NEW ORLEANS — Medicare's policy of covering implantable cardioverter defibrillator therapy in patients with nonischemic dilated cardiomyopathy with a disease duration of 9 months or more was undercut by two studies presented at the annual meeting of the Heart Rhythm Society.
The studies by two separate teams of investigators independently showed that the risk of sudden cardiac death—and the benefit from implantable cardioverter defibrillator (ICD) therapy—was the same whether patients met the 9-month criterion or not.
The patients with nonischemic dilated cardiomyopathy who met Centers for Medicare and Medicaid Services (CMS) criteria for ICD implantation, except that their disease had been diagnosed less than 9 months earlier, had benefits similar to those seen in patients whose condition had been diagnosed at least 9 months earlier and who therefore were eligible for ICD coverage. The benefit was also seen in patients whose nonischemic dilated cardiomyopathy (NIDCM) was diagnosed less than 3 months earlier.
“These results suggest that any delay in ICD implantation will reduce survival benefit. Therefore, if ICD therapy is selected for a patient with nonischemic cardiomyopathy … then the ICD should be implanted without delay,” said Kelley P. Anderson, M.D., of the Marshfield (Wis.) Clinic.
In January, CMS expanded coverage for ICD therapy beyond patients with ischemic cardiomyopathy for the first time, to include selected individuals with NIDCM.
But to be eligible, patients had to have New York Heart Association class III or worse heart failure, a left ventricular ejection fraction of 35% or less, and—the focus of controversy—they had to have nonischemic dilated cardiomyopathy of more than 9 months' duration. Patients who had been diagnosed 3–9 months earlier would be eligible for reimbursement but only if they were entered in a special registry, the details of which the Heart Rhythm Society and CMS are still hammering out.
Patients with nonischemic dilated cardiomyopathy of less than 3 months' duration are ineligible for ICD coverage because CMS has deemed there is a lack of clinical evidence of benefit.
Dr. Anderson presented a new retrospective post hoc analysis of data from the prospective Defibrillators in Nonischemic Cardiomyopathy Treatment Evaluation (DEFINITE) trial, in which 458 patients with NIDCM were randomized to optimal medical therapy for heart failure with or without an ICD, regardless of the duration of NIDCM.
At 2.5 years of follow-up, survival in the 150 patients with nonischemic dilated cardiomyopathy of not more than 3 months' duration at randomization was 89.9%, after the investigators controlled for treatment assignment. This wasn't significantly different from the 84.0% rate in patients with NIDCM of greater than 3 months' duration. Similarly, survival in the 216 patients with NIDCM of 9 months' duration or less was comparable to that of patients with greater than 9 months' duration.
Moreover, among the subgroup of patients with nonischemic dilated cardiomyopathy of 3 months' duration or less at the time of randomization, those assigned to receive an ICD were 63% more likely to be alive at 2.5 years than were those randomized to optimal medical management. Similarly, those whose NIDCM had been diagnosed 9 months or less prior to ICD implantation were 52% more likely to survive to 2.5 years than were comparable patients randomized to medical therapy, he continued.
Late-breaker session cochair David S. Cannom, M.D., called the new DEFINITE data “very provocative,” adding, however, that he found troubling what he termed the “startlingly high” early arrhythmic event rate in the study population.
“The argument might be that you've picked a particularly vulnerable population that's suffering from an acute syndrome of some type—say, a viral etiology—that would get better over a short period of time anyway without an ICD,” said Dr. Cannom, director of cardiology at Good Samaritan Hospital, Los Angeles, and a past president of the Heart Rhythm Society.
His cochair, Sanjeev Saksena, M.D., commented that he'd be very interested to see serial ejection fraction data for the DEFINITE participants.
A significant improvement over time would suggest Dr. Cannom's hunch is correct.
“We are often pressured to intervene to put in an ICD in these patients with nonischemic cardiomyopathy [of short duration], and then 3 or 4 weeks later the ejection fraction has improved,” said Dr. Saksena, professor of medicine at Robert Wood Johnson Medical School in New Brunswick, N.J.
Dr. Anderson replied that the investigators attempted to exclude from DEFINITE any patients with myocarditis or other reversible causes of NIDCM, although that can be difficult. He added that the ejection fraction data are still being processed.
But even if it turns out many of these patients have a self-limited, reversible cardiomyopathy, the challenge will be to protect them from arrhythmic death during those initial months of high vulnerability.