Medtronic’s (NYSE:MDT) Micra device is likely the cardiac rhythm management pioneer’s most-tested pacemaker, according to the senior principal scientist who led the team that developed the leadless pacemaker.
Some 140 patients in a trial were implanted with the micro-sized pacing device without any unanticipated events, up from the 96 patients reported at the Heart Rhythm Society’s annual meeting last month, senior principal scientist Matthew Bonner told the Minneapolis Star-Tribune.
"With anything novel, certainly there are potential risks. But now, first of all we did a tremendous amount of study on this device before we went to people. It was probably analyzed and tested more than any pacemaker we’ve put out," Bonner told the newspaper. "And there were no unanticipated events. From that standpoint, there could have been risks, but we haven’t seen any yet. It looks like it is going to achieve our goals of performing the way a normal pacemaker does, but in a much smaller package and with fewer complications."
At HRS 2015 last month in Boston, Medtronic reported a 100% successful implantation rate for the 1st 96 patients in a trial of the device that’s slated to add another 700+ patients.
Eight serious adverse events in 7 patients were recorded, Medtronic said at the time, most likely due to mechanical stimulation by the catheter that delivers the Micra to the heart. One patient suffered pericardial effusion without tamponade and had a myocardial infarction, but lived, the company added.
Bonner said it’s more difficult to prove safety than to develop an innovative new concept.
"I don’t think it’s tough to innovate. I think it’s tough to prove that the devices are as safe as they need to be. And that was 1 thing here. We spent a lot of the energy proving it was safe, proving it would do what it does," he told the paper. "One of the big issues starting out is [that] current pacemakers are quite reliable, so the bar for maintaining that reliability was pretty high. I think that’s why we were given the resources to do all the testing we did, so that when we went to the 1st human implant, we were pretty confident that it would do what was expected."
There are 2 other major players in the CRM space, St. Jude Medical (NYSE:STJ) and Boston Scientific (NYSE:BSX). Earlier this year, St. Jude paused enrollment in a European trial of its Micra-competing Nanostim device while it evaluates a series of adverse events, including perforation of the heart and dislodgement of the device. Trial enrollment for the Nanostim was paused once before in April 2014, after researchers reported 6 instances of perforation, including 2 patient deaths, out of more than 200 implants.
Boston is developing its own leadless pacer to complement its S-ICD line, Dr. Ken Stein told MassDevice.com at HRS 2015. Although it laid claim to the 1st leadless pacer when it acquired Cameron Health’s S-ICD for up to $1.35 billion in June 2012, that device actually uses leads implanted in a surgically created channel along the patient’s chest. Medtronic’s Micra and St. Jude’s Nanostim devices, in contrast, are designed to be implanted directly in the heart via catheter. The new Boston Scientific device would also use transcatheter delivery, Stein said.