CardioMEMS New tool in monitoring pulmonary artery pressure

Winter Haven resident Glenda Johns’ battle with heart failure — marked by increasing weakness and frequent hospital stays  —  is a textbook case of how the condition can consume patients’ lives.

“Every couple to three weeks, at least once a month, I was having to go to the emergency room,” she said. “I was taking my diuretics as directed but I was still having buildup of fluid. I would get to the point where I could hardly breathe.”

She had a pacemaker and defibrillator installed. For a while, she was on a cardiac Life Vest, a wearable defibrillator for patients at risk of sudden cardiac death.

Then, on one of her many hospital visits, Dr. Kollagunta Chandrasekhar told her about CardioMEMS, a pulmonary artery pressure sensor.

It uses a tiny pressure-sensing device inserted into the pulmonary artery, the artery carrying blood from the right ventricle of the heart to the lungs.  MEMS is an acronym for micro-electro-mechanical system.

Johns had hers installed June 2 in an outpatient procedure at Winter Haven Hospital. As of Sept. 14, she hadn’t needed a repeat hospitalization.

The device monitors her pulmonary artery pressure at her home, detecting changes that can signal worsening heart failure. 

“The advantage of this is that you’re getting the information a good two to three weeks before they’re getting symptoms,” Chandrasekhar said.

That gives him a greater window of opportunity to suggest actions, such as drinking less fluids or taking a diuretic to increase urination, that can get her pressure to a better state, reducing the likelihood of a hospital stay.

Hemodynamic effects of heart failure, changes in cardiovascular function like artery pressure, occur before symptoms like swelling appear.

Being able to detect changes in pulmonary artery pressure  makes it less likely doctors will wait for visible signs like weight gain or increased shortness of breath before they adjust treatment.

“There have been multiple studies that have shown, despite our best efforts monitoring weight, medication compliance, (liquid) intake and output, physical exam and chest X-ray findings, that we fall short in our ability to keep our patients from becoming congested and landing in our emergency rooms and hospitals,” said Dr. Debbie Rinde-Hoffman, medical director for advanced heart failure at Tampa General Hospital.

As patients require hospitalization, she said, their prognosis changes for the worse.

If a patient keeps retaining fluid, necessitating taking a diuretic to eliminate the fluid, they become more resistant to the drug, leading to more and more medication,  Chandrasekhar said, adding, “The more medication they take, the less they like it.”

Which can lead them to be less compliant in taking their medicine, increasing risk of future complications.

Clinical trials of CardioMEMS found its monitoring reduced hospitalizations for patients who meet the criteria for it, adding a new dimension of treatment.

The device has been effective for both types of heart failure, those with a weak heart and those with a stiff heart, Rinde-Hoffman said, adding that the latter group “do not have great options for medical therapy.”

Slow response by government and private insurance delayed many hospitals’ ability to provide CardioMEMS, which the Food and Drug Administration approved for marketing in 2014..

Chandrasekhar had been waiting impatiently to offer the device at WHH. Johns’ device was the second he implanted there.

Although he was able to provide it earlier for a handful of patients at AdventHealth Lake Wales, Chandrasekhar said, limitations imposed by insurance companies processing Medicare claims caused a long delay.

Tampa General Hospital faced a similar delay, but it was able to enroll in a clinical trial that sought to expand the boundaries of who qualifies for CardioMEMS. That let more patients get the device there.

Its Medicare intermediary, First Coast, denied payment for the device until July 2020, Rinde-Hoffman said.

She said they continue having some difficulty with non-governmental insurers.

More than 20,000 Abbott CardioMEMS had been implanted worldwide as of December 2020, however, said a spokesperson for Abbott.

The chief eligibility requirements are having been hospitalized for heart failure in the past year and having Class III Heart Failure on the New York Heart Association classification system.

Class III is people like Johns, 77, who have marked limitation in their physical activity.  She’s been fortunate to have two sisters in Polk County, Bobbie Ellis and Shirley Cannon, to give her support.

“There is plenty of data to support hemodynamic monitoring and remote monitoring is the wave of the future,” Rinde-Hoffman said.

“(A) personalized approach to take care of the patient in their home, as much as it is safe, will be aided by additional methodologies, and this is clearly one of them."

More on how the CardioMEMS heart failure system works:

The pressure-sensing device is inserted into the pulmonary artery. This is done through a small tube or catheter with X-ray guidance, a procedure typically taking less than 45 minutes, Rinde-Hoffman said.

Each patient has a home electronic unit, about the size of a queen-sized pillow, on which the patient lies for pulmonary artery pressure readings. 

The system sends these readings daily to the patient’s heart-failure doctor or team.

“Every night, they have this pillow they lie on for 10 minutes or so,” Chandrasekhar said. “It records the numbers. …I look at (the data) once a week. I can see what the trend has been.”

WHAT THE STUDIES DETERMINED

The CHAMPION trial whose results published in 2014 found heart-failure management based on using CardioMEMS monitoring significantly reduced hospital admissions of heart-failure patients.

(CHAMPION stands for CardioMEMS Heart Sensor Allows Monitoring of Pressure to Improve Outcomes in NYHA Class III Heart Failure Patients.)

A later study, the CardioMEMS Post-Approval Study, looked at the effectiveness and safety of the device for that category of patient being treated in routine clinical practice. It involved 1,200 patients at 104 centers nationwide, including Florida Hospital Transplant Institute, who got the device implanted between Sept. 1, 2014 and Oct. 11, 2017.

That study demonstrated pulmonary artery pressure-guided therapy for heart failure was associated with lower pulmonary artery pressure, lower rates of hospitalization related to heart failure and lower hospitalization for all causes in those study patients.

Results were consistent across subgroups defined by categories like race, sex, cause of heart failure and whether or not the patients had an implantable cardiac defibrillator, according to a 2020 article in Circulation Heart Failure.

Another study, GUIDE-HF, sought to find out whether patient eligibility for Cardio-MEMS should be broadened. Its results weren’t as clear.

 It had positive results in patients who completed their 12-month study before COVID-19 arrived, Rinde-Hoffman said, but the impact of COVID then created “confounding issues” like less eating out, more self-care and less reporting to the hospital. She was involved in the GUIDE-HF trial.

Encouraged by trial data adjusted for COVID-19, Abbott continues seeking expanded guidelines for when using CardioMEMS is appropriate.

Robin Williams Adams can be reached at robinwadams99@yahoo.com