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To Dr. Abraham at Ohio State, one of the developers of the concept of using an implanted PAP monitor to guide management of heart failure patients, CardioMEMS slow take off is not surprising. “It provides physicians with daily information on a patient’s hemodynamics, which is something they never had before except in the catheterization laboratory, intensive care unit or cardiac care unit. Managing patients based on hemodynamics even in the absence of worsening signs and symptoms is a paradigm shift. It takes time to adopt new things.” He noted that most hospitals and health systems already have in place case managers or nurse navigators who run systems that have relied on the insensitive parameters of signs, symptoms, and patients’ weights. The same infrastructure should be able to fairly easily switch to focusing instead on PAP, said Dr. Abraham, professor and director of cardiovascular medicine at Wexner Medical Center.
He acknowledged that the upfront capital cost required to start a CardioMEMS program can poses a financial barrier at many U.S. centers, but once that start-up price is paid the actual implantation into each patient comes close to breaking even with existing reimbursements and the system should eventually result in a return on the investment in the form of reduced readmissions and keeping patients stable, he said. Dr. Abraham suggested that the possibility also exists that maintaining better stability in patients with class III heart failure and preventing episodes of acute decompensation through better-titrated fluid-volume control could produce a long-term change in the natural history of these patients, whose disease historically has been marked by progression to class IV heart failure and the eventual need for a left ventricular assist device, heart transplant, and death. Although this potential impact of refined treatment based on daily PAP monitoring remains to be proven, a secondary analysis from CHAMPION showing a 57% relative reduction in all-cause mortality over an average of 17 months of follow-up that Dr. Abraham reported at the American College of Cardiology annual meeting in March
The hurdle of routine practice
Transitioning CardioMEMS from its successful research track record to everyday clinical practice may pose the trickiest barrier of all. The consensus among heart failure experts seems to be that the best approach to do this successfully is to start slow, focus on the most rational patients within the broad enrollment criteria used in CHAMPION, and then gradually expand from that presuming the first wave of results from routine use at a particular site look similar to those from the trial.
Dr. Akshay S. Desai
“The next big question for PAP monitoring is can we replicate the trial’s success in routine practice? Can this be scaled up?” said Dr. Desai from Brigham and Women’s. “We’re still learning how to identify the right patients, the ones who’ll benefit,”
“The two types of patients we are primarily implanting now are those with classic class III heart failure who were hospitalized during the past 12 months and now are hospitalized again and are right in front of us. They are the lowest-hanging fruit because they are in the hospital today,” said Dr. Abraham. “The second group are the patients who come into the clinic complaining about their symptoms. What we are not yet doing is calling in all patients” with stage III heart failure and a history of at least one hospitalization.”
Other groups are taking a much more selective approach. Dr. Altman and her colleagues in Denver are only targeting patients who have been hospitalized at least twice within the past year, and more specifically patients recently rehospitalized within 30 days of their prior hospitalization. They are also focusing on patients expected to have a high level of compliance with the daily data-collection demands of PAP monitoring and the need to regularly adjust their medication dosages after receiving call backs from their clinicians. This criteria means that they are ruling out patients with a history of substance abuse, she said.
She also noted the need to tailor the target PAP to the specific clinical status of individual patients. Patients with mitral regurgitation, for example, will have a higher “normal” diastolic PAP and hence require a somewhat different target for stability maintenance. “You need to understand each patient’s baseline pressures and adjust their medications based on that,” Dr. Altman said.
“In real life patients tend to be older and sicker, so their benefit may be even greater than what was seen in CHAMPION, but perhaps the results will also be diluted because of comorbidities like renal failure or chronic obstructive pulmonary disease,” said Dr. Butler, although post hoc subanalyses of CHAMPION data showed that these comorbidities did not blunt the positive impact of PAP-guided treatment. “I don’t know if I’ll be successful in selecting the right patients, and whether my interventions in real life will produce the same good outcomes” seen in CHAMPION. “We’ll select patients who are close to the CHAMPION criteria, but not patients on dialysis [who were excluded from CHAMPION]; we’ll select patients with a modest degree of comorbidity and reasonable expected survival,” Dr. Butler said.