Iatrogenic hyperkalemia as a serious problem in therapy of cardiovascular diseases in elderly patients

The therapy of cardiovascular diseases has improved rapidly over the past 20 years. The most commonly used medications in cardiac patients are drugs affecting potassium homeostasis in the kidneys or the gastrointestinal tract, particularly inhibitors of renin-angiotensin-aldosterone (RAA) axis. They all can lead to hyperkalemia. This disorder may cause severe damage to the muscles and both the nervous and cardiovascular systems.

The aim of this study was to evaluate the incidence and clinical course of moderate and severe iatrogenic hiperkalemia in patients hospitalized for cardiovascular disease.

The present study analyzed a history of 26 patients with severe or moderate iatrogenic hyperkalemia, selected from among 5553 patients hospitalized in the years 2005-2006 in the Department of Clinical Cardiology of the Swietokrzyskie Cardiology Center, Kielce. They accounted for 0.46% of all patients treated at that time at the Ward.

The concentration of potassium on admission to hospital was > 6.0 mmol/l. Before admission all patients were treated in out-patient clinics with angiotensin-converting enzyme inhibitors, angiotensin II receptor blockers, spironolactone, amiloride, triam-terene, beta-blockers, or potassium supplements administered in monotherapy or in combination. A mean age of patients was 79 years, most of them (80%) were women. The average blood potassium level was 7.3 mmol/l on admision and 5.1 mmol/l at discharge. Severe bradyarrhythmia and complete atrioventricular block requiring temporary pacing (n = 13) were observed in 21 patients (81%). Twenty-four patients (85%) had elevated levels of renal function parameters on admission. The average creatinine level on admission was 2.64 mg/dl, and 2.06 mg/dl on discharge. Ten (38%) out of 26 patients suffered from diabetes and 21 patients (81%) had arterial hypertension. Three out of 26 patients died in the hospital despite intensive therapy.

Polypharmacy should be used with particular caution in subjects treated on the ambulatory basis. During administration of inhibitors of RAA system, particularly in elderly out patients, renal function and serum electrolytes should be appropriately monitored both prior to and during the treatment.