved alternative, which is a critical biomarker evaluated by regulatory agencies. With this piece of the puzzle in place, we have moved on to more comprehensive evaluations, including full-body circulation testing, as part of our stepwise preparation for late-stage testing of our product. We have chosen to use human blood as this is more easily damaged than animal blood, which is typically used, thus giving a more clinically relevant risk assessment" says Ina Laura Perkins, CEO, Realheart.

Read the full study: http://doi.org/10.1111/aor.70149