ICDs for Primary Prevention: Survival Benefit Lasts 10 Years

Primary prevention implantable cardioverter-defibrillator (ICD) therapy maintained a survival advantage for recipients in the extended term, although not constant for all sorts of heart failure (HF), researchers located. In an extended adhere to-up of the 1,855 sufferers alive at the finish of the SCD-HeFT trial, mortality at 10 years was 52.five% in these randomized to an ICD, 52.7% in these randomized to amiodarone, and 57.two% amongst controls assigned to placebo medication. Thus, the ICD arm kept its survival advantage more than placebo on intention-to-treat evaluation (HR .87, 95% CI .76-.98), according to the group led by Jeanne Poole, MD, of University of Washington Medical Center in Seattle. However, the advantage was attenuated just after six years (P=.0015 for interaction), the group reported in the July 28 situation of the Journal of the American College of Cardiology. "Our results must be interpreted in light of the fact that patients in the non-ICD group were advised at the end of the randomized portion of the trial to have ICD implantation," Poole and colleagues cautioned. Moreover, the influence of ICDs on mortality prices more than 10 years varied according to HF etiology and New York Heart Association (NYHA) functional class: A substantial 19% relative reduction for ischemic HF versus a nonsignificant three% influence in nonischemic HFA substantial 24% advantage in NYHA functional class II but a nonsignificant six% relative raise in NYHA functional class IIIThe query now is which nonischemic cardiomyopathy sufferers can count on extended-term advantage from an ICD, recommended Eric Stecker, MD, MPH, of Oregon Health &amp Science University in Portland, and colleagues in an accompanying editorial. "Although no person randomized trial gives compelling proof of the advantage of ICDs for sufferers with NICM [nonischemic cardiomyopathy], closer examination of the information suggests we really should not dismiss the worth of principal prevention device implantation for these men and women," they argued. Given that nonischemic cardiomyopathy is a "heterogeneous condition with a variety of causes," it is "possible that the absence of long-term mortality benefit among SCD-HeFT participants with NICM was due to an unintended but preferential enrollment of subtypes at relatively lower risk for arrhythmic death in the longer-term," they wrote. "It should also be remembered that survival curves for any therapy, no matter how effective, will eventually converge when plotted over a sufficient time horizon. All individuals 'saved' by their ICD will still eventually die, whether from heart failure progression or another process; it is possible that the intermediate-term benefit of ICD therapy in NICM is overwhelmed by nonarrhythmic death in extended follow-up," according to them. "As current guidelines recommend offering such patients a primary prevention ICD, we are confronted with a common reality ... once the toothpaste is out of the tube, it is hard to get it back in. Given evidence for intermediate-term benefit and the limitations inherent to assessing longer-term benefit, we do not believe it is appropriate to walk back guideline recommendations regarding ICD implantation for NICM patients," Stecker's group maintained. SCD-HeFT initially had two,521 HF sufferers randomized to amiodarone, placebo drug, or implantable cardioverter-defibrillator (ICD) therapy. Eligibility expected NYHA functional class II or III symptoms and left ventricular ejection fraction not exceeding 35%. Investigators reported in 2005 that amiodarone was not located to increase survival more than placebo just after practically four years of adhere to-up, whereas ICD therapy did. "Since then, prophylactic ICD therapy has been established as standard-of-care for patients with similar characteristics to SCD-HeFT patients. Underlying this guideline recommendation is the presumption that the benefits observed over a median of 45.5 months in the initial analysis of the SCD-HeFT trial would be sustained over much of the remaining life expectancy of the study cohort," according to Poole's group. They revisited the SCD-HeFT cohort and have been in a position to extend median adhere to-up up to 11 years. Missing information was a significant limitation of the present evaluation, as extended-term essential status was missing in 9% of persons. "Follow-up data regarding device implantation was only available in 43% of the control group, and among these participants 55% underwent ICD implantation," Stecker's group observed. "Presumably, a substantial proportion of control participants with incomplete device information also had ICDs implanted. This systematic crossover bias would tend to diminish the estimated benefit of ICD therapy in an intention-to-treat analysis," they mentioned. Even so, there is no other ICD trial with adhere to-up extending more than a decade, Poole and colleagues noted. Nicole Lou is a reporter for MedPage Today, exactly where she covers cardiology news and other developments in medicine. Follow Disclosures The study was funded by the National Heart, Lung, and Blood Institute and with a subsidiary grant from St. Jude Medical.Poole disclosed getting institutional investigation help from Medtronic, Biotronik, AtriCure, and Kestra speaking for Boston Scientific, Medtronic, and MediaSphere Medical serving on an Advisory Board for Boston Scientific serving on a study committee for Medtronic becoming on a information and security monitoring board for EBR Systems getting royalties from Elsevier and becoming compensated from the Heart Rhythm Society.Stecker's group had no disclosures.

No Result