LEADLESS II IDE Trial Supports St. Jude Medical's Nanostim Leadless Pacemaker

September 4, 2015—St. Jude Medical, Inc. announced primary results from the LEADLESS II study that confirm the positive benefits of the company’s Nanostim leadless pacemaker for patients in need of a single-chamber ventricular pacemaker. The study also demonstrated the Nanostim leadless pacemaker’s longer-term retrievability and the device battery’s significant projected longevity. The device received European CE Mark approval in October 2013.

The LEADLESS II study was presented during a Hot Line session at the ESC Congress 2015, held August 29 to September 2 in London, United Kingdom. LEADLESS II Principal Investigator Vivek Reddy, MD, et al published the findings online ahead of print in The New England Journal of Medicine. 

The LEADLESS II investigational device exemption study enrolled 526 patients at 56 centers across the United States, Canada, and Australia. After 6 months, the trial met both endpoints for primary effectiveness (appropriate pacing and sensing) and safety (freedom from serious adverse device effects). The trial also demonstrated the Nanostim leadless pacemaker’s retrievability and projected longevity.

According to the company, retrievability is a core benefit of the Nanostim leadless pacemaker. Over the duration of the study, LEADLESS II demonstrated that retrieval of the implanted Nanostim was successful in 100% of patients requiring retrieval without any associated complications. For longevity, Nanostim’s battery could be projected to last an average of 15 years, and possibly projected as high as 21 years, depending on pacing needs. The longevity of the Nanostim device has been estimated to be 9.8 years at 100% pacing.

St. Jude Medical noted that in the LEADLESS II study, there were 22 serious adverse device effects observed over 6 months, including cardiac perforation, device dislodgement, and elevated pacing capture thresholds at rates of 1.3%, 1.7%, and 1.3%, respectively, which is consistent with traditional pacemakers.

In the company’s press release, Dr. Reddy commented, “We are excited to share the results of LEADLESS II, which continues to grow the body of evidence supporting the safety and efficacy of the Nanostim leadless pacemaker. The LEADLESS II study results are advancing our understanding of leadless pacing technology and highlighting a number of benefits for physicians seeking a minimally invasive, leadless option for patients in need of permanent, single-chamber pacing therapy.” Dr. Reddy is Director of Electrophysiology at The Mount Sinai Hospital in New York, New York.

The Nanostim leadless pacemaker is designed to be implanted minimally invasively via the femoral vein. The system is implanted with a delivery system catheter and an 18-F introducer. The device is entirely self-contained. It is approximately 1.5 inches long and < 6 mm in diameter, which is < 10% of the size of a conventional pacemaker. The Nanostim leadless pacemaker eliminates the surgical pocket and leads, which represent the most vulnerable component of traditional pacing systems.