After CMS received public comments, the agency announced on Jan. 18 that it is finalizing its proposal to cover leadless pacemakers.

CMS plans on covering leadless pacemakers when procedures are performed in FDA-approved studies as well as in prospective longitudinal studies that meet certain criteria.

In April, the FDA approved the Micra Transcatheter Pacing System (Medtronic), which is still the only FDA-approved leadless pacemaker. That approval was based on results of a single-arm study that enrolled 725 patients at 56 centers in 19 countries. Results were published in November 2015 in the New England Journal of Medicine and simultaneously presented at the American Heart Association Scientific Sessions.

St. Jude Medical is also developing the Nanostim leadless pacemaker, which is not yet FDA-approved. The company is evaluating the device in the Leadless II study.

In October, St. Jude Medical temporarily halted enrollment in the Leadless II trial after discovering problems with electronic data reporting from 0.5 percent of the devices, according to the Minneapolis Star Tribune.

CMS said leadless pacemakers might provide therapy for fewer than 20 percent of patients requiring a pacemaker. The agency added that leadless pacemakers are typically used in patients with atrial fibrillation and bradycardia or in patients who only need infrequent pacing.

CMS also mentioned that evidence is lacking on whether leadless pacemakers reduce symptoms and syncope and improve survival. In addition, there is no data for chronic complications and long-term performance.

“The available evidence is insufficient to confidently determine whether leadless pacemakers improve health outcomes in real world practice outside the controlled study environment,” the researchers wrote. “Evidence-based guidelines and professional society recommendations have also not specifically addressed leadless technologies to date.”

CMS opened a National Coverage Analysis for leadless pacemakers on May 18, 2016, and initiated a 30-day public comment period. The agency then posted a proposed decision memorandum on Nov. 14, 2016, and opened a second 30-day public comment period.

The CMS document noted that leadless pacemakers are delivered via catheters to the right ventricle of the heart and that they function similarly to other transvenous single-chamber ventricular pacemakers. The agency added that the devices have not been tested in real-world settings. The FDA has also mandated postmarket studies for the Micra device.

“CMS believes that the evidence is promising and sufficient for coverage of leadless pacemakers when furnished in CMS-approved studies under [Coverage with Evidence Development,” the researchers wrote. “CMS believes that the available evidence is not sufficient to determine long term health outcomes or to identify the characteristics of the patient, practitioner or facility that predict which beneficiaries are more likely to experience overall benefit or harm from leadless pacemakers. Significant questions remain regarding the potential for deterioration in left ventricular function and other long term outcomes, as well as device longevity.”