on a per-patient basis, the mechanical circulatory support systems (MCSSs) being developed will be among the most costly therapeutic devices to date;
MCSSs may be coming into general use as the health care system is under growing scrutiny for the quality and cost of care and patients ' access to it; and
the heart, an organ that has special cultural symbolism and life-sustaining importance, is involved.
A 1989 IOM planning committee formulated nine questions to be addressed in this evaluation although, as seen in the preceding chapters, the committee's deliberations went beyond answering the questions. The committee's responses to the questions are very briefly summarized here.
What are the nature and magnitude of the target populations for which MCSSs may be applied?Once a fully implantable MCSS is established to be clinically useful for long-term cardiac support, many more patients will receive one than the current annual volume of 2,000 heart transplant recipients. The number of potential MCSS candidates in the primary group (those most urgently in need of cardiac support) is between 35,000 and 70,000 annually, but practical limits on the growth of this technology's use will hold patient volumes below this range, for perhaps 10 years. In the 2010-2020 period, if device and transplantation outcomes are then similar, potential use may grow substantially beyond this range.
Most of the devices implanted during the first decade of MCSS use will be VADs. As many as 10,000 to 20,000 of each year's primary group of patients have impairment of both of the heart's ventricles, however, and will be candidates to receive a total artificial heart (TAH) after these devices become available, likely between 2005 and 2010.
What are the alternative technologies for preventing and treating end-stage heart disease that may affect the need for MCSSs?For the foreseeable future, transplantation will remain the treatment of choice for end-stage heart disease. Current forms of treatment other than transplantation offer most patients only limited benefits, such as relieving symptoms but not significantly prolonging life. Early in the next century, advances in drug therapy may at least be able to delay the onset of end-stage disease for some patients, and perhaps prevent it.
What is the potential for MCSSs to prevent and treat end-stage heart disease, and what are the current technological and other barriers to their development?Almost three decades of research and development have overcome many technological barriers to developing a fully implantable