A randomized clinical trial conducted by Benjamin O’Brien, MD, PhD, of Charité Universitätsmedizin Berlin, revealed that keeping potassium levels high after cardiac surgery to prevent post-surgical atrial fibrillation (Afib) did not yield the desired results. The study showed that new-onset Afib after isolated coronary artery bypass grafting (CABG) occurred in 26.2% of patients supplemented at a tight potassium threshold of 4.5 mEq/L and 27.8% of patients at a more relaxed supplementation threshold of 3.6 mEq/L. The small risk difference between the two groups did not meet the noninferiority margin, suggesting that the common practice of aggressively supplementing potassium after heart bypass surgery may not be as beneficial as previously thought.
The only significant difference observed between the treatment arms was the cost associated with potassium supplementation. The study found that purchasing and administering potassium cost an average of $111.89 less per patient in the relaxed arm. This cost-saving benefit calls into question the financial justification for routinely maintaining tight control over potassium levels post-cardiac surgery.
Lack of Evidence-Based Practice
Despite the widespread practice of proactively supplementing potassium to achieve high normal levels after cardiac surgery, the study by O’Brien and his team highlighted the lack of solid trial evidence supporting this approach. The researchers emphasized that the findings of their trial suggest that this common practice should be abandoned in favor of reducing patient risk from unnecessary interventions and decreasing healthcare costs. Post-operative Afib, a common complication after CABG, is associated with morbidity, mortality, length of stay, and increased cost of care. However, most interventions aimed at preventing it lack evidence to support their efficacy.
The TIGHT K trial included 1,690 adults scheduled for CABG surgery at 23 cardiac centers in the UK and Germany. Exclusion criteria were put in place to ensure a homogenous study population. Randomization aimed to maintain potassium levels at the upper end of normal for the tight control group, resulting in more frequent potassium administration compared to the relaxed group. Despite the open-label design of the study and higher nonadherence in the tight group, the research findings indicated that potassium supplementation did not have a significant impact on the occurrence of Afib or other secondary outcomes.
The study by O’Brien and his team challenges the conventional wisdom of aggressively supplementing potassium after cardiac surgery. The lack of evidence supporting this practice, coupled with the cost-saving benefits observed in the study, calls for a reevaluation of the current standard of care. Moving forward, clinicians should consider the implications of potassium supplementation on patient outcomes and healthcare costs before adopting a one-size-fits-all approach to post-surgical care.