CMS expands ICD coverage criteria

CMS has opened the door to wider use of ICD therapy; cardiologists should use this powerful tool wisely.

In January, the Center for Medicare Services issued new eligibility for insertion of implantable cardioverter defibrillators. The new guidelines recognize the expanding role of ICDs in patient management and clarified many issues for the electrophysiology community.

Implantable defibrillators were first introduced into clinical practice in 1980. At first they were used only in patients with recurrent cardiac arrest who were resistant to therapy with antiarrhythmic drugs.

As ICD technology advanced, the devices became smaller, better tolerated by patients and more capable of effectively managing both ventricular tachycardia and ventricular fibrillation. During their first 15 years of use, however, claims of efficacy were based mostly on observational case series or historical controls.

John P. DiMarco, MD, PhD

Over the last decade, a series of controlled randomized trials have demonstrated that ICD therapy is effective and well-tolerated for both secondary and primary prevention of sudden cardiac death.

Prevention trials

The three major secondary prevention trials — AVID, CIDS and CASH — enrolled survivors of a ventricular arrthythmia with any cardiac diagnosis. In contrast, the early randomized primary prevention trials concentrated on patients with coronary artery disease, prior MI and low ejection fractions. In an evidence-based approach, CMS, with a few exceptions, limited coverage for ICD therapy for primary therapy to such patients.

The Defibrillator in Nonischemic Cardiomyopathy Treatment Evaluation (DEFINITE) study and the Sudden Cardiac Death — Heart Failure Trial (SCD-HeFT), however, provided data that showed ICDs to be at least equally effective in patients with nonischemic cardiomyopathies.

SCD-HeFT, the largest defibrillator trial reported so far, included over 2,500 patients with New York Heart Association Class II and Class III heart failure with ejection fractions <35%.

Patients with both ischemic and nonischemic cardiomyopathy were included. SCD-HeFT demonstrated a reduction in the mortality hazard ratio of 0.77 with little difference between these two groups.

When the SCD-HeFT data were first presented at the American College of Cardiology Scientific Session in March 2004, they created a large gap between trial data and accepted CMS coverage criteria.

A new set of guidelines

This situation led to considerable pressure on CMS to alter its guidelines. CMS waited until the SCD-HeFT data were finally published this January and then rapidly issued a new set of guidelines. The significant additions in the new guidelines include patients with nonischemic dilated cardiomyopathy with Class II and Class III heart failure.

The new rules also eliminated the previous requirement of a QRS duration >120 msec in patients with ischemic cardiomyopathy and ejection fractions <30%. These revised guidelines will greatly enlarge the pool of potential candidates for ICD therapy.

There are two important restrictions in the new ICD guidelines that still require clarification. Two large randomized trials of ICD therapy have not shown benefit.

The Coronary Artery Bypass Graft Trial (CABG-Patch) did not show benefit in patients who received an ICD at the time of surgical coronary revascularization. The Defibrillators in Acute Myocardial Infarction Trial (DINAMIT) also showed no benefit when ICDs were used in patients within 40 days of acute MI.

Based on the results of these two trials, the CMS guidelines now prohibit ICD use for primary prevention in patients with recent myocardial revascularization, this includes percutaneous revascularization, and in patients who had an acute MI within 30 days.

These restrictions may lead to difficult decision-making when high-risk patients are identified soon after either revascularization or an MI. In such patients, however, it still should be possible to use an old criterion, induction of ventricular tachycardia during programmed stimulation, even though this approach is not as firmly supported by trial data.

The CMS guidelines also provided for creation of a nationwide database of ICD usage. Implanting physicians now fill out a questionnaire that will provide data for subsequent analysis.

CMS also requires written justification for the use of ICDs other than single lead, shock-only devices for primary prevention.

Centers are required to provide written justification including patient characteristics justifying the use of more complex devices. It remains to be seen if this registry will be useful.

CMS has opened the door to wider use of ICD therapy. It remains for cardiologists to use this powerful tool wisely.

John P. DiMarco, MD, PhD, is professor of medicine and director, cardiac electrophysiology laboratory, cardiovascular division, University of Virginia Health System. He is a board member of Cardiology Today’s Electrophysiology and Arrhythmia Disorders section.