RESUMO
INTRODUCTION AND OBJECTIVES: Neurohormonal blockade (NB)/modulation is the combination of two renin-angiotensin-aldosterone system inhibitors (RAASi) with a beta blocker. It is the core therapy for heart failure with reduced ejection fraction (HFrEF). While improving long term prognosis, it also induces hyperkalemia (serum K+ >5.0 mEq/L) due to RAASi effects. This may cause lethal arrhythmias and increase mortality in the short term. Thus, hyperkalemia frequently leads to withholding or reducing the intensity of neurohormonal blockade/modulation, which is associated with worsening long term prognosis. We assessed the relevance of hyperkalemia as a limiting factor of neurohormonal blockade/modulation in real life clinical conditions. METHODS: We reviewed the medical records of HFrEF patients attending a HF clinic at a tertiary Portuguese hospital during 2018 (n=240). The number of patients not tolerating maximal neurohormonal blockade/modulation due to hyperkalemia was determined. The incidence and characteristics of hyperkalemia episodes were also assessed. RESULTS: Only six patients (3%) achieved maximal doses of neurohormonal blockade/modulation. Hyperkalemia was the limiting factor in 48 (20%) patients. A total of 185 hyperkalemia episodes occurred in 100 (42%) patients. Forty-five (24%) episodes were moderate or severe (serum K+ >5.5 mEq/L). In these HFrEF patients, the co-existence of hypertension, diabetes or renal failure was associated with the occurrence of hyperkalemia. CONCLUSIONS: In daily clinical practice, hyperkalemia is frequent and limits neurohormonal blockade/modulation by leading to the withholding or reducing of the intensity of RAAS inhibition. Considering the negative prognostic impact associated with sub-optimal neurohormonal blockade/modulation, addressing hyperkalemia is an important issue when treating HFrEF patients.
RESUMO
The current paradigm of medical therapy for heart failure with reduced ejection fraction (HFrEF) is triple neurohormonal blockade with an angiotensin-converting enzyme inhibitor (ACEI), a beta-blocker (BB) and a mineralocorticoid receptor antagonist (MRA). However, three-year mortality remains over 30%. Stimulation of counter-regulatory systems in addition to neurohormonal blockade constitutes a new paradigm, termed neurohormonal modulation. Sacubitril/valsartan is the first element of this new strategy. PARADIGM-HF was the largest randomized clinical trial conducted in HFrEF. It included 8442 patients and compared the efficacy and safety of sacubitril/valsartan versus enalapril. The primary endpoint was the composite of cardiovascular mortality and hospitalization due to HF, which occurred in 914 (21.8%) patients receiving sacubitril/valsartan and in 1117 (26.5%) patients receiving enalapril (HR 0.8, 95% CI 0.73-0.87, p=0.0000002; NNT 21). Sacubitril/valsartan reduced both primary endpoint components, as well as sudden cardiac death, death due to worsening HF, and death from all causes. Patients on sacubitril/valsartan reported less frequent deterioration of HF and of quality of life, and discontinued study medication less frequently because of an adverse event. PARADIGM-HF demonstrated the superiority of sacubitril/valsartan over enalapril, with a 20% greater impact on cardiovascular mortality compared to ACEIs. Accordingly, in 2016, the European (ESC) and American (ACC/AHA/HFSA) cardiology societies simultaneously issued a class I recommendation for the replacement of ACEIs by sacubitril/valsartan in patients resembling PARADIGM-HF trial participants.