BOSTON—After a mean follow-up of 7.5 years, electrical failure occurred in 5.9 percent of patients using the Riata lead, according to a prospective, observational study of the Riata leads under advisory in Canada. In addition, 7.4 percent of patients had electrical failure or cable externalization.

For the 8-French lead, the 10-year failure rate was 5.9 percent, while the eight-year failure rate for the 7-French lead was 5.1 percent. There was no statistically significant difference between the two models.

Lead researcher Ratika Parkash, MD, of Dalhousie University in Halifax, Canada, presented results of the study on May 15 during a late-breaking clinical trials session at Heart Rhythm 2015.

“Given this data, isolated lead revision or extraction due to advisory is not warranted,” Parkash said.

The CREDO (Canadian Registry of Cardiac Implantable Electronic Device Outcomes) study enrolled 2,707 patients at 15 cardiac implantable electronic device and follow-up centers in Canada.

Researchers evaluated 59.7 percent of the patients in Canada with a Riata lead model under advisory. Of the leads examined, 70.2 percent were 8-French leads and 29.8 percent were 7-French leads. In 2011, St. Jude Medical recalled its Riata leads in the U.S. because of cable externalization and insulation abrasion.

At baseline, the mean age was 63 years old, and more than 80 percent of patients were men. The mean follow-up was 7.5 months.

The most common reason for lead revision was for electrical abnormalities (42.1 percent of cases), followed by lead dislodgement (18.3 percent), infection (12.4 percent) and cable externalization (11.6 percent).

The rate of cable externalization was 7.4 percent for the 8-French lead and 4.9 percent for the 7-French lead, which was not a statistically significant difference. Most of the cases of cable externalization occurred after six years for both models.

Cable externalization with electrical failure occurred in 10.1 percent of patients, including 9.4 percent with the 8-French lead and 13.3 percent with the 7-French lead.

Predictors of electrical lead failure included younger age, secondary indication for implantable cardioverter-defibrillator, higher left ventricular ejection fraction and more mild heart failure.

“It’s difficult to uncouple the fact that younger patients live longer and may have a higher ability to experience a lead failure compared to older patients,” Parkash said. “But in the multivariate model, it still comes out, as does the ejection fraction. We’ve seen this in other cohorts… It may well be that those (younger) patients are more active, are moving more and are more prone to lead failure.”

There were no implant characteristics that were associated with electrical failure, including the lead approach or lead type.

Periprocedural complications with revision of leads were found in 6.3 percent of patients, including 5.5 percent using the 8-French lead and 8.3 percent of patients using the 7-French lead.

One patient in each group died. Both deaths were due to sepsis after the lead revision and occurred in patients who did not undergo lead extraction. Parkash said another death was attributable to failed defibrillation due to lead malfunction.