JACC: CRT-D reduces risk of recurring heart failure events

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Cardiac resynchronization therapy with a defibrillator (CRT-D) shows benefit for the prevention of recurring heart failure (HF) events in patients who experienced an initial HF episode, according to a substudy of the MADIT-CRT clinical trial. The substudy also found that the recurrence of HF events greatly increased all-cause mortality risk in this patient population. In an accompanying editorial, the paper is praised for extending clinical knowledge about the long-term effects of CRT. Both the substudy and editorial appear in the Aug. 9 issue of the Journal of the American College of Cardiology.

The cost of care associated with HF in the U.S. totaled $39.2 billion in 2010, with a large part of costs due to readmissions, according to the American Heart Association Statistics Committee. MADIT-CRT (Multicenter Automatic Defibrillator Implantation Trial with Cardiac Resynchronization Therapy) showed a significant reduction in risk of a first HF event or death associated with CRT-D.

In their substudy, Ilan Goldberg, MD, from the cardiology division at the University of Rochester Medical Center in Rochester, N.Y., and colleagues explored whether CRT-D reduced risk in subsequent HF events. 

“Evaluation of recurring HF events has important clinical, quality-of-life and cost-effectiveness considerations that cannot be derived from an evaluation of the risk associated with a first event endpoint,” the authors wrote.

The MADIT-CRT trial enrolled 1,820 patients with mild cardiac symptoms, a reduced ejection fraction and wide QRS complex at 110 hospital centers in the U.S. and Europe. Patients were randomly assigned at a 3:2 ratio to CRT-D arm or an implantable cardioverter-defibrillator arm (ICD). The trial occurred between Dec. 22, 2004, and June 22, 2009, with extended follow-up data through Dec. 31, 2009. The substudy included all 1,820 participants and applied risk analyses and efficacy/intention to treat analyses.

Goldberg and colleagues found active treatment with CRT-D was associated with a 46 percent reduction in the risk of a first HF event compared to ICD-only therapy and a 38 percent risk reduction after the occurrence of a first HF event. They also noted a benefit with CRT-D therapy for the prevention of first and recurring HF events in patients with left bundle branch block.

“Our data suggest that patients who were considered in some prior studies as nonresponders (due to HF event after CRT implantation) might continue to derive a pronounced clinical benefit from CRT even after the occurrence of a post-implantation HF event,” Goldberg and colleagues wrote.     

Additionally, the first and second HF events were determined to be powerful predictors of all-cause mortality, with a seven-fold associated risk of death with the first occurrence of an HF event and a nearly 19-fold associated risk with a second HF event.    

“These findings should be incorporated in the risk assessment and management of patients who receive device therapy for the prevention of HF and sudden cardiac death and stress the importance of evaluating risk for recurrent events in clinical trials,” the authors concluded.

In an editorial, Frieder Braunschweig, MD, PhD, of Karolinska University Hospital in Stockholm, wrote that the paper provided important findings to inform disease management strategies. “Monitoring of HF-relevant parameters with diagnostic features of the CRT-D device might offer a valuable tool for risk assessment and treatment guidance,” he suggested.  He pointed out that the substudy needed to be put in a broader perspective that addressed issues like device-related problems that affect hospital stays and comorbidities in this complex patient population. He recommended more trials be conducted to evaluate patients with HF.