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Sildenafil does not improve outcomes in adults with heart failure and preserved EF

Clinical Question:
Is the phosphodiesterase-5 inhibitor sildenafil effective in reducing morbidity and/or mortality in adults with heart failure with preserved ejection fraction?

Bottom Line:
In this study, phosphodiesterase-5 inhibition with sildenafil did not significantly improve outcomes in adults with heart failure with preserved ejection fraction. (LOE = 1b-)

Redfield MM, Chen HH, Borlaug BA, et al, for the RELAX trial. Effect of phosphodiesterase-5 inhibition on exercise capacity and clinical status in heart failure with preserved ejection fraction. A randomized clinical trial. JAMA 2013;309(12):1268-1277.  [PMID:23478662]

Study Design:
Randomized controlled trial (double-blinded)

Industry + govt


Outpatient (any)

Inhibition of phosphodiesterase-5 reduces cardiac structural and functional dysfunction. These investigators identified 216 stable outpatients (median age = 69 years) who met standard clinical and laboratory criteria for heart failure with preserved (greater than or equal to 50%) ejection fraction. Eligible patients randomly received (uncertain allocation concealment) either sildenafil or matched placebo. The study drug was initially administered orally: 20 mg 3 times daily for 12 weeks, with a dose increase to 60 mg 3 times daily for an additional 12 weeks, if tolerated. Individuals masked to treatment group assignment assessed outcomes. Complete follow-up occurred for 92% of participants at 24 weeks. Using intention-to-treat analysis, sildenafil did not significantly improve peak oxygen consumption or 6-minute walking distance compared with placebo. In addition, sildenafil did not significantly reduce hospitalizations, heart failure symptoms, or overall mortality. There were also no significant differences between the 2 groups in adverse events. The study was 85% powered to detect a predetermined relevant difference between the 2 groups.


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