New Mesh Technology Helps Holds Down Infection Rates In Pacemakers | KERA News

New Mesh Technology Helps Holds Down Infection Rates In Pacemakers

Jul 29, 2019

About 250,000 people each year get pacemakers implanted to help maintain a steady heartbeat. Infection rates from the procedure are low in the U.S. But a simple mesh envelope is helping to reduce that rate further. 

The current infection rate in the U.S. from implanting cardiac electronic devices is about 1.2%. Modern precautions have kept that rate low. But with the population getting older, more people will need to get pacemakers or pacemaker defibrillators.

"A pacemaker battery lasts 10 years. So now they're having to get a battery change as they get older," said Dr. Hafiza Khan, a cardiologist with Baylor Scott White Heart Hospital in Plano. "So in 10 years you've got to do one battery change. Ten years later a second battery change. I've been in practice 18 years. I see patients who are on their third or fourth surgery. The more you do surgery on the same location, the increased risk of infection."

Khan was the hospital's investigator in a study of a simple solution to preventing infection: Implant the device in an absorbable, mesh envelope infused with antibiotics. The antibiotics absorb into the pocket, and the pouch dissolves away after about a week.

The FDA approved the envelope several years ago, but the study has confirmed the device significantly helps protect against infections.

"And now that we have that," said Dr. Khan, "I think that more doctors more hospitals more insurers are willing to pay for the little extra bit that this costs to prevent downstream high morbidity complication."

INTERVIEW HIGHLIGHTS:

What often causes the infection: "Usually the patient has a compromised immune system because they're a diabetic. They're on steroids. They've got kidney disease or heart failure. So anytime you cut the skin, bacteria can crawl into the pocket."

Common types of infections: "Staph infections, staph aureus.  Staph infections are serious and they're life threatening. You can get septic and these are people who need pacemakers or a defibrillator so they're not healthy necessarily to begin with."

About the envelope: "It's a mesh envelope made of an absorbable polymer. It's coated with two types of powerful antibiotics to fight staph infections: Rifampin and tetracycline. So before the doctor puts the device underneath the skin, they slip the device into the envelope and tuck it all into the pocket. The antibiotic diffuses into the pocket and kills staph aureus over seven days.  In about nine weeks, the whole envelope dissolves but there's no remnant or nothing residual left in the body. Staph infections tend to happen in the first four to six weeks when the skin is cotton. Things are fresh. So once you've made it past that initial hump you're home free."

How effective is the envelope? "There is a 60 percent reduction in minor infections little skin issues. But there is a 40 percent reduction in major infections major meaning otherwise the doctor would have had to take the whole kit and caboodle out. "

Origin of the envelope: "In the 1940s and 50s, pacemakers were huge and it would move in people's body. So Dr. Victor Parsonnet that invented an envelope or pouch to hold it up and to tack it down because the unit weighed a lot. Someone then took it to the next level. We don't need an envelope because devices are small and tiny. But what if we took the concept of the envelope and coated it with antibiotics. And that way we can prevent infections in the tissue. Taking a pill antibiotic diffuses all over, it doesn't go to that particular location, it can go anywhere."

RESOURCES:

About the Antibacterial Absorbable Envelope

WRAP-IT Study (https://www.medtronic.com/content/dam/medtronic-com/01_crhf/tyrx/wrap-it-study-summary.pdf)

Medtronic Tyrx Envelope Significantly Reduces Major Infections in Cardiac Implantable Device Patients

Cost-effectiveness of TYRX

Cardiac implantable electronic device (CIED) infections are expensive and associated with prolonged hospitalisation: UK Retrospective Observational Study

Absorbable antibiotic envelope can significantly cut cardiac device infection