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Destination Unknown: The Ventricular Assist Device and the Advance of Technology

2012; Wiley; Volume: 60; Issue: 1 Linguagem: Inglês

10.1111/j.1532-5415.2011.03757.x

1532-5415

Daniel D. Matlock,

Cardiac Structural Anomalies and Repair

Left ventricular assist devices (LVADs) are a true feat of modern bioengineering. These devices suck blood from the left ventricle and force it into the aorta at a pressure high enough to sustain life. First approved by the Food and Drug Administration in 1994, these devices have enjoyed a recent surge in use because of advances in the technology. Initially, LVADs were pulsatile, with a pumping mechanism that attempted to mimic the pulse pressure of the native heart. Today, continuous-flow LVADs, which are smaller and have fewer moving parts, have largely replaced these pulsatile devices.1 LVADs are implanted to bridge people to transplant (or to candidacy for transplant) or as “destination therapy” (DT). To many, DT LVADs provide an attractive solution to fill the void between the large number of people needing a transplant and the small number of people receiving them.2 The results of the early randomized trials of pulsatile LVADs were not impressive. Even though they were associated with a 48% relative risk reduction in all-cause mortality compared with maximal medical management, 2-year survival statistics were dismal, at 23% in the pulsatile LVAD arm and 8% in the medical-therapy arm, with 25% of people in the LVAD arm dying of severe sepsis.3 A more-recent trial comparing continuous-flow LVADs with pulsatile LVADs demonstrated 58% 2-year survival with the continuous-flow devices, versus 24% with the pulsatile devices.4 The continuous-flow devices also had fewer complications and resulted in significantly greater functional capacity and quality of life.4 As a result, there has been rapid growth over the past few years in the overall use of LVADs, with 712 being implanted in 2009 and 614 in the first half of 2010; 97% of these were the new continuous-flow devices.1 In this issue of the Journal of the American Geriatrics Society, Vitale ahnd colleagues use a case study to call for guidance in the use of LVADs in older adults.5 They write about a 70-year-old man who received a LVAD for DT and then ultimately did poorly. The authors hypothesize that his poor outcome could have been predicted preoperatively using clues such as falls and gait disturbance from his prior stroke. Indeed, a fall that disconnected his LVAD's external power supply for 6 minutes left him with an ultimately fatal anoxic brain injury. The authors noted that people who have received LVADs ranged from aged 19 to 88; somewhere in this country, 88-year-olds are receiving LVADs! Individuals like the one the authors describe will likely become more common because the main reason that a person becomes ineligible for a heart transplant is advanced age.1 The authors were correct in saying, “we can expect a continued increase in the numbers of older adults considered for this therapy.” It is likely that the authors are correct in saying that a consideration of geriatric syndromes could better predict who will benefit from the LVAD, but there is a nuance in that some geriatric syndromes may be partially reversible with the LVAD. Take frailty for example; imagine a man with end-stage heart failure and frailty from significant cardiac cachexia. He might have trouble dressing, bathing, walking, and toileting because his heart cannot supply enough blood to meet the demands of his body. Presumably, greater cardiac output (from a LVAD) could improve his functioning and reverse the frailty. Pulsatile and continuous-flow devices were both associated with significant improvements in exercise capacity and walk distances, common aspects of the frailty syndrome.3, 4 Thus, using geriatric syndromes to improve patient selection for the LVAD will require paying careful attention to measures that distinguish LVAD-resistant geriatric syndromes from LVAD-responsive geriatric syndromes. That said, the author's argument that geriatric syndromes should be considered when selecting individuals for LVADs is well made and is an important research area to which geriatricians can and should contribute. In their article, Vitale and colleagues used the framework of risks, benefits, and burdens to discuss LVADs. This is the proper framework to consider because these are exactly the issues that patients and families should think about when confronted with making the decision of whether to receive a LVAD. A decision like this that involves significant trade-offs is ripe for a formal shared decision-making process. This could take the form of trained decision coaches (a heart failure nurse or a palliative care team) who sit with the patient and the family and discuss the risks, benefits, and burdens. The shared decision-making could also be augmented with a formal decision aid—a tool that could help patients and families absorb the necessary information at their own pace. In other decisions, decision coaches and decision aids have been shown to help patients improve their knowledge, clarify their values, and reduce their decisional conflict.6, 7 Some programs are using palliative care referrals at the time of LVAD implantation to help patients and families clarify their goals of care and make informed decisions, as well as preparing patients and families should things not go well.8 LVADs cost nearly one-quarter of a million dollars.9 Some may look at the data for LVADs and still be unimpressed because a 58% 2-year survival is still low for such an aggressive and expensive therapy, but the technology will continue to improve. Already, third-generation LVADs with only one moving part are being studied in randomized trials (clinicaltrials.gov number, NCT01166347). Fourth-generation, wireless devices are currently under development that will probably have a much lower rate of infection by not having a wire that needs to be connected to a power source outside the body.10 Who knows what the fifth- and sixth-generation devices will bring? In other industries, innovations often improve efficiencies and lower costs. In health care, innovations often improve quality or quantity of life or both, albeit at an increased cost. LVADs are a perfect example of this. The number of people in the United States aged 65 and older will increase from 40 million in 2010 to 87 million in 2050.11 This “silver tsunami” will place a significant strain on the healthcare system.12 New technologies are increasingly expensive and decreasingly beneficial—a phenomenon that has been called “flat of the curve medicine.”13 The RAND Corporation developed the Future Elderly Model to study the effects of technology, disability, obesity, and chronic disease on future medical spending and concluded that society's greatest spending risk was “not from demographic and health trends, but rather from medical technologies.”14 Because of problems with reimbursement, increasing numbers of primary care physicians are no longer accepting Medicare. Perhaps more troubling, few trainees are pursuing fields in primary care despite a clear association between primary care physicians and quality.15, 16 Is it right to spend scarce healthcare dollars on LVADs while Medicare beneficiaries increasingly struggle to find primary care physicians who will even see them? This is not an easy question; this author has a Medicare patient with a LVAD who is hiking (granted, he is 33 years old). As a clinician, it would be difficult to deny this therapy to someone based on cost alone, and these cost decisions should certainly not be done at the bedside, but the recent economic troubles combined with the calls that Medicare is running out of money are prima facie evidence that the long-overdue debate about distributive justice cannot be ignored much longer. LVADs are yet another example of why the United States needs an explicit process of considering the benefits and costs of a therapy to transparently decide what is truly “reasonable and necessary.” Dr. Matlock would like to thank Tanner Caverly, MD, for his helpful comments on an earlier version of this manuscript. Conflict of Interest: Dr. Matlock is supported by Grant K23AG040696 from the National Institute on Aging. Author Contributions: Dr. Matlock was the sole contributor to this article. Sponsor's Role: The content is solely the responsibility of the author and does not necessarily represent the official views of the National Institute on Aging or the National Institutes of Health.