Supplementing potassium for patients who have undergone coronary artery bypass graft (CABG) surgery—a routine practice following the procedure—may not be necessary according to new evidence presented at the European Society of Cardiology (ESC) 2024 Congress (30 August–2 September, London, UK).
Investigator Benjamin O’Brien from the Deutsches Herzzentrum der Charité (Berlin, Germany) reported that giving potassium supplements only when levels dropped below the lower limit of normal was non-inferior to routinely supplementing potassium to the upper limit of normal.
The trial enrolled patients with no history of atrial dysrhythmias and scheduled for isolated CABG surgery were recruited across 23 centres in the UK and Germany.
Patients were randomised in a 1:1 ratio to a strategy of tight potassium control (potassium supplementation if serum levels fell below 4.5 mEq/L) or relaxed potassium control (potassium supplementation only if serum levels fell below 3.6 mEq/L).
The primary endpoint was the presence of new-onset AF after cardiac surgery (AFACS) in the 120 hours (5 days) after the operation, or up until discharge from hospital, whichever was sooner.
In total, 1,690 participants were randomised, with a mean age of 64.7 years and 15% were female. The mean European System for Cardiac Operative Risk Evaluation (EuroSCORE) II score was 1.5%.
There was no significant difference in the primary endpoint, which occurred in 27.8% of patients in the relaxed control group and 26.2% in the tight control group.
The rate of AFACS detected by any means (clinically and/or by ambulatory heart rhythm monitoring) was 33% in both groups.
“We were able to show that routinely supplementing potassium for tight control offers no benefits compared with relaxed control but is more expensive. Unnecessary intervention can carry risks, such as drug errors, and can negatively impact the patient experience, for example, the unpleasant taste of oral potassium supplements,” said O’Brien. “So, the results from TIGHT-K are good news – we can safely stop the widespread practice of maintaining high-normal potassium levels after isolated CABG, improve the patient experience and also save money.”
