Following a myocardial infarction (MI), only one in 10 patients age 65 or older with an ejection fraction of 35 percent or less had an implantable cardioverter-defibrillator (ICD) inserted within one year, and on average, patients who received an ICD had a significantly lower mortality rate than those who did not – 15.3 vs. 26.4 events per 100 patient-years, according to a study published June 23 in the Journal of the American Medical Association.

Using data from the ACC’s ACTION Registry-GWTG linked with Medicare data, researchers assessed records from 10,318 patients at 242 hospitals between January 2, 2007, and September 30, 2010. The median age of patients was 78, and the majority (75 percent) underwent in-hospital revascularization.   

Results showed that cumulative ICD implantation rate within one year of the cardiac event was 8.1 percent, and median time from admission to implantation was 137 days. For patients who had undergone revascularization, the timeframe was 115 days.  

Based on their findings, the authors identified patient factors associated with a greater likelihood of ICD implantation within one year of the MI: younger, male patients who had prior coronary artery bypass graft procedures, larger infarcts, in-hospital cardiogenic shock, and cardiology follow-up within two weeks after hospital discharge. Those patients with a lower likelihood of ICD implantation were older, female, and had end-stage renal disease.    

Researchers also found significant variation in hospital ICD implantation rates. After adjusting for differences in the patient mix across hospitals, the study showed that among 242 hospitals, the median estimated one-year ICD implantation rate was 7.4 percent. Patients in hospitals in the 90th percentile of one-year ICD implantation (11.5 percent) were 2.4-fold more likely to receive an ICD than hospitals in the 10th percentile (4.8 percent).   

The authors conclude that moving forward, “additional research is needed to determine evidence-based approaches to increase ICD implantation among eligible patients.”

Sean Pokorney, MD, MBA, a cardiology fellow in the Division of Cardiology at Duke University Medical Center and the study’s lead author, notes that the study’s findings are surprising and raise “concerns about gaps in care that occur during the transition from inpatient care to outpatient care.” He adds that the study “should raise awareness of the need to be vigilant about identifying patients who are candidates for primary prevention ICDs.”

In an accompanying editorial, Robert G. Hauser, MD, FACC, a cardiologist with the Minneapolis Heart Institute at Abbott Northwestern Hospital, agrees that it is “concerning that so few potentially ICD-eligible patients are undergoing implantation, especially considering that ICDs significantly improve survival.” He suggests that the reason for the problem is the fragmented health care system in which “overly burdened primary care physicians are expected to connect all the clinical and diagnostic information without the essential tools and necessary facts.”

“Even though the use of ICDs for primary prevention may not seem to make as much sense for an 80-year-old patient as it does for a patient in his or her 50s or 60s,” continues Hauser, “an older patient at risk for sudden cardiac death should have the same opportunity to choose potentially lifesaving therapy. [This study] can help physicians and their patients be better informed during discussions about the risks and benefits of ICDs in older persons.”  

Keywords: Ambulatory Care, Coronary Artery Bypass, Death, Sudden, Cardiac, Defibrillators, Implantable, Follow-Up Studies, Inpatients, Kidney Failure, Chronic, Medicare, Myocardial Infarction, Physicians, Physicians, Primary Care, Primary Prevention, Registries, Risk Assessment, Shock, Cardiogenic

< Back to Listings