Promising results need confirmation
Medical therapy for heart failure guided by an implanted pulmonary artery pressure (PAP) sensor didn’t improve survival or risk for HF events like hospitalization over a year in a major randomized trial that entered a broad range of patients with mild to moderate disease.
But medical therapy adjustments based on PAP readings from the miniature CardioMEMS (Abbott) implant might well have surpassed conventional HF management for outcomes had the world not been turned upside down by SARS-CoV-2 and the pandemic lockdowns, assert researchers from the GUIDE-HF trial.
Something about the crisis, they concluded – although not without some pushback – led to better outcomes in the standard-care control group, apparently muddling any potential differences from those on PAP-guided management.
Working with regulators, the team conducted a “pre–COVID-19 impact analysis” that compared outcomes before the March 2020 national COVID-19 emergency declaration that forced much of the United States with shelter in place.
By that time, all of the trial’s patients had been followed for at least 3 months, and about three-fourths of its endpoints had already been counted, JoAnn Lindenfeld, MD, Vanderbilt University Medical Center, Nashville, Tenn., said at a media briefing prior to unveiling GUIDE-HF at the all-virtual European Society of Cardiology Congress 2021.
The pre–COVID-19 analysis, approved several months before the end of the trial – while the data were still blinded – had been “suggested by both regulatory agencies and professional societies in Europe and in the United States,” Dr. Lindenfeld said.
It pointed to a possible benefit for the CardioMEMS-guided strategy, a barely significant 19% drop in risk (P = .049) for the primary endpoint of death, HF hospitalization, or urgent HF hospital visit. The effect was driven by a 24% decline in HF events (P = .014), with no significant contribution from mortality.
“The benefits of hemodynamic monitoring and management in reducing heart failure hospitalizations extended to patients with less severe heart failure”; that is, those in New York Heart Association class 2 and any in NYHA class 3 with “elevated natriuretic peptides but no previous hospitalization,” said Dr. Lindenfeld, who is also lead author on the GUIDE-HF report published in the Lancet.
Such benefits would suggest that CardioMEMS-guided management can improve outcomes in an HF population much broader than the device’s current indication.
But as it happens, the trial’s prospectively defined 12-month primary outcomes were less impressive. A 12% decline in risk for the composite endpoint among patients managed by CardioMEMS failed to reach significance compared with standard management (P = .16).
“Several factors could explain the considerable loss of benefit of hemodynamic-guided management during the COVID-19 pandemic,” the Lancet report explained. They include “improved patient compliance with medical and dietary regimens, reduced respiratory infections, altered health-care provider behavior, changes in disease progression due to COVID-19, or other as yet unknown effects of a major pandemic.”
Expanded population
Importantly, GUIDE-HF had entered 1,000 patients in NYHA class 2-4 and either an HF hospitalization in the previous year or elevated natriuretic peptide levels. About 44% of the entrants in NYHA class 3 did not have a 1-year history of HF hospitalization.
That’s a more heterogeneous and potentially lower-risk cohort than patients in the randomized CHAMPION study of 11 years ago, which led to the implant’s approval on both sides of the Atlantic.
In that trial, CardioMEMS-guided management was followed by 30% drop in risk for HF hospitalization over 6 months (P < .001). But CHAMPION was limited to patients in NYHA class 3 with a history of HF hospitalization, the device’s current indication in both the United States and Europe.
The GUIDE-HF findings “reinforce that patients with class 3 heart failure and prior heart failure hospitalization are those in whom there is the clearest benefit, based on the prior CHAMPION trial. These are the patients where this monitoring strategy may be best targeted,” Gregg C. Fonarow, MD, University of California Los Angeles Medical Center, said in an interview.
Although GUIDE-HF didn’t show a significant benefit for NYHA class 2 patients with elevated biomarkers, who aren’t covered by the device’s current labeling, that group showed “some suggestions of potential benefit,” noted Dr. Fonarow, who isn’t a coauthor on the Lancet report. So, “there may be select patients with class 2 heart failure where monitoring could be considered on a case-by-case basis.”
In an interview, Larry A. Allen, MD, MHS, said that, “while the technology is pretty amazing, the real question is whether it tells us something that we didn’t already know that leads to improved care. Unfortunately, as tested here, it doesn’t, or at least not enough to make a big difference.”
