Circulation: ICDs can lower risk of death in older heart patients

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Implantable cardioverter defibrillators (ICDs) can improve survival in patients with heart damage—even those in their 70s—according to research published Jan. 7 in Circulation: Cardiovascular Quality and Outcomes.

Implanted ICDs reduced the risk of dying by 30 percent in patients younger than 65 years old, 65 to 74, and 75 and older, said Paul Chan, MD, lead author of the study and assistant professor at the Mid-America Heart Institute and the University of Missouri in Kansas City.

This primary prevention study recruited 986 consecutive patients who had diminished left ventricular function—the pumping chamber of the heart was functioning at no more than 35 percent of capacity. Patients were treated from March 2001 though June 2005 and followed through March 2007.

The researchers compared outcomes of 500 patients who received ICDs to those who did not receive the devices. The median age of patients was 67, which was about seven years older than participants in an earlier study that investigated the use of ICDs in patients with heart failure (the SCD-HeFT trial) and about three years older than participants in a study that reported on the use of ICDs in patients who had heart attacks (the MADIT-2 trial).

“We sought to determine the effectiveness of ICDs in real-world patients who are older and have multiple co-existing illnesses,” Chan said.

Overall, Chan and colleagues found that 238 deaths occurred; 26.7 percent in the non-ICD group and 21.6 percent in the ICD group. Of these, 116 were attributed to arrhythmia; 13.7 percent in the non-ICD group and 9.8 percent in the ICD group.

“The ICD reduced all-cause mortality by 30 percent compared with patients who didn't receive ICDs," Chan said. "The use of ICDs in general practice reduced mortality similar to the levels seen in clinical trials. And, the use of ICDs in older patients and patients with comorbidities reduced mortality both in relative and absolute terms."

When researchers studied patients age 75 or older, they found that the level of survival benefit remained intact. But the benefit diminished when age was combined with multiple disease conditions.

The caveat, Chan said, was that "cost effectiveness estimates for ICD therapy in this study population depended upon both the degree and the number of comorbidities." Chan and his colleagues also reported that cost-effectiveness estimates for the use of ICD therapy by age and comorbidity subgroups.

The study was limited because of the relatively few patients in their 80s. “I feel comfortable applying the findings to septuagenarians, but we continue to have limited data on ICD use among octogenarians,” Chan said.