March 21, 2002
ATLANTA, Georgia (ACC) -- One of the most anticipated reports of this Scientific
Session—the findings from the MADIT II trial—revealed Tuesday,
March 19, 2002 that the prophylactic use of an ICD in
patients with a previous myocardial infarction (MI) and reduced
left ventricular ejection fraction significantly reduced the
risk of death.
“Prophylactic implantation of a defibrillator in addition to
medications should be considered as a recommended therapy in
this patient population,” said Arthur J. Moss, MD, from the
University of Rochester Medical Center, in front of a packed
house in Hall D.
The four-year trial included 1,232 patients from 76 centers in
the United States and Europe. Patients with a prior MI and a
left ventricular ejection fraction of 0.30 or less were randomly
assigned in a 3:2 ratio to receive an ICD (742 patients) or
conventional medical therapy (490 patients), with all-cause
mortality as the primary end point. Electrophysiologic testing
or inducible ventricular arrhythmias were not eligibility
criteria for MADIT II.
During 20 months of follow up of the study group, there was a 31
percent reduction in the relative risk of mortality among
patients in the ICD group as compared those in the conventional
therapy group, Dr. Moss reported.
Because of the reduced risk of mortality seen in the trial, the
Data Safety and Monitoring Board stopped the trial early
(November 2001). The results are especially significant, Dr.
Moss said at a news conference later in the day, because ICD
therapy was “on top of optimal medical management.” Use of beta
blockers in both treatment arms, for example, was 70 percent,
and use of statins was 67 percent in the ICD group and 64
percent in the conventional therapy group.
ICD therapy was associated with the expected rates of
device-related complications, Dr. Moss said, but, more
importantly, was also associated with a higher rate of new or
worsened heart failure than was conventional therapy. While this
was a troublesome finding, he said, the research team speculated
that effective treatment of potential lethal arrhythmias leads
to longer survival, thus allowing heart failure to develop.
Economic implications loom
The potential patient population that could benefit from
prophylactic treatment is large—an estimated three to four
million patients have coronary artery disease and advanced left
ventricular dysfunction in the United States, with an estimated
400,000 new cases annually.
“If a meaningful number of these patients receive an ICD
prophylactically, the cost to the health care system would be
substantial,” Dr. Moss said. But “market forces,” he argued,
would eventually drive down the cost of this therapy.
Repeating a warning from an editorial he wrote in Circulation
last year, ACC Immediate Past President Douglas P. Zipes, MD,
who moderated the news conference, said that, at their current
cost, expanded use of ICDs “could have profound implications for
the health care budget.”
To reduce the potential economic impact, Dr. Zipes reiterated
his call for device companies to consider making two different
classes of ICDs: a cheaper, stripped down version with limited
capabilities for lower-risk patients, and the more sophisticated
devices currently being manufactured.