Ethical Aspects in Trials of Implantable Medical DevicesEthical Aspects in Trials of Implantable Medical Devices

To the Editor: Dr Connolly and colleagues¹ found that pacemaker therapy did not reduce the risk of recurrent syncope in patients with vasovagal syncope. Patients in the control group all underwent pacemaker implantation, but their pacemakers were set for sensing only, without pacing in the event of a dysrhythmia. The authors justified this nontherapeutic surgical intervention by noting that control patients could have their devices activated for pacing once the study had been completed. Although there is controversy about the ethical aspects of such sham surgery,^{2 - 3} this study is unique in that the patients were left with an implanted device.

Three things could be done with the pacemakers in the control patients at the conclusion of such studies. First, they could be activated, so that the control patients would receive pacing. However, this would be inconsistent with the results of the blinded trial, and would thus not be an evidence-based intervention. Second, they could be left inactivated in situ. However, this would be ethically unacceptable, as it would expose patients to the long-term risks and discomforts of a pacemaker, with no prospect of benefit. Third, and in my judgment the only ethically acceptable alternative, would be to explant them, exposing patients to the risks of a second, and possibly more complex, surgical procedure. Thus both surgical procedures, implantation and explantation, must be considered among the potential risks to control patients in sham surgery studies involving implantable devices, and must be weighed against the benefit of the scientific knowledge gained.²

It is thus important to know what patients were told during the informed consent process about the disposition of the pacemakers at the conclusion of the study, in the event the device proved ineffective. It also would be of interest to know what was actually done with the devices, as well as the reaction of patients. In the study of nigral fetal cell transplants for Parkinson disease,⁴ for instance, some participants who received sham surgery apparently felt misled at the study's conclusion when they were not permitted to receive fetal grafts after this intervention proved ineffective.⁵