Cardioverter Study DANISH Challenges Heart Failure Guidelines

Implantable cardioverter-defibrillators are not for all heart failure patients, researchers said today at the European Society of Cardiology’s ESC Congress 2016 in Rome, Italy.

In a study that was also published online today in the New England Journal of Medicine, Lars Kober, MD of Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark, found that placement of the devices in patients with non-ischemic systolic heart failure did not improve overall survival any better than usual clinical care.

The cardioverters did show a big benefit for some patients--they apparently saved their lives. The group in the study who had them had half the number of sudden cardiac death.

Known as the DANISH study, its findings sparked an immediate debate over whether the devices are currently over-used, since guidelines written by both the ESC and the American Heart Association endorse their implantation in these patients. In the study, 560 patients got usual care, including medications and 556 patients got a cardioverter.

For 58% of patients in both groups, care included cardiac resynchronization therapy (CRT).

The patients were followed a median five and half years.

During that time, 21.6% of the patients who were implanted died, though not necessarily of cardiac causes. The rate was only slightly higher, 23.4% in the control group.

To Kober, that was proof that physicians should not routinely use the devices on all patients with non-ischemic systolic heart failure.

But others suggested that the study design used the wrong primary endpoint, and said that measurement should have been the percentage of patients who died of sudden cardiac death.

Kober characterized the study findings as “neutral” but in answer to questions in a news conference said “We can speculate that another primary endpoint would have been positive.”

In an editorial accompanying the NEJM article, John McMurray, MD, of the University of Glasgow, UK, said treatment of heart disease has improved greatly since cardioverters became available, and that the patients in the trial were already getting effective care through drugs--including those who got the devices

“That there was no significant benefit with regard to overall mortality in the DANISH trial was a result of the low risk of sudden cardiac death among the patients included in the trial,” he wrote.