But underuse shown in Swedish study affirming mortality benefit persists
PARIS -- Implantable cardioverter-defibrillators (ICDs) continue to have a primary prevention survival benefit in the modern era of heart failure treatment but are still underused, a Swedish study suggested.
In the SwedeHF registry, just 10% of 16,702 patients eligible for a device under the European Society of Cardiology criteria for ICD prevention of sudden cardiac death in heart failure with reduced ejection fraction (HFrEF) actually got one since 2010.
Benedikt Schrage, MD, of the University Heart Center Hamburg, Germany, reported the results here at the European Society of Cardiology meeting and simultaneously online in Circulation.
"Even if one accounts for patients who may have received an ICD during follow-up and the fact that SwedeHF only includes 54% of patients countrywide, this utilization rate is disappointingly low," Sana Al-Khatib, MD, MHS, of Duke University Medical Center in Durham, North Carolina, and Fred Kusumoto, MD, of the Mayo Clinic in Jacksonville, Florida, wrote in an accompanying editorial.
In a propensity-matched analysis, ICD use was associated with 27% lower all-cause mortality risk at 1 year (12.7% vs 16.9%, P<0.01) and 12% lower such risk at 5 years (47.4% vs 49.5%, P=0.04).
No such difference was seen between groups in risk of hospitalization for renal failure, dialysis, chronic lower respiratory disease, flu and pneumonia, or rheumatoid arthritis as a negative control, which Al-Khatib and Kusumoto said "provides reassurance that worse outcomes in the no-ICD group are not explained by avoidance of ICD implantation in sicker patients."
These findings affirm the 20% to 30% reduction in mortality seen in the MADIT II and SCD-HeFT trials that inaugurated primary prevention ICD use in heart failure 20 years ago, even though it has been questioned due to the falling sudden cardiac death rate in this population as drug therapy has improved, Schrage and colleagues noted in their paper released Sept. 3.
While the DANISH trial played into that anti-ICD argument by showing no survival benefit of primary prevention ICDs in non-ischemic dilated cardiomyopathy, the editorial noted that DANISH had a large crossover to cardiac resynchronization therapy and enrollment criteria for elevated natriuretic peptides that probably selected patients more likely to die from advanced heart failure than sudden cardiac death.
Results in SwedeHF were consistent across subgroups, including by ischemic heart disease etiology, sex, age, period of enrollment, and cardiac resynchronization therapy.
The message now is to get the word out to general practitioners, Schrage said at a press conference for the late-breaking clinical trial.
"I think there is a strong perception of complications of ICD uses and difficulties to implant and maintain the device," he said. "We knew before that the use of ICDs in Sweden is low and we can only speculate about that, that the perception of complications in the general practitioner's mind does not outweigh the benefit of ICDs. I think our message now needs to be that communication of [how] ICD use will reduce morality."
He suggested that the rate of use is higher in the U.S. -- about 60% in one registry.
However, Salim Yusuf, MD, DPhil, of McMaster University's Population Health Research Institute in Hamilton, Ontario, cautioned that this might not be the best comparison.
"Worldwide, the use of ICDs is under 2%. Sweden is one of the wealthier countries of the world. Now you can say it ought to be higher, but don't compare anything with the U.S., because U.S. rates are off the chart for anything expensive you can do," he said from the panel at the press conference. "I don't think you're that far off."
"Whenever you look at rates of use of complex therapies, like ICD, a number of factors have to be taken into account, not just an EF [ejection fraction] in heart failure but what comorbidities do people have, do they have renal failure, are they demented, have they had severe COPD [chronic obstructive pulmonary disease]. These are all factors clinicians take into account in the decision about using it and then patient preferences," Yusuf added. "Just simply comparing numbers doesn't tell you the complete picture."
The study received funding from Boston Scientific and the EU/EFPIA Innovative Medicines Initiative.
Schrage and the editorialists disclosed no relevant relationships with industry.
Source Reference: Schrage B, et al "Association between primary prevention use of implantable cardioverter-defibrillator and mortality in patients with heart failure" Circulation 2019; DOI: 10.1161/CIRCULATIONAHA.119.043012.
Source Reference: Al-Khatib, Kusumoto FM "Implantable Cardioverter Defibrillators Have Stood the Test of Time!" Circulation 2019; DOI:10.1161/CIRCULATIONAHA.119.043354.
Read the original article on Medpage Today: ICDs Still Save Lives in HF