Features November 2018 Issue

Leadless Pacemakers Prove Unlikely to Cause Infection

Eliminating leads and pockets has stopped the vast majority of infections that are common with traditional pacemakers.

Each year, about 1 million people in this country receive a pacemaker to regulate their slowing heart rate. These pacemakers are implanted in a pocket of tissue under the skin and send electrical pulses down a lead (wire) inserted into the heart muscle. Pockets can be a source of infection, which then spreads into the bloodstream via the lead and can infect the heart.

Over a four-year period, about 12 percent of pacemaker patients experience infection or other complication requiring surgery or hospitalization.

Leadless pacemakers were introduced in 2014 with the hopes of eliminating these problems. The tiny, self-contained powerhouses are inserted directly into the heart through a catheter. After comparing 718 of patients with leadless pacemakers and 1,436 patients with conventional pacemakers, a Cleveland Clinic-led study confirmed that the tiny devices deliver.

nanostim

© Image courtesy of Nanostim, Inc.

The Nanostim (top left) is as powerful as a larger, traditional pacemaker (top right), but safer.

"By eliminating leads and pockets, leadless pacemakers have largely eliminated infection, one of the most serious and frustrating complications associated with pacemakers," says Daniel Cantillon, MD, research director for Cardiac Electrophysiology and Pacing at Cleveland Clinic and organizer of the multi-institutional study.

Fewer Complications

The study compared outcomes from patients who had received the Nanostim leadless pacemaker through the LEADLESS II trial with those who received conventional pacemakers.

One month after implantation, only 5.8 percent of patients who received the Nanostim had experienced complications, versus 9.4 percent with traditional pacemakers.

Between one month and 18 months, only 0.56 percent of Nanostim patients experienced complications that affected 4.94 percent of patients with a conventional pacemaker.

Nanostim patients suffered no infections or complications and no electrode dislodgements during the 18-month study. On the other hand, nearly 6 percent of those who received a conventional pacemaker experienced one of these events.

Not Perfect Yet

The leadless pacemaker was not entirely problem-free, however. It was more likely than the traditional pacemaker to cause bleeding around the heart-an uncommon but serious problem called pericardial effusion.

"Leadless pacemakers are a developing technology. We expect complications like this to continue declining as the technology improves and physicians gain experience implanting these devices," says Dr. Cantillon.

Why Leadless Is Important

Over time, leads become embedded in scar tissue that can adhere to nearby blood vessels. The area becomes calcified, making lead removal difficult and risky. For this reason, some physicians simply leave unwanted leads in the body when a new pacemaker or lead is needed.

When a lead becomes infected and must be removed, there is no substitute for expertise and experience. Any patient with a lead that has been in place more than five years or has undergone previous heart surgery is at increased risk for problems when extraction is attempted.

Since 2014, Cleveland Clinic electrophysiologists have performed lead extractions on high-risk patients in a hybrid operating room with a cardiac surgeon and cardiac anesthesiologist standing by. This minimizes the time needed to rescue the patient with surgery, should it become necessary.

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