March 6 - 8, 2017 | Berlin
LEADING ENGINEERING SIMULATION CONFERENCE
Heart failure affects millions of people and is with 40 % one of the leading cause of death. The lack of donor hearts limits number of heart transplantations – only a small fraction can profit from this therapy. There is, however, an alternative therapy: the transient or permanent implantation of a rotational blood pump, which assists the failing heart. These blood pumps usually are fast rotating axial or centrifugal pumps, miniature in size and implanted in the vicinity of the heart. This has become a clinical practice, about 35 000 patients so far have received such a therapy. Most prominent recipient of such a blood pump was Dick Cheney, former Vice President of the United States. He was on the device for 22 month. Within this waiting time a donor heart was found and was successfully implanted. Dick Chaney still lives with his new heart.
As successful these blood pumps are, as problematic is their function in the patient´s body: after two years on the device, 80 % of the patients have suffered a major adverse event, which can either be a stroke, a bleeding or an infection. Because a pressure of about 15 000 Pa has to be generated, blood has to be accelerated to velocities much higher than found in the human body.
Computational Fluid Dynamics (CFD) is used to compute the blood flow with in the rotational blood pump. A mesh of 11 million cells is used. Once the flow field is computed, attention is focused on areas which high shear stress – which activate platelets - and on areas with flow separations – where platelets can deposit and form clots. The ability to identify critical regions in the rotational blood pump makes CFD an important tool for the development.