CardioMEMS PA-Pressure Sensor: Prowess, Cautions in HF Management

September 19, 2017

GRAPEVINE, TX —Tracking pulmonary artery pressure (PAP) with an implanted monitor after a heart-failure discharge and using the readings to guide medical therapy improved clinical outcomes in the "real world" about as well as in the device's pivotal randomized trial (CHAMPION), suggest preliminary results of the CardioMEMS HF Post-Approval Study[1].

In the new registry analysis, based on the first 300 patients of a planned enrollment of 1200, use of the monitor (CardioMEMS HF, St Jude Medical/Abbott) to help guide postdischarge meds was associated with significantly reduced PAP compared with the CHAMPION active-treatment (P=0.0476) and control (P<0.0004) cohorts at 6 months.

Dr Nirav Raval

Using the device also seems to cut rates of HF hospitalization compared with the two comparator groups (P<0.01 and P<0.0001, respectively), Dr Nirav Raval (Florida Hospital Transplant Institute, Orlando) reported here at the Heart Failure Society of America 2017 Scientific Meeting.

The findings of the postapproval analysis are consistent with at least two published postapproval CardioMEMS observational experiences from earlier this year, one in 2000 patients and another based on Medicare claims.

The new analysis was underpowered for clinical outcomes, Raval cautioned; events were independently adjudicated, but there were only 56 HF hospitalizations in 43 patients over the 6-month follow-up. Moreover, registry comparisons with cohorts from other studies aren't considered very statistically meaningful.

But it at least seems that the "clinical effect" of using the CardioMEMS monitor in the postapproval study was at least similar to and perhaps even "a bit more robust" than what was seen in the earlier 550-patient CHAMPION trial, Raval said to theheart.org | Medscape Cardiology.

From Trials to Practice

It's noteworthy, he said, that the device's clinical performance didn't seem to erode from the randomized trial to postapproval use in the community, a time when the application of new treatments often broadens to include sometimes higher-risk patients who might not have been included in the original trial, with less impressive results.

"These data are pretty compelling," Dr Robert DiDomenico (University of Illinois at Chicago), who isn't connected to the CardioMEMS studies, said in an interview. There's something to it, he said; the data suggest that using the device to guide medical therapy in the appropriate patients "is an effective way to keep them out of the hospital."

He pointed out, however, that "it requires a big commitment from the institution." The device works only if the patient regularly uploads PAP readings and a system is in place for clinicians to regularly review the data for pressure changes that may or may not be addressed with medication changes.

"It's a big concern about adopting the device," DiDomenico said. "In order to do it effectively, you need the resources to do it in a systematic way. That's the challenge that a lot of smaller sites may have."

And, although the implanted monitoring device is very effective at providing PAP readings, "what you do with that information is just as important," he said. "Just putting in the device and having somebody monitor it is one thing, but making sure there is some standardization for how to manage these people is going to be critical."

Patient Selection

The US Food and Drug Administration approved the CardioMEMS monitor in 2014 for patients in NYHA functional class 3 who had been hospitalized with HF at least once in the past year, essentially the entry criteria of CHAMPION and the postapproval study. Still, the latter's population was a bit different from that of the trial: it was significantly older, included fewer patients with coronary artery disease, and about twice as many had HF with preserved ejection fraction (HFpEF).

But safety outcomes from the postapproval study were not presented, and data are few on the device's potential for complications once it started to be used in clinical practice, Dr Gregg C Fonarow (Ronald Reagan University of California Los Angeles Medical Center) said when interviewed.

In CHAMPION and the experience leading up to the trial, he said, use of the device "was very safe; there were very few procedural complications during implantation and subsequently."

Dr Gregg Fonarow

In contrast, he said, there is new evidence that once the device entered practice and was implanted and followed by "a broader group of clinicians, with maybe variable training in the actual procedure and more real-world patients with comorbidities, there was a higher rate of procedural complications than were seen the CHAMPION trial. Higher rate, and more serious."

Fonarow was referring to an analysis, presented at the HFSA sessions by Dr Muthiah Vaduganathan (Brigham and Women's Hospital, Boston, MA), of CardioMEMS-related adverse-event reports submitted to the FDA's Manufacturer and User Facility Device Experience (MAUDE) database since the device's approval[2].

Potential Serious Risks

From among the >5500 CardioMEMS implants since its approval, there were 155 adverse-event reports submitted to MAUDE, covering 177 distinct adverse events, for a rate of about 2.8%. Vaduganathan called that "low and comparable to that observed in the CHAMPION trial."

He pointed out that MAUDE data doesn't necessarily reflect clinical practice, in that it includes highly selected cases and tilts toward more serious events, which are not adjudicated. Still, it seems to confirm that "patients implanted since FDA approval appear to be higher risk compared with the CHAMPION experience."

The reported adverse events associated with the device, which is implanted in the pulmonary artery via catheter, included device failure or migration in about one-fourth of cases, and access-site complications, HF, arrhythmias, and pulmonary embolism or device thrombosis; each accounted for <10% of the events.

"There were, however, infrequent but potentially consequential procedural and device-related risks of pulmonary-artery injury," Vaduganathan said in his presentation. Cases of pulmonary-artery injury or hemoptysis in 28 patients accounted for about 16% of the adverse events, for an overall rate of about 0.5%. Of those, 14 required ICU admission, seven required intubation, and in six cases the patient died, he reported.

Those findings, Fonarow said, "highlight the need for additional training" for clinicians newly using the device "and strengthening oversight and proctoring procedures. And then perhaps [there should be] additional thought about patient selection."

Fonarow is a coauthor and Vaduganathan is lead author on the MAUDE analysis as published in JAMA Cardiology on September 18, 2017 to coincide with its presentation at the HFSA sessions.

CardioMEMS in Real-World Practice

Robert DiDomenico

"My suspicion is that you're going to see centers that have high readmission rates start to investigate this more broadly than the way that it was studied, because they see this as an opportunity to cut down on their costs in the long term," DiDomenico said.

"It's fertile ground in terms of who it can be used in," he said, and it's starting to be used in higher-risk patients. But that may be "jumping ahead of things. Let's learn to use it in the patients it was studied in first, and then start to advance it."

As the real-world experience grows deeper, the device could well be extended to an even broader population if studies show it could benefit, according to Fonarow. "You could imagine how a NYHA class 2 patient with elevated BNP or N-terminal BNP, whom we know is at higher risk for hospitalization, might also be a candidate."

Abbott funded the CardioMEMS Post Approval Study. Raval reports receiving honoraria from Abbott for consulting. Fonarow discloses "significant consulting for Novartis and modest consulting for Amgen, Janssen Pharmaceuticals, Medtronic, and St Jude Medical (now Abbott). Vaduganathan reports he has no relevant disclosures. Disclosures for the coauthors are listed in the paper.

Follow Steve Stiles on Twitter: @SteveStiles2. For more from theheart.org | Medscape Cardiology, follow us on Twitter and Facebook.

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