Insanity of Left Ventricular Assist Therapy Doing the Same Thing and Expecting Different Results

If you can measure that of which you speak and can express it by a number, you know something of your subject; but if you cannot measure it, your knowledge is meager and unsatisfactory. Lord Kelvin

The success or failure of LVAD therapy can be measured in a number of ways. The landmark clinical trials, REMATCH² and InTREPID³ defined success in terms of mortality and morbidity, as compared to standard medical therapy. Indeed these are the primary benchmarks used by the United States Food and Drug Agency when evaluating a device for market approval. On a grander scale, success may be measured in terms of the popularity or utilization of the therapy. In this respect, LVAD therapy could be deemed as an abject failure; for, thirty years ago following the Office of Technology Assessment report⁴ on The Artificial Heart: Cost, Risks, and Benefits identified the annual need to be on the order of 100,000 in the U.S., and 200,000 worldwide.

For many of these intervening years, it was believed that the barriers to widespread growth of this therapy were the technology itself: the unsatisfactory safety and efficacy of the devices. Now that current LVAD’s are sufficiently small, quiet, and durable; and that serious complications of infection and thromboembolic events have been mitigated, we must look to a different metric of success.⁵ Which is precisely what Oppenheimer & Co. did in a recent (May 2011) survey of cardiac surgeons.⁶ When asked “what are the greatest factors driving wider adoption of LVADs for destination therapy?” the overwhelming response was… “Portability and device wear profile.” Not “small size,” “easier implant strategy,” and “cost” — which were in fact at the very bottom of the list. But why? The external hardware and accoutrements are nothing but incidental accessories. They cannot affect outcomes. Could they?

Why not ask the patients themselves?

The patient’s response to this question is reported in the systematic review article by Brouwers et al.¹ And the response is unanimous: Quality of Life. Their survey, which encompasses 16 quantitative studies of patient reported outcomes (PROs) from 1999 to the present, is also a reminder that patients have been making this plea for as long as they have been asked the question. In other words, it should not come as a surprise that anxiety, depression, uselessness, and other psycho-social pathologies are at variance with the well-intended goal of LVAD therapy.

Several months prior to the 1982 landmark implantation of the first “permanent” artificial heart into Dr. Barney Clark, Dr. Robert Jarvik, was quoted by Scientific American,

If the artificial heart is ever to achieve its objective, it must be more than a pump. It must also be more than functional, reliable and dependable. It must be forgettable.⁷

Even 8 years prior, in 1973, the Artificial Heart Assessment Panel, commissioned by the National Heart and Lung Institute, warned of the psychiatric and social implications of this technology. ⁸

An obvious question, therefore, is “What can/should we do now that we have not already done over the past four decades?” Brouwers and colleagues provide several insightful and important clinical guidelines that are important to both outcomes and to decision making, defined in a holistic sense. What they do not mention are remedies that may be contributed from the engineering community, of which this author is a member. Those of us who develop this technology are also beholden to the tenet, primum non nocere, perhaps not by oath, but certainly in spirit. We may not be qualified to rule upon best practices of medicine, but it is our obligation as “part of the problem” to also be part of the solution. This includes an obligation to assure the responsible use of the technology.

To wit, this engineer respectfully suggests that the patients, their caregivers, and members of their support system become more completely engaged in decision making involving their care. This evolution is already occurring, described quite eloquently in the book Complications by Atul Gawande, MD:

A decade or so ago, doctors made all the decisions; patients did what they were told. Doctors did not consult patients about their desires and priorities and routinely withheld information — sometimes crucial information, such as what drugs they were on, what treatments they were being given, their diagnosis; patients were even forbidden to look at their own medical records: it wasn’t their property. … They were regarded as … too fragile and simple minded to handle the truth, let alone make decisions.⁹

Having now entered an era of increased patient involvement, we should provide them tools to make rational choices, based on their true desires and priorities, despite the duress of being critically ill. For example, the use of online social networks, and decision support software¹⁰ may provide patients with group support, and the opportunity to consider more deeply the costs and benefits of LVAD therapy — over and above the 30–60 minute consultation with the cardiac surgeon that is typical of many (most) centers. Such tools would both prevent patients from accepting LVAD therapy who would ultimately grow to regret it, and hopefully, more importantly, provide patients with confidence that a foreign mechanical device in their bodies may in fact be preferable to the certain demise of standard care, or death.

The above remarks are not meant to shirk responsibility to further improve the LVADs themselves. Indeed, developers of the next generation of LVAD systems must focus greater attention on human factors design of peripherals, reduced power requirements, robust feedback-control and reduced invasiveness: to both diminish the encumbrance, and approximate the efficacy of cardiac transplantation.

In summary, Brouwers et al. is a clarion call to the LVAD community to direct their full attention to Quality of Life. They speak to the clinical community to increase clinical emphasis on PROs “to optimize the care of an increasingly growing population of LVAD patients.” To this may be appended an appeal to the bioengineering community to continue the pursuit of the truly “forgettable” LVAD.