Potassium Supplementation and Prevention of Atrial Fibrillation After Cardiac Surgery: The TIGHT K Randomized Clinical Trial.

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 <.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.

Feasibility of early waking cardiac arrest patients whilst receiving therapeutic hypothermia: The therapeutic hypothermia and early waking (THAW) trial.

AIM: To determine the safety and feasibility of an early (12 h) waking and extubation protocol for out-of-hospital cardiac arrest (OHCA) patients receiving targeted temperature management (TTM). METHODS: This was a single-centre, prospective, non-randomised, observational, safety and feasibility pilot study which included successfully resuscitated OHCA patients, of presumed cardiac cause. Inclusion criteria were: OHCA patients aged over 18 years with a return of spontaneous circulation, who were going to receive TTM33 (TTM at 33 °C for 24 h and prevention of hyperthermia for 72 h) as part of their post cardiac arrest care. Clinical stability was measured against physiological and neurological parameters as well as clinical assessment. RESULTS: 50 consecutive patients were included (median age 65.5 years, 82% male) in the study. Four (8%) patients died within the first twelve hours and were excluded from the final cohort (n = 46). Twenty-three patients (46%) were considered clinically stable and suitable for early waking based on the intention to treat analysis; 12 patients were extubated early based on a variety of clinical factors (21.4 ± 8.6 h) whilst continuing to receive TTM33 with a mean core temperature of 34.2 °C when extubated. Of these, five patients were discharged from the intensive care unit (ICU) <48 h after admission with a mean ICU length of stay 1.8 ± 0.4 days. Twenty-eight patients (56%) were discharged from the ICU with a modified Rankin Score of 0-2. The overall intra-hospital mortality was 50% (n = 25). CONCLUSIONS: It is safe and feasible to wake selected comatose OHCA patients at 12 h, allowing for earlier positive neuro-prognostication and reduced ICU stay.

Is It Feasible and Safe to Wake Cardiac Arrest Patients Receiving Mild Therapeutic Hypothermia After 12 Hours to Enable Early Neuro-Prognostication? The Therapeutic Hypothermia and Early Waking Trial Protocol.

Mild therapeutic hypothermia (MTH 33°C) post out-of-hospital cardiac arrest (OHCA) is widely accepted as standard of care. However, uncertainty remains around the dose and therapy duration. OHCA patients are usually kept sedated±paralyzed and ventilated for the first 24-36 hours, which allows for targeted temperature management, but makes neurological prognostication challenging. The aim of this study is to investigate the feasibility and safety of assessing the unconscious OHCA patient after 12 hours for early waking/extubation while continuing to provide MTH for 24 hours, and fever prevention for 72 hours by using an intravenous temperature management (IVTM) system and established conscious MTH anti-shiver regimens. This is a single-center, prospective, non-randomized observational study that will compare the results of early awakening (at 12 hours) with historical controls. A total of 50 consecutive unconscious survivors of OHCA, treated with MTH, who meet the Therapeutic Hypothermia and eArly Waking (THAW) inclusion criteria will be enrolled. The patient will receive MTH by using IVTM. After 12 hours of MTH, patients will be assessed by using strict clinical criteria to determine suitability for early waking and extubation. Once awake and extubated, MTH will continue for 24 hours with skin counter-warming and anti-shiver regimen followed fever prevention up to 72 hours. All patients will have serial electroencephalogram (EEG), somatic sensory potential, and neuro-biomarkers performed on admission to intensive care unit, 6 and 12 hours, then every 24 hours until 72 hours. The study has been approved by the National Research Ethics Service, Health Research Authority.

Management of refractory bleeding post-cardiopulmonary bypass in an acute heparin-induced thrombocytopenia type II renal failure patient who underwent urgent cardiac surgery with bivalirudin (Angiox®) anticoagulation.

Acute heparin-induced thrombocytopenia (HIT) patients present a myriad of anticoagulation management challenges, in clinical settings where unfractionated heparin (UFH) is the traditional drug of choice. UFH use in cardiac surgery is a known entity that has been subject to rigorous research. Research has, thus, led to its unparalleled use and the development of well-established protocols for cardiac surgery. In comparison to UFH, bivalirudin use for acute HIT patients requiring urgent cardiac surgery with cardiopulmonary bypass (CPB) is still in its infancy. We describe the tailored post-CPB management of refractory bleeding in a 65-year-old infective endocarditis, acute HIT patient with renal failure who underwent urgent aortic valve replacement and mitral valve repair with bivalirudin anticoagulation. A management approach that entailed a combination of continuous venovenous haemofiltration (CVVH), 4-Factor prothrombin complex concentrate (PCC) (Beriplex), recombinant factor VIIa (rFactor VIIa) and desmopressin (DDAVP) were consecutively used post-operatively in theatre. Based on this case study experience, two modifications to institutional protocols are recommended. The first is the use of CVVH in theatre to eliminate bivalirudin in renal failure patients or in patients where bivalirudin elimination is prolonged. Secondly, a 'rescue therapy/intervention' algorithm for the swift identification of refractory bleeding post-CPB is also recommended. Rescue therapy agents, such as a 4-Factor PCCs and rFactor VIIa, should be incorporated into the protocol after a robust evidence-based search and agreement with the haematologist. The aim of these recommendations is to reduce the risk of bleeding associated with bivalirudin use for inexperienced institutions and experienced institutions alike, until larger randomized, controlled studies provide more in-depth knowledge to expand our clinical practice.