The pre–COVID-19 impact analysis “should be interpreted with caution, and not as the primary finding,” Dr. Allen, from the University of Colorado at Denver, Aurora, who is not a GUIDE-HF coauthor, said in an interview.
One might hypothesize, he said, “that, in the setting of limited in-person visits with loss of physical examination, perhaps CardioMEMS would be more – not less – helpful during the pandemic. And yet the opposite was seen.”
The pandemic has “markedly altered all kinds of aspects of patient care and trial conduct, but that doesn’t make the data derived during that period uninformative,” Dr. Allen said. “And as we are increasingly reminded, the future will be a new normal, not a prepandemic normal.”
A third group
The GUIDE-HF trial includes, in addition to the 1,000 randomized patients, a single-group observational cohort of 2,600 patients, whose outcomes will be reported at another time, noted the published report.
But in the randomized comparison, conducted at 118 centers in North America, all patients were implanted with the CardioMEMS device and blinded as to their assigned strategy. Enrollment took place between March 2018 and Dec. 20, 2019.
Of the 1,000 successfully implanted patients, 497 were assigned to the pressure-guided strategy, in which “titration of diuretics was recommended if pulmonary artery pressure provided evidence of excess intravascular volume, and titration of vasodilators was recommended if elevated vascular resistance was evident,” the report stated.
The remaining 503 patients assigned to standard care served as control subjects, for whom “investigators were aware of treatment assignment but did not have access to PAP data.”
The hazard ratio for the primary endpoint in the pressure-guided group, compared with the control group, was 0.88 (95% confidence interval, 0.74-1.05; P = .16) over a median follow-up of 11.7 months.
But in the sensitivity analysis comparing outcomes before and after the COVID-19 lockdowns, using established methodology, the report stated, the primary-endpoint HR was 0.81 (95% CI, 0.66-1.00; P = .049).
The difference is owed to improved outcomes in the control group under pandemic conditions, the researchers concluded. Patients assigned to conventional management –whatever that meant during shelter-in-place – experienced 21% fewer primary-endpoint events than their own rate before the pandemic. After the COVID-19 emergency was declared, there was no significant difference in event rates between the two randomization groups.
In the primary 12-month analysis, the HR for HF events in the guided-therapy was not significant reduced, at 0.85 (95% CI, 0.70-1.03; P = .096). But in the pre-COVID-19 analysis, that risk fell significantly with CardioMEMS-guided management, for an HR of 0.76 (95% CI, 0.61-0.95; P = .014).
An editorial accompanying the GUIDE-HF publication (Lancet. 2021 Aug 27. doi: 10.1016/S0140-6736[21]01914-0) asserts that the trial “did not enroll an ideal group of patients for showing the efficacy of pulmonary artery pressure monitoring, since many had baseline pressures in the target range with little possibility of short-term gain.”
Also, wrote John G. F. Cleland, MD, PhD, University of Glasgow, and Pierpaolo Pellicori, MD, Imperial College London, “follow-up was too short, and interventions did not substantially change pulmonary artery pressure.”
They continue: “Monitoring alone cannot improve outcome, but consequent actions might. The GUIDE-HF results are encouraging but inconclusive, and should inform further research, possibly a large, simple, open-label trial to investigate a system of care rather than a single technology.”
GUIDE-HF was funded by Abbott. Dr. Lindenfeld disclosed receiving research grants from AstraZeneca, Sensible Medical, and Volumetrix; and consulting for Abbott, Alleviant Medical, AstraZeneca, Boehringer Ingelheim, Boston Scientific, CVRx, Edwards, Impulse Dynamics, and VWave. Dr. Fonarow reported consulting for Abbott and that his institution has participated in the GUIDE-HF trial; he has elsewhere disclosed consulting for Amgen, AstraZeneca, CHF Solutions Lifesciences, Janssen, Medtronic, and Novartis. Dr. Allen had elsewhere reported consulting for Abbott, Amgen, Boston Scientific, and Novartis. Dr. Cleland disclosed receiving personal fees from Abbott for serving on an advisory board for the MitraClip device, unrelated to the CardioMEMS device. Dr. Pellicori reported no relevant conflicts.
A version of this article first appeared on Medscape.com.