MedWire News: Use of an implantable continuous hemodynamic monitor (ICHM) to guide optimal medical management of patients with heart failure (HF) failed to significantly reduce rates of HF-related events, report researchers.
Nevertheless, Robert Bourge (University of Alabama at Birmingham, USA) and colleagues say their study may have been underpowered to show a difference in event rates between patients with and without ICHM-guided care, and point out that retrospective analysis showed a significant reduction in HF-related hospitalization.
"This suggests the ICHM may have some clinical value," they write in the Journal of the American College of Cardiology.
Patients with advanced HF require close monitoring to detect changes in fluid volume status that warrant modifying their therapy to minimize symptoms and hospitalizations, Bourge and co-workers explain. But current volume assessment methods, such as physical examination or chest radiography, do not always reflect true volume status and early signs of decompensation are often missed.
The researchers evaluated the clinical impact of the Medtronic Chronicle ICHM device on outpatient HF management in the COMPASS-HF trial. The ICHM device continuously measures and stores hemodynamic information that can be reviewed remotely to guide patient management.
COMPASS-HF (Chronicle Offers Management to Patients with Advanced Signs and Symptoms of HF) included 274 New York Heart Association functional class III or IV patients. All patients received optimal medical therapy and 134 patients were randomly assigned to have the ICHM fitted.
Both primary safety endpoints were met, the researchers report, with a complication-free rate of 91.5%, with a 95% confidence interval above 88.7%, and no occurrences of pressor-sensor failure in patients who received an ICHM.
However, the 21% reduction in the primary efficacy endpoint of HF-related events (hospitalizations and emergency or urgent care visits requiring intravenous therapy) at 6 months in the ICHM patients versus no-ICHM patients was nonsignificant.
Nevertheless, a retrospective efficacy analysis showed there was a 36% reduction in the relative risk for a HF-related hospitalization at 6 months with versus without ICHM.
"Additional trials will be necessary to establish the clinical benefit of ICHM-guided care in this patient population," the authors conclude.
In an accompanying editorial, John Teerlink (San Francisco Veterans Affairs Medical Center, California, USA) highlighted that the event rates were lower than would be expected in the community where medication use is below optimal.
He said the design of the trial most likely contributed to the inability to show efficacy of ICHM, with the control group receiving a high rate of visits during follow-up to maintain single-blind status.
Teerlink noted: "The COMPASS-HF trial was a landmark study providing many lessons for future trials, but perhaps the most important lesson is for clinicians caring for patients with HF: frequent interactions between patients and healthcare providers, in conjunction with appropriate use of therapies that improve outcomes, seems to markedly decrease HF-related events."
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