How to deal with heart failure patients with hyperkalemia❓❓❓

Heart failure is a group of complex clinical syndromes caused by abnormal changes in the structure and/or function of the heart caused by a variety of reasons, causing ventricular contraction and/or diastolic dysfunction. It is the end stage of cardiovascular disease. Hyperkalemia is a common complication of heart failure, which can lead to severe arrhythmia and even life-threatening. 

Hyperkalemia is diagnosed when serum potassium> 5.0 mmol/L.

The risk of death is significantly increased when serum potassium is > 5.0 mmol/L. Therefore, hyperkalemia can be diagnosed with a serum potassium level  > 5.0 mmol/L. Serum potassium level  is 5.0-5.5 mmol/L, it is mild hyperkalemia. Serum potassium level  is 5.6-6.0 mmol/L, it is moderate hyperkalemia. Serum potassium level  is > 6.0 mmol/L, it is severe hyperkalemia. Serum potassium rises to more than 5.0mmol/L in a short time, which is an acute hyperkalemia. Repeated episodes of hyperkalemia within 1 year belong to chronic hyperkalemia.

Clinical manifestations of hyperkalemia.

The clinical symptoms caused by hyperkalemia are mainly related to the decreased excitability of myocardium and neuromuscular. The severity is related to the degree and speed of blood potassium increase, and whether it is combined with other electrolyte and water metabolism disorders. Mild hyperkalemia usually has no clinical symptoms. Acute severe hyperkalemia may cause brady paralysis, fatal arrhythmia, and even cardiac arrest and other serious consequences.

Diagnosis of hyperkalemia.

The diagnosis of hyperkalemia must exclude pseudo-hyperkalemia caused by hemolysis caused by improper blood sampling and inspection. When there is clinical doubt, it is recommended to repeat the examination to confirm the diagnosis and avoid making the wrong clinical treatment. The rare causes of hyperkalemia include rhabdomyolysis syndrome, tumor cell lysis syndrome, adrenal cortex hypofunction, etc. Related examinations are also required if necessary.

Treatment of heart failure combined with hyperkalemia.

1. General treatment and dietary advice.

Comorbidities, medication and diet should be fully evaluated after the diagnosis of hyperkalemia in patients with heart failure. For example, diabetes, chronic kidney disease and hypertension are comorbidities related to hyperkalemia. It should be actively treated once discovered. Although the commonly used drugs such as angiotensin converting enzyme inhibitors (ACEI), angiotensin II receptor antagonists (ARB), β-receptor blockers and aldosterone receptor antagonists in patients with heart failure can cause hyperkalemia, they can still be used reasonably since it is of great significance to improve the prognosis of patients with heart failure. 

• Serum potassium > 5.5 mmol/L can reduce the dose and use potassium-lowering drugs as appropriate. Unless serum potassium is > 6.5 mmol/L or there is a critical situation related to hyperkalemia. The medicines should not be stopped suddenly. It is recommended to maintain serum potassium with using potassium-lowering drugs adequately and reasonably under stable conditions.

In terms of diet, for patients with serum potassium > 5.0 mmol/L and chronic hyperkalemia. It should limit appropriately the intake of high-potassium foods, such as potassium-containing salt, banana, oranges, tomatoes, potatoes and other high-potassium foods Intake. However, since foods generally contain potassium, strict implementation of a low-potassium diet may lead to insufficient intake of dietary fiber and various nutrients. Therefore, it is not recommended to implement an excessively strict low-potassium diet. Instead, long-term oral potassium-lowering drugs should be used to maintain blood potassium stability.

2. Treatment of acute episodes of hyperkalemia.

Stabilize the membrane potential of myocardial cells: intravenous calcium can be used as the first-line emergency treatment of hyperkalemia. The calcium administration process needs to be completed under ECG monitoring.

Promote the transport of extracellular potassium ions into the cell: insulin + glucose or sodium bicarbonate are commonly used treatment options.

Promote the excretion of potassium ions from the body: mainly include potassium excretion diuretics, cation exchange resins, new potassium ion binders and blood purification treatments.

• Potassium excretion diuretics: mainly include loop diuretics (such as furosemide) and thiazide diuretics (such as hydrochlorothiazide). Loop diuretics have a stronger potassium excretion effect than thiazide diuretics. For loop diuretics, the effect of intravenous administration is better than oral administration, and the combined effect of the two types of diuretics is better. The prerequisite for the use of diuretics is that the patient has good renal function and no hypovolemia, otherwise the curative effect will be poor and the condition may be aggravated.
• New potassium ion binders such as sodium zirconium cyclosilicate and Patiromer. The usage of SZC in acute hyperkalemia: The recommended starting dose is 10 g, 3 times a day, orally, and the medication should not exceed 48 hours. SZC has few adverse reactions, mainly diarrhea. Patiromer has a slower onset of effect after oral administration.
• Blood purification treatment: Hemodialysis is the most efficient way to remove potassium ions from the body. Hemodialysis is suitable for patients with continuous serum potassium> 6 mmol/L or abnormal electrocardiogram, and the effect of drug treatment is poor, especially for patients with heart failure who also have a water overload.

3. Treatment of chronic hyperkalemia.

Patients with chronic hyperkalemia need long-term use of potassium-lowering drugs to maintain blood potassium stability. The treatment measures need to consider safety, effectiveness and operability. In addition to the above general treatment and dietary recommendations, the following drug interventions can be taken:

For patients with metabolic acidosis, sodium bicarbonate can be used.

For patients with certain renal reserve, potassium excretion diuretics can be used, but the adverse reactions caused by long-term medication should be noted.

For patients with heart failure with extremely poor renal function and recurrent hyperkalemia, long-term dialysis can be used for treatment.

New potassium ion binders such as sodium zirconium cyclosilicate can maintain blood potassium stability for up to 1 year of treatment.

Prognosis and management of heart failure combined with hyperkalemia.

All patients with chronic heart failure should actively monitor blood potassium on a regular basis.