UK
Clinical Pharmacy
Association
UK
Clinical Pharmacy
Association
However, monitoring is often suboptimal and hyperkalaemia often inappropriately managed.
Reference ranges may show slight variation but hyperkalaemia as defined by the European Society of Cardiology(ESC) is outlined below:
| Disease Classification | Serum Potassium Level |
|---|---|
| Hypokalaemia | <3.5mmol/L |
| Normal | 3.5-5.0mmol/L |
| Mild hyperkalaemia | 5.0-5.5mmol/L |
| Moderate hyperkalaemia | 5.5-6.0mmol/L |
| Severe hyperkalaemia | >6.0mmol/L |
The prevalence of hyperkalaemia in HF at any given time is expected to be less than five percent, although it is much higher in chronic HF (up to 40 percent) and Chronic Kidney Disease (up to 73 percent) over a one-year follow-up period. Recent HF clinical trials showed an occurrence of hyperkalaemia ranging from 5.2 to 13 percent, with a higher incidence when potassium retaining medications are combined.
Hyperkalaemia in HFrEF can be caused by factors such as impaired potassium elimination, medications, deficiency of aldosterone, high dietary potassium, or excess release of potassium from cells into the blood . HF patients at highest risk of developing hyperkalaemia include patients with renal impairment (up to 50 percent of HFrEF patients) and diabetes mellitus.
Current first-line recommendations for the treatment of patients with HFrEF are illustrated by the Four Pillar approach.
Of these medications, several can cause hyperkalaemia, and using these in combination increases that risk. However, trials with SGLT2-inhibitors in HF have shown a reduced risk of hyperkalaemia compared with placebo in those who received dapagliflozin alongside an MRA, but the mechanism is unclear.
Those with mild-to-moderate hyperkalaemia may be asymptomatic or experience only mild symptoms such as muscle weakness, palpitations, or a slow weak pulse. Severe hyperkalaemia may result in bradycardia and sudden death. Often, hyperkalaemia is only detected on routine blood tests undertaken as part of the recommended monitoring for medications.
Management of hyperkalaemia aims to restore normal levels through intracellular shifting of potassium and/or increasing excretion. Acute hyperkalaemia requires hospital treatment for intravenous therapy, and in severe or life-threatening hyperkalaemia dialysis should be considered.
Treatment options include:
Ongoing management of chronic hyperkalaemia is limited. Options include:
| European Society for Cardiology | NICE |
| Potassium (mEq/L): 4.5-5.0If not taking maximum tolerated guideline recommended dose, initiate and up-titrate RAASi therapy and closely monitor potassium. >5.0 to ≤6.5If taking maximum tolerated guideline recommended dose of RAASi therapy, initiate potassium-lowering therapy, closely monitor potassium and continue potassium-lowering therapy unless another treatable aetiology for hyperkalaemia is identified.If not taking maximum tolerated guideline recommended dose of RAASi therapy, initiate potassium lowering therapy and titrate RAASi therapy once potassium is <5.0, closely monitor potassium and continue potassium-lowering therapy unless another treatable aetiology for hyperkalaemia is identified. >6.5Temporarily stop or reduce RAASi therapy and manage acute hyperkalaemia. If not already initiated, initiate potassium-lowering therapy, closely monitor potassium and continue potassium-lowering therapy unless another treatable aetiology for hyperkalaemia is identified. | Potassium (mEq/L): >5.0Do not initiate RAASi therapy in patients with CKD ≥6.5Discontinue RAASi therapy once other drugs known to increase the risk of hyperkalaemia have been stoppedPotassium binders should only be used in HF/CKD if there is persistent hyperkalaemia (≥6.0mEq/L) and unable to optimise RASSi therapy. |
NB: It is very rarely necessary to stop RAASi therapy in patients with HF and clinical deterioration is likely if treatment is withdrawn. Specialist advice should be sought before treatment discontinuation. This guidance should be used cautiously in patients with chronic kidney disease. Local guidelines may vary.
Patients with HF are at an increased risk of hyperkalaemia for a variety of reasons and are often inappropriately managed, putting the patient at risk of increased morbidity and mortality. Studies show that the benefits of HF medications outweigh the risks, even if they induce hyperkalaemia, provided there is an appropriate surveillance strategy in place. There is no universally accepted consensus regarding best practice, particularly regarding more recently developed potassium binders.
The opinions expressed in this article are those of the author. They do not purport to reflect the opinions or views of the UKCPA or its members. We encourage readers to follow links and references to primary research papers and guidance.
The author declares: no support from any organisation for the submitted work; no financial relationships with any organisations that might have an interest in the submitted work in the previous three years; no other relationships or activities that could appear to have influenced the submitted work.
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