The first fully implanted artificial heart (Abiocor Total Replacement Heart from Abiomed) was implanted this week at Robert Wood Johnson University Hospital (New Brunswick, NJ), marking the first ever fully implanted artificial "organ". (See story.)
This is a striking development, one my late father, a thoracic/abdominal surgeon had serious doubts would happen (I believe the word he used was "never"). He claimed hemolysis would be the artificial heart’s downfall, since mechanical valves are just too rough on red blood cells. Given developments made since he cast his doubts, however, and given the milestones achieved by Abiomed, I think he might have a different view today.
It is indeed striking that such a mechanical device would reach application first, when diseases like diabetes have demanded so much research and the fundamental solution of matching insulin output to current blood glucose levels is a function that appears so ripe for a practical, even fully implantable, closed-loop biofeedback system. However, it also points up the continued challenge of biomedical engineering toward systems that provide anything more than physical or structural solutions to disease, as opposed to systems that provide functions at the level of filtration, biofeedback-based drug delivery or other solution.
The complexities of producing an artificial organ are highlighted by looking at the casualties in the market for development of the artificial liver. Companies that have pursued this without success (so far!) include VitaGen, Daji Biosciences, Polygenetics, HepaLife Technologies, and Bioartis. Similar challenges have been seen in development of artificial kidneys, lungs and other organs. The liver provides such complex set of independent and interrelated functions that it may yet be many years (and more company casualties) before a viable clinical option is developed.
Even though the artificial heart, even a fully implanted one, need only provide cardiac output to match the patient’s physiologic needs, it creates complex demands for a viable device, encompassing effective management of pressure, minimized damage to red blood cells, biocompatibility and other demands, not least of which include managing the device’s energy supply (lithium batteries charged via external coils that transmit energy transcutaneously).
Abiomed notes that this milestone is a technical rather than financial achievement, since a great deal of continued engineering will need to be done to make a fully implantable artificial heart commercially feasible. For the time being, systems that are designed to provide "bridge to transplantation" capability, a lesser demand (e.g., not fully implantable), will have increased demand.
Unless and until cell biology, gene therapy or other biotech approaches are developed that can either create biological replacement tissue/organ or cure the underlying disease that otherwise leads to heart transplant, systems like Abiomed’s represent yet another example in which device solutions are not perfect (as discussed here, here and here) but they are available and in use here and now.
Posted via email from medmarket’s posterous
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