Wireless Sensor Monitors Heart Failure Patients
Study Suggests Experimental Device May Cut Hospitalization Rate for People With Heat Failure
By Salynn Boyles
WebMD Health News
Reviewed by Louise Chang, MD
heart monitor graphic

Feb. 9, 2011 -- An implanted wireless monitoring device about the size of a paper clip reduced hospitalizations among heart failure patients by 39%, a study shows.

The experimental implant is designed to measure pressure in a pulmonary artery, which is a leading indicator of how well a patient’s heart failure is being managed with drugs.

The study is published in The Lancet.

Atlanta-based company CardioMEMS, which paid for the study, hopes to win FDA approval to market the device for use by patients with heart failure later this year.

Just as frequent blood sugar readings help with adjusting insulin for diabetes, the thinking is that closely monitoring pulmonary artery pressure can help adjust medications for heart failure patients.

As the researchers had hoped, study participants with the devices had fewer hospitalizations than those who got standard care, says study researcher William T. Abraham, MD, who directs the Ohio State University Medical Center’s division of cardiovascular medicine.

“We showed that by monitoring pressure precisely every day and adjusting medications to keep pressures in or near the normal range, patients felt better and spent less time in the hospital,” Abraham says.
Expensive Care for Heart Failure

About 5.8 million Americans have heart failure, at a cost to the nation of about $39 billion a year in health care services, medications, and lost productivity, according to the CDC.

Heart failure-related hospitalizations account for about half of that figure, Abraham tells WebMD.

The study included patients with moderate heart failure who had at least one prior hospital admission for heart failure. The patients were treated at 64 centers across the country.

About half the patients underwent a catheterization procedure to place the small wireless sensor in a pulmonary artery while the other half received standard medical care.

A special pillow containing an antenna simultaneously powers the sensor and takes a pressure reading via radio waves that are harmless to the patient, Abraham says.

Once a day, the patients lay on the pillow and pushed a button to turn the device on. The reading was then taken and sent through a wireless connection to a secure web site.

Doctors and nurses could also have the readings sent to their smart phones, and the device even alerts the provider when pressure readings indicate a problem.
No Batteries or Moving Parts

Over 15 months of use, 253 heart failure-related hospitalizations occurred in the 280 patients who did not have the devices vs.153 hospitalizations in the 270 patients who did get them.

One of the main advantages of the sensor is that it does not require batteries, Abraham says.

“There are no moving parts and nothing to wear out or replace,” he says.

The FDA failed to approve an earlier version of a wireless heart-monitoring device, made by the company Metronics. And efforts by another company to market a wireless cardiac device designed to monitor arrhythmia were also unsuccessful.

Abraham says the CardioMEMS device should cost between $10,000 and $20,000.

“When you consider that one heart failure hospitalization may cost in the neighborhood of $10,000 to $15,000 you can see that it makes economic sense in patients who are at risk for hospitalization,” he says.

Long Island Jewish Medical Center cardiologist Bruce Goldner, MD, calls the findings impressive. But he tells WebMD that he would like to see additional studies to confirm them with longer patient follow-up.

“These patients were followed for around 600 days and the major complication rate was low (1.4%),” he says. “But we can’t really say if more complications will be seen with longer-term use.”