Medtronic Micra - The World's Smallest Pacemaker Begins Clinical Trials

 It's not uncommon to see disruptive technologies coming from startups and smaller businesses. What's more rare is seeing a Fortune 150 company deliberately disrupt itself as Medtronic is doing with its Micra Transcatheter Pacing System (TPS). The device, which the company boasts as the world's smallest pacemaker, is the result of over seven years of internal R&D and development at Medtronic. Using a term the company dubs “deep miniaturization” the Micra TPS is 90% smaller than the traditional pacemaker – bringing the size from 10 cc to 1 cc, comparable to a large vitamin pill.

“We really challenged the R&D organization to come up more disruptive things,” says Pat Mackin, president of the Cardiac Rhythm Disease Management business and senior vice president at Medtronic. “In pacing, the market is really fairly flat. We're getting some unit growth, but the prices are offsetting that. The old model of just adding another bell or whistle wasn't really having an impact on the marketplace. So we decided to go much more aggressive on making a change where you could get a step function change in outcomes.”

The Micra is a self-contained system, encapsulated in a single unit that goes directly into the heart. There's no external power source to be implanted and no lead wires. “Pacing is a very reliable therapy, but there are some complications from a traditional pacing system,” Mackin says. “You can get an infection from the generator, the lead wire can pop through and perforate a lung, the lead can come lose or break. The procedure is fairly benign and the complications are fairly low but still in the 3-4% range when you add all those things together. We think this new Micra system can eliminate a lot of those things.”

The device also eliminates the need for an incision and is implanted via a transcatheter procedure through the femoral vein in the groin - similar to a stent or percutaneous valve. “We go through the venous system, not the arterial system,” Mackin says. This delivery method also allows physicians a lot of control when placing the device. The Micra can be recaptured and repositioned during implantation and up to three to four weeks following the initial procedure before it becomes fully fixated in the body. Once implanted, Medtronic hopes the device's battery will allow it to last 10 years on average.

 At the time of writing four patients have been implanted with the Micra along with numerous animal and cadaver studies. Medtronic is currently beginning a single-arm, multi-center global clinical trial to test the safety and efficacy of the Micra. The study is recruiting 780 patients with the hope of enrolling 720 and will take place in 18 countries across 50 centers, 25 of which are in the United States. Mackin explains the study design is part of a company strategy to achieve regulatory approval in as many markets as possible as quickly as possible. “We need to meet the regulatory and clinical requirements of a number of geographies around the world. We're looking at one big global trial so that we really can have a comprehensive program that will meet the regulatory requirements of all the bodies that we work with.”

The Micra is a VVIR pacemaker, meaning it can regulate its rate to adapt to conditions such as physical exercise, but it can only be placed in a single chamber of the heart. As such, Mackin says the Micra is only appropriate for a specific type of patient. “This is for patients who have class I (low) or class II (moderate) indications for a pacemaker. So for someone who needs a dual chamber pacemaker this will not be for them,” he says.

Medtronic expects initial study results from the first 60 patients enrolled in the trial, followed up to three months, in the second half of 2014.

-Chris Wiltz, Associate Editor, MD+DI
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