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