RWTH Aachen University
Perfecting a Life-Saving Blood Pump
The local CATS environment is totally Macintosh. All 15 members of the CATS staff, including eight doctoral students and seven non-scientific staff members and undergraduate students, use Power Macs and PowerBooks. This has given CATS a highly efficient engineering workflow for the DeBakey VAD analysis. From model preprocessing to FEA analysis to visualization to creating reports, all work stays on the Mac platform. CATS uses Workgroup Manager, included with Mac OS X Server, to interface the desktops with the cluster. The team views the results of FEA analyses on its Mac desktops using EnSight postprocessing software from CEI, Inc.
“This workflow gives us a clear advantage in terms of convenience and efficiency, and that’s why we chose Macs as desktops,” says Behr. “I cannot overestimate the importance of this to our work on the DeBakey VAD. Previously, we always had to use machines like SGI or Sun for scientific work and desktop machines for office work. Finally, with Mac OS X, these two worlds have come together.”
“The real long-term hope for cardiac patients lies in tissue engineering that could help regenerate real hearts. That would eventually put us out of business as pump designers, and that would be a good thing.”
CATS selected the Xserve cluster for its work after an evaluation that compared it with an AMD Opteron system. “We ran our FEA code to make performance comparisons between high-end AMD Opteron processors and Apple’s G5s,” says Behr. “During the decision phase, we were able to test the performance of the Apple solution with our application. That helped convince us. The results were very satisfactory, and we quickly decided on the Apple system.”
CATS also had environmental concerns. Because of the small size of its server room, noise, heat emission, and power consumption were significant factors in its choice of cluster technologies. The Xserves, which use only 120 watts compared to about 200 watts for the Opteron-based system, enabled CATS to reduce air conditioning costs and keep overall costs low. CATS also found the Xserves significantly quieter.
Looking Ahead
Behr wants to give patients a pump with a longer lifespan. “The real long-term hope for cardiac patients lies in tissue engineering that could help regenerate real hearts,” says Behr. “That would eventually put us out of business as pump designers, and that would be a good thing. But our goal today is to produce a pump that could last a patient many years.”
The work at CATS is funded in part by MicroMed Cardiovascular, Inc., which markets the DeBakey VAD; by the National Science Foundation, through Rice University in Houston; and the German Science Foundation. “There is a great deal of interest in these projects,” says Professor Behr.
And there should be interest. CATS is relying on Apple server and desktop technology to refine a product that is literally extending and saving the lives of hundreds of adults and children.
CEI EnSight and the Mac
CATS engineers examine the results of CFD analyses on Mac desktops using EnSight post-processing software.
“EnSight and the Mac platform make a strong combination for Professor Behr’s application,” says Jay Lyerly of CEI, makers of EnSight. “Any organization using in-house code will find that it translates immediately to the Mac in a very simple way.
“Many of our customers have spent a lot of time maintaining graphics drivers. All those issues go away with the Mac, which comes with high quality built-in Mac OS X graphics drivers.”
NASA, Dr. DeBakey, and the Houston Connection
In the 1990s, NASA scientists began working with Dr. Michael E. DeBakey of Houston’s Baylor College of Medicine to develop a miniaturized ventricular-assist device (VAD) called the NASA/DeBakey heart pump. Today it is marketed by MicroMed CardioVascular as the DeBakey VAD.
Marek Behr became involved in the development of VADs as an assistant professor at Rice University, across the street from Baylor. His ongoing Houston collaborators in blood flow modeling include Professors Matteo Pasquali of Rice University’s Department of Chemical and Biomolecular Engineering, Yukihiko Nosé of the Baylor College of Medicine’s Department of Surgery, and Fazle Hussain of the University of Houston’s Department of Mechanical Engineering.
