Posted in | Medical Sensor

CardioMEMS Sensor Allows Real-Time Monitoring of Heart Failure and Reduces Hospitalizations

In the year after the placement of a CardioMEMS heart failure sensor—developed to wirelessly measure and track pulmonary artery pressures that can signal deteriorating heart failure—patients experienced a 58% decrease in hospitalization for heart failure, according to research presented at the American College of Cardiology’s 68th Annual Scientific Session. Reductions in hospitalizations were noticed in both women and men, spanning all ejection fraction ranges and irrespective of race.

Heart failure, which affects approximately six million Americans, is a condition in which the heart cannot pump sufficient blood at correct pressures to match the needs of the body. CardioMEMS is a small sensor, about the size of a small paperclip that is positioned directly into a patient’s pulmonary artery, which links the heart and the lungs. Using a minimally invasive outpatient procedure, doctors take the femoral vein in the groin to thread the sensor up to the heart. Once implanted, the device can sense increasing pressures in the pulmonary artery, which can be an early warning of fluid backing up in the lungs and imminent onset of congestive heart failure even before weight gain or symptoms of shortness of breath are reported. Pressures are recorded and conveyed electronically from a patient’s home to a safe website so healthcare providers can appraise the readings and proactively regulate medical therapies to maintain patients at their target pressures.

This potential, open-label trial was started as a post-approval study to assess the effectiveness and safety of the CardioMEMS sensor in clinical practice per U.S. Food and Drug Administration (FDA) directives. The device got its FDA approval in May 2014 for use in patients who have New York Heart Association (NYHA) Class III heart failure that restricts daily life and who have been hospitalized for heart failure in the preceding year. The research included 1,200 patients at 104 clinical sites in the U.S. Participants were an average of 69 years old and 38% were women, 30% were with preserved ejection fraction (HFpEF), 17% were non-white, and 53% were with reduced ejection fraction.

This study was done in a large number of patients with substantial representation of women and minorities and showed the device to be not only safe but markedly effective in keeping people out of the hospital. Our findings further validate the concept that remote monitoring of pulmonary artery pressures, which is a surrogate to a patients’ volume status, allows adjustment of medical therapy in a timely manner to prevent future heart failure hospitalizations. This represents an important advance in heart failure management, as these patients are at very high risk of hospitalizations and complications.

David Shavelle, MD, and Study’s Lead Author and Associate Professor, Keck School of Medicine, USC.

The main efficiency endpoint was heart failure hospitalization rates in the year after the sensor was embedded compared to the previous year. Heart failure is among the leading conditions that result in hospitalizations among people aged 65 plus. Patients taking part in the study had an average of 1.24 heart failure hospitalizations in the year before the implant and 0.52 hospitalizations in the year following the device implantation. This converted to a 585 reduction in heart failure-related hospitalizations, the researchers stated. Similar reductions in hospitalizations were observed in patients with the maximum burden of hospitalizations (over two hospitalizations in the earlier year).

Having the device cut the risk of hospitalizations by more than half. The benefits of lower hospitalizations were seen across all subgroups of patients, and we also validated that this treatment can decrease hospitalizations in patients with HFpEF.

David Shavelle, MD, and Study’s Lead Author and Associate Professor, Keck School of Medicine, USC.

The sensor prevented hospitalizations irrespective of patients’ ejection fraction, preserved ejection fraction (50% or higher, which is said to be normal), reduced ejection fraction (<40%) or mid-range ejection fraction (41-50%). Ejection fraction is a measure of how well the heart pumps blood out of the heart to the body. There were also clear advantages for females and racial/ethnic minorities. Females had a 61% decrease in heart failure hospitalization and blacks had a decrease of 53%.

Furthermore, patients with or without a cardiac resynchronization therapy defibrillator or an implantable cardioverter defibrillator and those with an ischemic or non-ischemic cardiomyopathy also experienced lower rates of hospitalizations with the CardioMEMS sensor.

Furthermore, having the device also seemed to decrease all-cause hospitalizations for conditions like chronic obstructive pulmonary disease, pneumonia, or arrhythmias by 28%. Other analyses revealed the combined rate of heart failure-related hospitalizations or death also decreased by 44% after the sensor was implanted.

If you can maintain more normal cardiac filling pressures and less heart stress, you are less likely to be seriously affected and need hospitalization for other conditions such as lung disease or liver disease, which are affected by heart function. We believe that having the sensor monitored by their care team also encourages patients to follow their medication plan and gives them a sense of security that is particularly important for those living far away from a hospital.

David Shavelle, MD, and Study’s Lead Author and Associate Professor, Keck School of Medicine, USC.

The CardioMEMS sensor also matched its safety endpoint—freedom from device or system-related difficulties or sensor failure at one year. To evaluate safety, scientists tracked whether there were any device or system-connected difficulties and episodes of sensor failure where they were incapable of obtaining pressure readings from the device even following troubleshooting of the external electronics. According to the data, only four patients had device- or system-related snags, and there was just one incident of sensor failure, Shavelle said. Reported differently, at one year post-implant, study participants experienced 99.7% freedom from device/system-related difficulties and 99.9% freedom from sensor failure.

A continuing study is assessing the use of the CardioMEMS sensor for patients with other categories of heart failure (NYHA Class II and IV) and for patients at risk but without a previous hospitalization for heart failure.

Abbott Vascular funded this study.

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