Potassium Supplementation and Prevention of Atrial Fibrillation After Cardiac Surgery
Authors: O’Brien Benjamin , Campbell Niall G. , Allen Elizabeth , Jamal Zahra , Sturgess Joanna , Sanders Julie , Opondo Charles , Roberts Neil , Aron Jonathan , Maccaroni Maria Rita , Gould Richard , Kirmani Bilal H. , Gibbison Ben , Kunst Gudrun , Zarbock Alexander , Kleine-Brüggeney Maren , Stoppe Christian , Pearce Keith , Hughes Mark , Van Dyck Laura , Evans Richard , Montgomery Hugh E. , Elbourne Diana ,   TIGHT K investigators, Henderson Robert , Desai Jatin , Keane David , Ruetzler Kurt , Stevenson Steve , Duncker Richard , Magboo Rosalie , Barrett Nicholas A. , Jones Philip M. , Yu Ly-Mee , Kiaii Bob , Lobban Trudie , Sanders Julie , Roberts Neil , Welch Sophie , Williams Christabel , Hughes Gemma , Baker Victoria , Garcia Floresca , Sfakianakis Chrysanthos , Baldey Melissa , Chan Carmen , de Sousa Jorge Couto , Abbass Hakam , Campbell Niall , Kimani Linda , Szentgyorgyi Lajos , Rankin Louise , Athanasakis Efstratios , Muthuswamy Akhila , Allanson Alison , Lewis Anna , Finch Arron , Fowe Folakemi , Paulus Lahja , Singh Bisma Chellam , Mathew Preetha , Sunil Reshma Dutt , Mathews Jesha , Crasta Sheetal , Ferguson Susan , Allen Schvearn , Pokharel Seema , Nicholas Anie , Pailing Adam , Kunst Gudrun , Noble Harriet , Saha Sian , O’Reilly Kevin , Spooner Caitlin , Clarey Emma , Finney Clare , Broderick Anna , Depante Maria Theresa , Meeks Daveena , Pappa Paraskevi , Dymore-Brown Laura-Anne , Samuels Rebecca , Sandhar Tajwinder , Karami Fatemeh , Axalan Annette , Vergara Burt , Corcoran  Eleanor         , Loubani Mahmoud , Ford Sarah , Rowe Kay , Dobbs Karen , Bulemfu Jeanne , Harper Paul , Sanders Jack , Lip Gregory , Kirmani Bilal H , Baker Maureen , Keogan Lynne , Panda Abinash , Kotalczyk Agnieszka , Fawzy Ameenathul Mazaya , Harikumar Bindu , Clements Cheryl , McQuade Lorraine , Widdows Peris , Winstanley Phoebe , Mathew Sherly , Collins Tom , Punjabi Prakash P. , Ross Alexandra , Dixit Dimple , Lodge Christopher , Calvelo Ellen , Sefi Leonora , Tuason Maricris , Russell Mark , Mariveles Myril , Lopez Rebeca Toledano , Kyriazis Panagiotis G , Liu Giuqing , Chacko Jacob , Gould Richard , Wilby Elizabeth , Speight Abigail , Ogg Bethan , Watts Sarah , Mathew Shailamma , Salada Sheila , Trott Susan , Friar Zoe , Brennan Charon , Rawnsley Emma , Long Kate , Bose Amal , Martinovsky Petr , Sebastian Deepa , Vasudevan Vasanthi , Aron Jonathan , Handslip Rhodri , Farnell-Ward Sarah , Aquino Christine , Thanasi Maria , Valcher Massimiliano , Yun Nikki , Al-Subaie Nawaf , Kabungo Pamela , Dangol Shreeja , Ventura Vincent , Whittaker Liam , Luna Amylene , Fernandes Edna , Lloyd Karen , Cordoba Maria Maiz , Kanu Rebecca , Juncu Roxana , Sadeque Syed , Rosser Jon , Shoeib Mohamed , Cheng Ann , Ford Amber , Holmes Olivia , Blackwell Chris , Thompson Mollie , Waspe Jennifer , Massey John , Hyde Jonathan , Martinez Dawn , Strikaite Justina , Bennett Lorraine , Skipper Nicola , Appasamy Sara , Trivedi Uday , Balmforth Damian , Lewis Michael , Krasopoulos George , Nixon