Correspondence
Implantable Cardiac Defibrillators
N Engl J Med 2002; 347:365-367August 1, 2002
- Article
To the Editor:
Moss et al. (March 21 issue)1 describe a randomized, controlled clinical trial designed to test the expansion of the indications for implanting a cardiac defibrillator. The maker of the defibrillator paid for the trial, which was conducted by experts in the procedure that uses the defibrillator. The results demonstrate an unquestionable 31 percent decrease in mortality among those who underwent the prophylactic procedure. The accompanying editorial by Bigger2 cites the need for additional data and longer follow-up and implies that expanding the indications for the procedure may be premature. Nevertheless, nationally prominent cardiologists perceive the results of the trial as clearly demonstrating the efficacy of expanded use of the procedure.3
If Blue Cross or Medicare had sponsored the same trial and if experts in clinical epidemiology had directed the research, would the investigators have used the same results to recommend wider application of the procedure? Would they have failed to describe an absolute survival benefit of only 5.6 percent, to specify the cost of the procedure, to estimate the cost per life saved, or to recommend longer follow-up before drawing conclusions? Would their article have received a high priority for publication, been accompanied by a two-page advertisement for its sponsor, or attracted widespread media attention? Even when investigators without financial conflicts of interest have conducted a clinical trial carefully, we still need to pay attention to who pays for and who performs the trial as we consider what the published results mean.
3 ReferencesRobert M. Donaldson, Jr., M.D.
Yale University School of Medicine, New Haven, CT 06520
robert.donaldson@yale. edu 1
Moss AJ ,Zareba W ,Hall WJ , et al. Prophylactic implantation of a defibrillator in patients with myocardial infarction and reduced ejection fraction. N Engl J Med 2002;346:877-883
Full Text | Web of Science | Medline2
Bigger JT . Expanding indications for implantable cardiac defibrillators. N Engl J Med 2002;346:931-933
Full Text | Web of Science | Medline3
Kolata G. Tiny heart devices reduce death rate, but cost is concern. New York Times. March 20, 2002:A1, A26.
To the Editor:
If one assumes a conservative one-time cost of $30,000 per cardiac-defibrillator implantation (range, $28,0001 to $57,7002), heeding the call of Moss et al. to provide an implantable cardiac defibrillator for the estimated yearly flow of 400,000 new patients would cost public and private payers $12 billion annually. This cost alone is three times the estimated 2003 budget for the Centers for Disease Control and Prevention.3 If the additional government spending required to cover these devices were contemplated in other contexts, it would rightly be debated as a costly new program that competes with others for scarce public funds. Yet as part of a health care entitlement, implantable cardiac defibrillators highlight the surprisingly limited opportunities for policymakers and the public to shape the development and use of new forms of technology. When they have been proved to be safe and effective, lifesaving treatments bring strong political and clinical claims for reimbursement, regardless of the broader implications.
3 ReferencesEric C. Stecker, M.D.
University of Michigan School of Medicine, Ann Arbor, MI 48109
estecker@umich.edu Harold A. Pollack, M.P.P., Ph.D.
University of Michigan School of Public Health, Ann Arbor, MI 481091
Olshansky B ,Loots D ,McGrory-Usset M . Implantable cardioverter defibrillator practices and costs at an academic medical center. J Cardiovasc Electrophysiol 2001;12:162-166
CrossRef | Web of Science | Medline2
Owens DK ,Sanders GD ,Harris RA , et al. Cost-effectiveness of implantable cardioverter defibrillators relative to amiodarone for prevention of sudden cardiac death. Ann Intern Med 1997;126:1-12
Web of Science | Medline3
Office of Management and Budget Web site. Washington, D.C.: Office of Management and Budget, 2002. (Accessed July 11, 2002, at http://www.whitehouse.gov/omb/budget.)
To the Editor:
Several issues should be addressed regarding therapy with an implantable defibrillator before widespread consideration of this treatment is recommended. The study by Moss et al. was not blinded. Patients were randomly assigned to receive a defibrillator or not to receive a defibrillator. Since the device is noticeable during examination, unrecognized bias may have been introduced in the form of preferential treatment for patients who received defibrillators. This potential bias could have been minimized if all enrolled patients had received a defibrillator and then been randomly assigned to activation or nonactivation of the device.
Enrique V. Carbajal, M.D.
Ryan G. Smith, M.D.
Veterans Affairs Central California Health Care System, Fresno, CA 93703
enrique.carbajal@med. va. gov To the Editor:
Moss et al. report that the survival of patients with a reduced ejection fraction after myocardial infarction improved with the implantation of a defibrillator. The defibrillator group was compared with patients receiving conventional therapy alone. Table 1 of the report shows very few differences between the defibrillator group and the conventional-therapy group in terms of their medical regimens; however, there is no mention in the table or the text of the article of the use of aspirin, anticoagulants, or other antiplatelet agents in either group. Given that prolonged aspirin therapy in high-risk patients has been shown to reduce the rate of death from vascular causes and to improve overall survival,1 could the survival difference between the two groups in the study by Moss et al. be attributable to a difference in their use of aspirin or other antiplatelet therapies?
