TIGHT K
Trial question
Is relaxed potassium supplementation noninferior to tight potassium supplementation in the prevention of AF after cardiac surgery?
Study design
Multi-center
Open label
RCT
Population
Characteristics of study participants
15.0% female
85.0% male
N = 1667
1667 patients (256 female, 1411 male).
Inclusion criteria: patients with no history of atrial dysrhythmias scheduled for isolated CABG surgery.
Key exclusion criteria: history of AF, atrial flutter, or atrial tachyarrhythmia; preoperative high-degree AV block; use of medication for the purposes of cardiac rhythm management; preoperative serum potassium concentration > 5.5 mEq/L; dialysis-dependent kidney failure.
Interventions
N=830 relaxed potassium control (potassium supplementation in case of serum potassium concentration < 3.6 mEq/L).
N=837 tight potassium control (potassium supplementation in case of serum potassium concentration < 4.5 mEq/L).
Primary outcome
Clinically detected and electrocardiographically confirmed atrial fibrillation after cardiac surgery
27.8%
26.2%
27.8 %
20.9 %
13.9 %
7.0 %
0.0 %
Relaxed potassium
control
Tight potassium
control
Difference not exceeding
non-inferiority
margin ✓
Difference not exceeding non-inferiority margin in clinically detected and electrocardiographically confirmed AF after cardiac surgery (27.8% vs. 26.2%; AD 1.7%, 95% CI -2.6 to 5.9).
Secondary outcomes
No significant difference in ambulatory heart rhythm monitor-detected AF after cardiac surgery (32.2% vs. 33.1%; ARD -0.9, 95% CI -5.8 to 4.1).
No significant difference in clinically or ambulatory heart rhythm monitor-detected AF after cardiac surgery (33.1% vs. 33%; AD 0.1%, 95% CI -4.4 to 4.7).
No significant difference in dysrhythmias other than AF after cardiac surgery (19.1% vs. 21.1%; ARD -2, 95% CI -6.3 to 2.2).
Safety outcomes
No significant difference in adverse events.
Conclusion
In patients with no history of atrial dysrhythmias scheduled for isolated CABG surgery, relaxed potassium control was noninferior to tight potassium control with respect to clinically detected and electrocardiographically confirmed AF after cardiac surgery.
Reference
Benjamin O'Brien, Niall G Campbell, Elizabeth Allen et al. Potassium Supplementation and Prevention of Atrial Fibrillation After Cardiac Surgery: The TIGHT K Randomized Clinical Trial. JAMA. 2024 Sep 24;332(12):979-988.
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