The Total Artificial Heart: TAH Research with Human Subjects
TAH Research with Human Subjects
Research with human subjects is limited in order to protect individuals from being abused by the researchers or society’s pursuit of grander social objectives. In 1982, the FDA granted an investigational device exemption for permanent TAH implantation because of the absence of other life-prolonging therapies for patients with endstage cardiomyopathy or who are unable to come off circulatory assistance after heart surgery. This exemption was justified by these patients’ dire need and by the importance of information about how to treat this class of patients. Annas2 believes that the prognosis with a permanent TAH is so predictably poor that the exceptional authorization for TAH research is not warranted.
The physicians duty of beneficence to TAH-depend-ent patients constrains TAH research in three ways. First, as the current consent form recognizes, separate consents are required after TAH implantation before additional research burdens are imposed on TAH-dependent persons. Second, research in transplant-eligible patients should not endanger the success of a future transplant. Third, the vital dependence of human subjects on the implanted TAH means that decisions to turn off a TAH are akin to those involving the discontinuation of other life-prolonging treatment, rather than the decision to end an unsuccessful clinical trial.
TAH Consent and Termination
Several consent issues are raised by TAH implantation including: 1) whether it is possible to obtain TAH consent from critically ill patients, and 2) whether and by what mechanism the TAH may be discontinued in advance of a patients death. Click Here
Despite their dire clinical circumstances, patients do seem capable of giving meaningful consent to TAH implantation. The fact that potential recipients have refused the TAH after becoming aware of its comorbidity demonstrates that dire need does not make consent a foregone conclusion. However, consent from seriously ill persons is never entirely free of coercion by fear of death or transference inflation of the attending physician. Rather than voiding consent, as some suggest, the possibilities of coercion and transference serve as reminders that consent cannot confer absolute protection and thus does not confer unlimited license. The consent document merely symbolizes and summarizes the consent process and should not be analyzed as if it adequately represents the consent process.
For procedures, like TAH implantation, that involve a continuing treatment rather than a discrete intervention, informed consent should be viewed as an ongoing agreement, rather than as a discrete event. This process should allow for the possibility that the research interests and patient interests might diverge during TAH treatment and should anticipate complications which might lead to consent being withdrawn.