FDA Panel Rejects CardioMEMS Implantable PA-Pressure Monitor for HF

December 09, 2011

December 8, 2011 (Gaithersburg, Maryland) — An FDA advisory panel collectively decided a tiny pulmonary-artery (PA) pressure monitor for patients with heart failure (HF) isn't ready for prime time. The monitor (Champion, CardioMEMS, Atlanta, GA) is vying to be the first solely diagnostic permanent cardiovascular implant.

The panel's vote was mixed: 9 to 1 felt the device is safe; 7 to 3, that it hasn't been shown effective; and 6 to 4, that it hasn't shown its benefits outweigh its risks. Panel members were basing their decision on the randomized, single-blind, company-sponsored CHAMPION trial.

The device keeps track of changes in PA pressures that might alert clinicians to impending decompensation, prompting early adjustments to medications such as vasodilators or diuretics.

The trial suggested that the strategy works: patients implanted with the monitor showed a significant drop in risk of heart-failure–related hospitalizations (p<0.0001) over six months with virtually no important device-related complications, as heartwire previously reported.

Among the panel's concerns: they overwhelmingly agreed that the trial's design made it tough to distinguish any treatment effect from the monitor itself from the overall apparently excellent care patients with the monitor received in the single-blind trial: the clinicians knew which patients had the monitors.

"We can't tell you the device was critically important" to patient outcomes, said acting chair Dr Jeffrey Borer (State University of New York, Downstate Medical Center, NY) in summarizing the panel's opinions. "Something good happened, but we can't tell you what."

The failure of CardioMEMS's case to the panel stemmed largely from reservations the latter had about emails, phone calls, and other communications between the company's nurses and other staff to physicians in the CHAMPION trial. Those communications gave treatment recommendations for specific patients who received the Champion implant.

Although the use of such communications was spelled out in the protocol, they introduced a huge bias in favor of the device, the FDA had proposed--and the panel overwhelmingly agreed.

Speaking for CardioMEMS just before the voting, Dr Lynne W Stevenson (Brigham and Women's Hospital, Boston, MA) had commented on the need for a new, better "signal" to guide therapy in heart failure. And any distinction made between the device itself and the care-delivery support system that went with it in the trial is "totally artificial," she said.

Using the device to guide management, according to Stevenson, "decreases hospitalizations by 25% to 39%. That's a huge impact. That's basically on the order of what happens with beta blockers, what happens with spironolactone, and it's more than what we see with ACE inhibitors.

"I was only a site investigator in this trial," she said. "I just used the device to take care of patients. I can tell you that we [could] make decisions that we've never before been able to make. . . . I know how to take care of each patient now, each one is truly individual, and this is truly patient-centered care. I believe it should be evaluated in terms of the signal and the system that responds to it. I think it distracts us to separate them."

"This was extremely painful"--said Dr Valluvan Jeevanandam (University of Chicago, IL), whose vote said he wasn't convinced there was enough evidence the device is effective--"because as a heart-failure physician I would love to have this and be able to use it to monitor PA pressures. However, I think they demonstrated that it was a combination of the device plus a support mechanism," referring to the email-alert and care systems built into the trial to respond to pressure readings from the monitor.

"I think that in most [experienced] institutions they don't need the support system, and maybe very advanced heart-failure centers can use the numbers and then manage the patients. But I think if you're going to have this as generally applicable to the entire population, the support mechanism does help."

He pointed out that the monitoring device is defined collectively as the implantable sensor, a delivery system, and external electronics for receiving data. "If you added another component, which was the [care] support mechanism, as demonstrated, then my vote would have been yes."

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