Lydia , Sawyer Jo , Joines Charlotte , New Katharine , Hartley Amy , Webster David , Johnson Andrew , Kourliouros Antonios , Sastry Priya , Walcot Nicholas , Proctor Ann , Srivastaka Vivek , Castro Christine , Budden Amanda , Park James , McMillan Claire , Williams Georgia , Eladawy Mostafa , Bradbury Rebecca , Somarajan Sam , Jones Samantha , Maccaroni Maria , Musson Kelly , Ramirez Jonaifah , Redman Emily , Benson Faye , Goodsell Kerry , Eve Michelle , Matias Sofia Alexandra , Namjoshi Gyanesh , Abouelela Youssef , Nguyen Bao , Madziva Lorraine , Zibdeh Omar , Turner Amy , Jones Elaine , May Emily , Mills Martin , Mwadeyi Memory , Cocks Stephanie , Downing Angela , Mansour Ramy , Newman Hannah , McCormick Christina , England Charlotte , Kalita Maggie , Cardinez Francia , El-Shafei Hussein , Jhala Hiral , Williams Sandra , McDonald Shirley , Jitendra Vikram , Henderson Paula , Abernethy Jocelyn , John Martin , Aduse-Poku Maame , Colville Gary , Patel Mitul Mahesh , Shaw Michael , Ali Tariq , Radcliffe Gillian , Lucchese Gianlucca , Nicou Niki , Makondo Edelline , Quinn Jane , Glizevskaja Julia Glizevskaja , Anderson Pamela , Lavorca Leonardo , Smith-Johnson Sophie , Lushpenko-Brown Helen , Gibbison Ben , Hopkins Emma , Bonnick Esther , Irish Jane , Joseph Linta , Gonzalez Maria de las Mercedes Rodriguez , Lambert Penny , Rose Sophie , Watkins David , Walach Joanna , Vohra Hunaid , Alston Peter , Zamvar Vipin , Campbell Anna , Geddes Ailsa , Tucker Garry , Callaghan Marie , Stagg Matthew , Downing-James Nicholas , Glenwright Margaret , Adamson Issy , Ray-Alende Darlington , Kleine-Brueggeney Maren , Stoppe Christian , Catena Daniel , Matschke Maria-Katrin , Rau Nadine , Hellner Nicolas , Ott Sascha , Tahirovic Valida , Karekla Antria , Knierim Jan , Zarbock Alexander , Meersch-Dini Melanie , Strauss Christian , Sadjadi Mahan , von Groote Thilo , Wessels Melissa , Hollenborg Stephanie , Schützenmeister Katrin , Schedding Gereon , Wempe Carola , Al-Attar Nawwar , Hamilton Charlene , Boyd Elizabeth , Lythgoe Claire , Jones Rowen , Parker Marie , Brennan Jessica , Walsh Stephanie , Crossley Anna , Hamer Olivia , MacDonald Steven , Butler Emma , Flemming Jessica , Murphy Gavin J , Sommer Philipp , Schnabel Renate , Lamprou Vasilis , Zheng Yuran , Viswesvaraiah Rajavarma , Barsamyan Sergey , Bedford Jonathan , Adlan Ahmed , Finlay Malcolm , Gibbon Alexa , Sandhu Kully , Giblett Joel , Barnes Jonathan , Juneja Sanjay , Cox Charlie , Akowuah Enoch , Kwok Matt , Astarci Josenir , Canter Ruth , Potter Kimberley , Vale Luke 
Published: August 2024

IMPORTANCE

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.

OBJECTIVE

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.

INTERVENTIONS

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.

MAIN OUTCOMES AND MEASURES

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.

RESULTS

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 &amp;lt;.001).

CONCLUSIONS AND RELEVANCE

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.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT04053816