An observational cohort study found that Medicare patients had a high rate of device-related complications and reoperations for other causes following implantation with implantable cardioverter-defibrillators (ICDs).

Lead researcher Isuru Ranasinghe, MBChB, MMed, PhD, of the Queen Elizabeth hospital in Australia, and colleagues published their findings online in the Annals of Internal Medicine on May 3.

Previous research showed that four to 11 percent of new ICD implantations resulted in hematoma formation, device malfunction, lead problems and other early complications, according to the researchers.

For this long-term analysis, they analyzed 114,484 patients from the National Cardiovascular Data Registry’s ICD registry who received an ICD for the first time from January 1, 2006, through March 31, 2010, at 1,437 hospitals in the U.S.

The patients were all at least 65 years old and had fee-for-service Medicare coverage. Of the patients, 19.8 percent received a single-chamber ICD, 41.3 percent received a dual-chamber ICD and 38.9 percent received cardiac resynchronization therapy with a defibrillator (CRT-D).

The researchers obtained long-term data on complications and reoperations by linking registry records with Medicare files that contained claims for inpatient admissions and outpatient procedures.

The mean age of patients was 74.8 years old, while 72.4 percent were male and 87.8 percent were white. In addition, 79.3 percent had a prior diagnosis of heart failure, 54.7 percent had prior New York Heart Association class III or IV heart failure, 79.1 percent had a left ventricular ejection fraction of less than 0.35 and 35.2 percent had prior sustained or nonsustained ventricular tachycardia.

After a median follow-up period of 2.7 years, 35 percent of patients died, which represented 12.6 deaths per 100 patient-years of follow-up. When accounting for the risk for death, the researchers found there were 6.1 ICD-related complications per 100 patient-years that required reoperation or hospitalization, including 2.6 that required an operation and 3.5 that required a hospitalization only.

In addition, the rate of mechanical complications (2.7 per 100 patient-years) was larger than the rate of device infection (0.80 per 100 patient-years). There were also 3.9 reoperations per 100 patient-years for reasons other than complications.

The following patient characteristics were associated with increased risks for ICD-related complications: younger age at implantation (65 to 69 years old versus older than 85), receipt of a CRT-D device versus a single-chamber device, female sex and black race.

The researchers cited a few limitations of the study, including that they used Medicare claims data, which lacked the complexity of clinical information compared with extracting data from clinical records. They also only included patients who were at least 65 years old and had Medicare coverage, so the results may not be generalizable to other patient populations. In addition, they did not count sudden cardiac death in the community due to the ICD itself before hospitalization as a complication.

Further, they did not distinguish device upgrades from generator replacements and did not distinguish generator replacements due to premature versus normal battery depletion. They also could not compare long-term nonfatal outcomes between device manufacturers.

“Long-term risks of ICD implantation and strategies to reduce them, such as by device selection, should be actively considered in the decision-making process before implantation,” the researchers wrote.