Spironolactone for heart failure with preserved ejection fraction (HFpEF) - TOPCAT trial

• randomized, double-blind trial:
  • assigned 3445 patients with symptomatic heart failure and a left ventricular ejection fraction of 45% or more to receive either spironolactone (15 to 45 mg daily) or placebo
  • primary outcome was a composite of death from cardiovascular causes, aborted cardiac arrest, or hospitalization for the management of heart failure
• Patient Populations:
  • Symptomatic CHF within 12 months
  • Age>=50 years
  • Left ventricular EF (LVEF)>=45%, assessed within 6 months
  • Controlled systolic BP, defined as a target systolic BP <140 mm Hg; participants with BP up to and including 160 mm Hg were eligible for enrollment if they were on three or more medications to control BP
  • Serum potassium <5.0 mmol/L
  • Stratified based on CHF hospitalization within 12 months (stratum I), or elevated BNP/proBNP within 60 days (stratum II)
    • Number of enrollees: 3,445
    • Duration of follow-up: 6 years (mean 3.3 years)
    • Mean patient age: 69 years
      Percentage female: 52%
    • LVEF: 56%
    • NYHA class: II (64%), III (33%)
  • Exclusions:
    • Recent stroke
    • Recent coronary event
    • Uncontrolled hypertension
    • Estimated glomerular filtration rate <30 or serum creatinine >2.5 mg/dl
    • Hyperkalemia (>=5.0 mmol/L)
    • Restrictive, infiltrative, or hypertrophic cardiomyopathy
    • Life expectancy <3 years

Results

• mean follow-up of 3.3 years, the primary outcome occurred in 320 of 1722 patients in the spironolactone group (18.6%) and 351 of 1723 patients in the placebo group (20.4%) (hazard ratio, 0.89; 95% confidence interval [CI], 0.77 to 1.04; P=0.14)
• of the components of the primary outcome, only hospitalization for heart failure had a significantly lower incidence in the spironolactone group than in the placebo group (206 patients [12.0%] vs. 245 patients [14.2%]; hazard ratio, 0.83; 95% CI, 0.69 to 0.99, P=0.04)
  • neither total deaths nor hospitalizations for any reason were significantly reduced by spironolactone
• treatment with spironolactone was associated with increased serum creatinine levels and a doubling of the rate of hyperkalemia (18.7%, vs. 9.1% in the placebo group) but reduced hypokalemia. With frequent monitoring, there were no significant differences in the incidence of serious adverse events, a serum creatinine level of 3.0 mg per deciliter (265 μmol per liter) or higher, or dialysis.

Conclusions

• study authors concluded that "..In patients with heart failure and a preserved ejection fraction, treatment with spironolactone did not significantly reduce the incidence of the primary composite outcome of death from cardiovascular causes, aborted cardiac arrest, or hospitalization for the management of heart failure.."
  
  
• "results of the TOPCAT trial indicate that spironolactone is not superior to placebo in improving CV outcomes in patients with HFpEF. The majority of these patients were already on an ACEI/ARB. There was also a significantly higher rate of hyperkalemia and renal failure in patients treated with spironolactone. The reduction in CHF hospitalizations with spironolactone is hypothesis generating and deserves further study. Similarly, a reduction in mortality for women is hypothesis generating and deserves further study...findings do not support a role for mineralocorticoid receptor antagonists in these patients. It is also important to note that although historically considered a diagnosis of exclusion, recent guidelines suggest employing objective clinical and imaging criteria for HFpEF, which include protocols for excluding HFpEF. The exact characterization of patients with HFpEF in the current trial is not available. Heterogeneity among patients may have impacted the results as well" (2)

Reference:

• Pitt B et al. Spironolactone for Heart Failure with Preserved Ejection Fraction. N Engl J Med 2014; 370:1383-1392
• Bhatt DL. Treatment of Preserved Cardiac Function Heart Failure With an Aldosterone Antagonist - TOPCAT. American College of Cardiology (Accessed 30/7/2020)