1 ReferencesSusan E. Cohen, M.D.
Bronx Veterans Affairs Medical Center, Bronx, NY 10463
susan.cohen2@med. va. gov 1
Antiplatelet Trialists' Collaboration
CrossRef | Web of Science
To the Editor:
We could wait for the future analysis, mentioned by Bigger, of the results of electrophysiological testing performed during implantation of the defibrillator. But data regarding the effect on survival of the rates of defibrillator discharge are crucial for the interpretation of the results of the study by Moss et al. and should therefore have been included in their article.
Anil K. Gollapudi, M.D.
Veterans Affairs Medical Center, Wilkes-Barre, PA 18711To the Editor:
The fundamental issue is whether death due to ventricular tachycardia or ventricular fibrillation can be averted by implantation of a defibrillator in patients with severe ischemic cardiomyopathy. The clinical decision is whether to use drug therapy (amiodarone or sotalol) or a defibrillator. It is odd that Moss et al. did not compare defibrillator treatment with amiodarone or sotalol. The inevitable question is whether the defibrillator is superior to class III drugs — not whether it is superior to no antiarrhythmic therapy at all. Since no attempt was made to resolve this issue, the study leaves us in the same quandary in which we began.
Carl Spivack, M.D.
1120 Morris Park Ave., 4A, Bronx, NY 10461Author/Editor Response
The authors reply:
To the Editor: We fully agree with Drs. Carbajal and Smith that blinded studies are less subject to bias than unblinded ones. However, the use of sham implantations would not have been ethical or feasible, nor would it have resulted in a truly blinded study. Given that scheduled office visits to cardiologists were made almost equally often in both groups, with attendance rates above 90 percent, it is difficult to imagine that there could have been a treatment bias sufficient to cause a 31 percent decrease in the risk of death from any cause.
As Dr. Donaldson argues, it is reasonable when evaluating recommendations based on a study to take into consideration who paid for the study and who conducted it, but the study results themselves clearly stand. We would all like to know what the longer-term results will be, but we disagree that an absolute reduction in mortality of 5.6 percent (from 19.8 percent to 14.2 percent) with defibrillator therapy over an average follow-up period of 20 months is a small effect or one that would ethically preclude continued experimentation in patients. Should we withhold medical results because society, whether pressured by cardiologists or by the politics of health care delivery, may misuse them?
Like Drs. Stecker and Pollack and Dr. Donaldson, we are fully aware of the potential cost and reimbursement implications of our study and other studies of defibrillators.1,2 An evaluation of the cost effectiveness of treatment with an implantable cardiac defibrillator in our study is under way. Clinical trials designed to determine whether a specific type of therapy saves lives represent a first step in advancing the science of medical therapeutics. Only when therapy is shown to be scientifically efficacious should cost considerations come into play. We do not believe that policymakers should shape the development and use of new forms of technology before their therapeutic efficacy has been demonstrated — that would be putting the cart before the horse.
Regarding Dr. Cohen's concern, aspirin was used by 63 percent and 65 percent of patients in the defibrillator and conventional-therapy groups, respectively. The rate of discharge of the defibrillators is a relevant question raised by Dr. Gollapudi, and preliminary data indicate that defibrillator therapy for malignant ventricular arrhythmias accounts for the reduction in mortality. Complete analyses will appear in due course. The executive committee for the Multicenter Automatic Defibrillator Implantation Trial II (MADIT-II) decided not to use amiodarone or sotalol for comparison in the trial, as Dr. Spivak suggests, since the evidence that was available before the trial began indicated that class III drugs had no benefit and might cause harm in patients who had had a myocardial infarction.3,4
4 ReferencesArthur J. Moss, Ph.D.
W. Jackson Hall, Ph.D.
Wojciech Zareba, M.D., Ph.D.
University of Rochester Medical Center, Rochester, NY 14642
heartajm@heart.rochester. edu 1
Mushlin AI ,Hall WJ ,Zwanziger J , et al. The cost-effectiveness of automatic implantable cardiac defibrillators: results from MADIT. Circulation 1998;97:2129-2135
Web of Science | Medline2
Larsen G ,Hallstrom A ,McAnulty J , et al. Cost-effectiveness of the implantable cardioverter-defibrillator versus antiarrhythmic drugs in survivors of serious ventricular tachyarrhythmias: results of the Antiarrhythmics Versus Implantable Defibrillators (AVID) economic analysis study. Circulation 2002;105:2049-2057
CrossRef | Web of Science | Medline3
Singh SN ,Fletcher RD ,Gross Fisher S , et al. Amiodarone in patients with congestive heart failure and asymptomatic ventricular arrhythmia. N Engl J Med 1995;333:77-82
Full Text | Web of Science | Medline4
Julian DG ,Camm AJ ,Frangin G , et al. Randomised trial of effect of amiodarone on mortality in patients with left-ventricular dysfunction after recent myocardial infarction: EMIAT. Lancet 1997;349:667-674[Erratum, Lancet 1997;349:1180, 1776.]
CrossRef | Web of Science | Medline
