Deutsches Herzzentrum der Charité, Charité - Universitätsmedizin Berlin, Germany.
St Bartholomew's Hospital, Barts Health NHS Trust, London, United Kingdom.
JAMA. 2024 Sep 24;332(12):979-988. doi: 10.1001/jama.2024.17888.
Supplementing potassium in an effort to maintain high-normal serum concentrations is a widespread strategy used to prevent atrial fibrillation after cardiac surgery (AFACS), but is not evidence-based, carries risks, and is costly.
To determine whether a lower serum potassium concentration trigger for supplementation is noninferior to a high-normal trigger.
DESIGN, SETTING, AND PARTICIPANTS: This open-label, noninferiority, randomized clinical trial was conducted at 23 cardiac surgical centers in the United Kingdom and Germany. Between October 20, 2020, and November 16, 2023, patients with no history of atrial dysrhythmias scheduled for isolated coronary artery bypass grafting (CABG) surgery were enrolled. The last study patient was discharged from the hospital on December 11, 2023.
Patients were randomly assigned to a strategy of tight or relaxed potassium control (only supplementing if serum potassium concentration fell below 4.5 mEq/L or 3.6 mEq/L, respectively). Patients wore an ambulatory heart rhythm monitor, which was analyzed by a core laboratory masked to treatment assignment.
The prespecified primary end point was clinically detected and electrocardiographically confirmed new-onset AFACS in the first 120 hours after CABG surgery or until hospital discharge, whichever occurred first. All primary outcome events were validated by an event validation committee, which was masked to treatment assignment. Noninferiority of relaxed potassium control was defined as a risk difference for new-onset AFACS with associated upper bound of a 1-sided 97.5% CI of less than 10%. Secondary outcomes included other heart rhythm-related events, clinical outcomes, and cost related to the intervention.
A total of 1690 patients (mean age, 65 years; 256 [15%] females) were randomized. The primary end point occurred in 26.2% of patients (n = 219) in the tight group and 27.8% of patients (n = 231) in the relaxed group, which is a risk difference of 1.7% (95% CI, -2.6% to 5.9%). There was no difference between the groups in the incidence of at least 1 AFACS episode detected by any means or by ambulatory heart rhythm monitor alone, non-AFACS dysrhythmias, in-patient mortality, or length of stay. Per-patient cost for purchasing and administering potassium was significantly lower in the relaxed group (mean difference, $111.89 [95% CI, $103.60-$120.19]; P <.001).
For AFACS prophylaxis, supplementation only when serum potassium concentration fell below 3.6 mEq/L was noninferior to the current widespread practice of supplementing potassium to maintain a serum potassium concentration greater than or equal to 4.5 mEq/L. The lower threshold of supplementation was not associated with any increase in dysrhythmias or adverse clinical outcomes.
ClinicalTrials.gov Identifier: NCT04053816.
为维持血清中钾离子浓度处于高正常值，补充钾离子是一种广泛应用于心脏手术后（AFACS）预防心房颤动的策略，但这种策略没有充分的证据支持，存在风险，且费用高昂。
确定补充钾离子的血清钾离子浓度触发值较低是否不劣于高正常值触发值。
设计、地点和参与者：这是一项在英国和德国的 23 个心脏外科中心进行的开放标签、非劣效性、随机临床试验。研究对象为 2020 年 10 月 20 日至 2023 年 11 月 16 日期间无房性心律失常病史、计划行单纯冠状动脉旁路移植术（CABG）的患者。最后一名研究患者于 2023 年 12 月 11 日出院。
患者被随机分配至严格或宽松的钾离子控制策略组（仅当血清钾离子浓度降至 4.5 mEq/L 或 3.6 mEq/L 以下时才补充钾离子）。患者佩戴便携式动态心电图监测仪，由核心实验室进行分析，核心实验室对治疗分组情况不知情。
预先设定的主要终点是在 CABG 手术后 120 小时内或首次出现新发 AFACS 或直至出院前（以先发生者为准），临床发现和心电图确认的新发 AFACS。所有主要结局事件均由对治疗分组不知情的事件验证委员会进行验证。宽松的钾离子控制策略不劣于定义为新发 AFACS 风险差异的 97.5%CI 上限为单侧 1 边小于 10%。次要结局包括其他与心律相关的事件、临床结局和与干预相关的成本。
共纳入 1690 名患者（平均年龄 65 岁；256 [15%] 名女性）。在严格组中，26.2%（219 例）的患者发生主要终点事件，在宽松组中，27.8%（231 例）的患者发生主要终点事件，风险差异为 1.7%（95%CI，-2.6%至 5.9%）。两组间任何方法检测到的 AFACS 发作发生率或单独使用动态心电图监测仪检测到的 AFACS 发作发生率、非 AFACS 心律失常发生率、住院死亡率或住院时间均无差异。宽松组每位患者购买和使用钾离子的成本显著降低（平均差值，$111.89 [95%CI，$103.60-$120.19]；P <.001）。
对于 AFACS 的预防，仅当血清钾离子浓度降至 3.6 mEq/L 以下时才进行补充，与目前广泛采用的维持血清钾离子浓度大于或等于 4.5 mEq/L 的做法相比，不劣于后者。较低的补充阈值与心律失常或不良临床结局的增加无关。
ClinicalTrials.gov 标识符：NCT04053816。
