BOSTON — An investigative small-diameter defibrillation lead for implantable cardioverter-defibrillators has exceeded its safety and efficacy expectations in a pivotal clinical trial.
The LEADR trial implanted OmniaSecure leads in 643 patients. It found that almost 98% of the experimental leads were successfully implanted, and 99.5% were placed precisely in the desired location in the right ventricle.
Around 97% of patients had no lead-related major complications in the 12 months of the study, and none of the leads fractured during the study period, George H. Crossley III, MD, of Vanderbilt University Medical Center in Nashville, Tennessee, reported at the Heart Rhythm Society (HRS) 2024 meeting. The results were published simultaneously in the journal Heart Rhythm.
"The big point here is that this is a new approach to creating a new defibrillator lead by taking a really robust pacemaker lead and changing the insulation," Crossley said in an interview. Those changes make the catheter more flexible so the operator can deliver the lead faster and with more precise placement, he said.
The OmniaSecure lead, made by medical device maker Medtronic, is compatible with many commercially available catheters. It's based on Medtronic's SelectSecure Model 3830 pacing lead, which has been in use since 2003. Both leads have a cable-based tip conductor that reduces the lead diameter while maintaining flexibility and tensile strength, said Crossley.
OmniaSecure has a thickened layer of polyurethane insulation on the high-voltage conductor and a larger 4.7-French lead than the SelectSecure's 4.1-French lead. "So this is really an upsized 3830," Crossley said.
Trial Results
In addition to successful and accurate placements, "the observed defibrillation efficacy at implant was 97.5%, so the primary efficacy threshold was exceeded," said Crossley.
Antitachycardia pacing efficacy was high, Crossley noted, at 74.9% (359 of 479 episodes), while the ambulatory shock efficacy was 95% (95 of 100 episodes).
"The inappropriate shock rate at 12 months was low," he added. The single-chamber rate was 2.7%, and the dual-chamber/cardiac resynchronization therapy rate was 2.8%.
"The other and possibly the most unique part of this study was the engineering analysis of lead failure, which was based upon the techniques that were developed in response to the Fidelis lead failure," Crossley said, referring to the Sprint Fidelis leads that were pulled from the market in 2007 after reports surfaced of high failure rates.
OmniaSecure was developed and validated using leads with known clinical performance, with Fidelis as a poorly performing control and Quattro as a well-performing control, he said. "These data were then used to drive the bench-top testing," he said, which indicated a high likelihood of success with the OmniaSecure, which has now been borne out in the clinical trial.
The Case for Vigilance
Robert Hauser, MD, of the Minneapolis Heart Institute Foundation, Minneapolis, said the OmniaSecure is a "substantial improvement" over the SelectSecure lead. "The lead has tremendous potential for versatility; not just the defibrillator lead that you put in the right ventricle, but it's a defibrillator lead that you can do other things with," he said.
But he also raised one potential issue: The polyurethane insulation will exhibit some environmental stress cracking over time. The greater thickness on its sleeve vs the SelectSecure, however, should help avoid any potential issues. "But you [should] keep your eyes open," to the possibility, Hauser said, by doing routine fibrillation threshold testing.
"While some implanting physicians believe that fibrillation threshold testing is not necessary at implant, many of us believe it should be done routinely regardless of lead model," he said. "It certainly should be done during OmniaSecure implantation."