AT THE HFSA ANNUAL SCIENTIFIC MEETING
ORLANDO (FRONTLINE MEDICAL NEWS) – Pulmonary artery pressure monitoring using an implanted device was even more effective for controlling pulmonary artery pressures in 2,000 real-world U.S. heart failure patients than it was in the pivotal trial that led to the device’s regulatory approval.
Data from the first 2,000 U.S. heart failure patients to receive the CardioMEMS pulmonary artery (PA) pressure monitoring device and have at least 6 months of follow-up data since the device received Food and Drug Administration approval in 2014 showed that cumulative PA pressure reductions in these patients during the first 6 months of use averaged 434 mm Hg per patient when compared with their baseline PA pressure when they first received the device. This was nearly threefold better than the average 150–mm Hg cumulative reduction in PA pressure per patient during 6 months of use seen in the CHAMPION trial, Dr. William T. Abraham reported at the annual scientific meeting of the Heart Failure Society of America.
Although this analysis of data from the registry maintained for U.S. patients who receive the CardioMEMS device does not yet include information on how these patients fared clinically, and specifically how often they required rehospitalization for heart failure, the strikingly high level of PA pressure control seen in the first 2,000 U.S. patients bodes well for what the clinical findings will show once they are available.
“In our experience with PA pressure monitoring, there is almost a linear relationship between reduced PA pressures and reduced numbers of events” in the form of rehospitalizations for heart failure, said Dr. Abraham, professor of medicine and director of cardiovascular medicine at Ohio State University in Columbus. Once data on outcomes are analyzed for the registry patients, “I think they will be even better than they were in the trial,” he said in an interview.
The PA pressure data in these initial patients “are very important because they tell us that in general use, clinicians – many of whom are at community hospitals – are very capable of using the CardioMEMS data to control patient pressures, and in CHAMPION we showed that there is a relationship between controlled pressures and improved outcomes,” he said. The findings also help allay a key concern about the potential benefit from implanting a device to monitor PA pressure, which is that clinicians must respond to the information and tweak a patient’s diuretic and vasodilator treatments in order for pressure monitoring to have an effect on heart failure outcomes.
“These data clearly refute that concern,” Dr. Abraham said.
He expressed some surprise that PA pressure control with monitoring was so much more effective in real-world use than in the CHAMPION pivotal trial. “In the trial, it was a paradigm shift to manage heart failure patients based on their PA pressures and not according to their symptoms,” he said. With CardioMEMS pressure monitoring, clinicians are supposed to treat high PA pressure with dose adjustments even if the patient feels okay. The new data suggest that clinicians now using the device “have gotten the message that if you don’t do something with the data the patients won’t improve.”
The registry patients came from 47 states and 427 unique physicians who worked in a range of settings including large and small centers, and academic and nonacademic community centers. The patients averaged 70 years, 40% were women, a third had a left ventricular ejection fraction at or above 40%, and their average PA pressure at the time they had their device implanted was 34.9 mm Hg. This pressure was notably higher than the average 31.6 mm Hg pressure among patients enrolled in CHAMPION, a fact that also helps explain why the registry patients received a larger pressure-reduction benefit: They started from a higher level than the trial patients, and during follow-up, their achieved pressures were always compared back to their high baseline pressures.
The registry patients were also substantially older than the trial patients, who had averaged 62 years, and the registry included substantially more women and more patients with higher ejection fractions. Dr. Abraham did not report data on their New York Heart Association class at entry, but labeling for CardioMEMS specifies that patients should have class III heart failure as well as a recent heart failure hospitalization.
Dr. Abraham’s analysis also showed that the greatest degree of PA pressure control occurred in the patients who began device-based treatment with the highest PA pressures. Nearly half the 2,000 registry patients had an entry PA pressure at or above 35 mm Hg, and over a period of 6 months, they averaged a cumulative 876–mm Hg reduction in their PA pressure relative to their baseline level. The third of patients who began with a PA pressure of 25-34 mm Hg had an average 169–mm Hg cumulative pressure reduction over the 6 month period, and the 18% of patients who began with a PA pressure of less than 25 mm Hg actually had an average cumulative increase in the PA pressure of 163 mm Hg. Target PA pressures are usually in the normal range of 18-25 mm Hg.
The analyses also showed that the impact of PA pressure monitoring on pressure was roughly similar regardless of the left ventricular ejection fraction patients had at baseline, and regardless of their sex.
The registry data were collected by St. Jude, the company that markets the CardioMEMS device. Dr. Abraham is a consultant to St. Jude and was lead investigator for the CHAMPION pivotal trial.
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