Catheter Ablation versus Thoracoscopic Surgical Ablation in Long Standing Persistent Atrial Fibrillation (CASA-AF): study protocol for a randomised controlled trial

Abstract

BackgroundAtrial fibrillation is the commonest arrhythmia which raises the risk of heart failure, thromboembolic stroke, morbidity and death. Pharmacological treatments of this condition are focused on heart rate control, rhythm control and reduction in risk of stroke. Selective ablation of cardiac tissues resulting in isolation of areas causing atrial fibrillation is another treatment strategy which can be delivered by two minimally invasive interventions: percutaneous catheter ablation and thoracoscopic surgical ablation. The main purpose of this trial is to compare the effectiveness and safety of these two interventions.Methods/designCatheter Ablation versus Thoracoscopic Surgical Ablation in Long Standing Persistent Atrial Fibrillation (CASA-AF) is a prospective, multi-centre, randomised controlled trial within three NHS tertiary cardiovascular centres specialising in treatment of atrial fibrillation. Eligible adults (n = 120) with symptomatic, long-standing, persistent atrial fibrillation will be randomly allocated to either catheter ablation or thoracoscopic ablation in a 1:1 ratio. Pre-determined lesion sets will be delivered in each treatment arm with confirmation of appropriate conduction block. All patients will have an implantable loop recorder (ILR) inserted subcutaneously immediately following ablation to enable continuous heart rhythm monitoring for at least 12 months. The devices will be programmed to detect episodes of atrial fibrillation and atrial tachycardia ≥ 30 s in duration. The patients will be followed for 12 months, completing appropriate clinical assessments and questionnaires every 3 months. The ILR data will be wirelessly transmitted daily and evaluated every month for the duration of the follow-up. The primary endpoint in the study is freedom from atrial fibrillation and atrial tachycardia at the end of the follow-up period.DiscussionThe CASA-AF Trial is a National Institute for Health Research-funded study that will provide first-class evidence on the comparative efficacy, safety and cost-effectiveness of thoracoscopic surgical ablation and conventional percutaneous catheter ablation for long-standing persistent atrial fibrillation. In addition, the results of the trial will provide information on the effects on patients’ quality of life.Trial registrationISRCTN Registry, ISRCTN18250790. Registered on 24 April 2015.Electronic supplementary materialThe online version of this article (10.1186/s13063-018-2487-9) contains supplementary material, which is available to authorized users.

Catheter ablation vs. thoracoscopic surgical ablation in long-standing persistent atrial fibrillation: CASA-AF randomized controlled trial

“…The published protocol was in accordance with the Interventional Trials (SPIRIT) 2013 statement. 15 , 16 The conduct of the study was overseen by two independent bodies, the Data Monitoring and the Trial Steering Committees.…”

“…Procedure details and pre- and post-ablation patient management have been previously published in the trial protocol. 16 In SA, radiofrequency ablation was performed under direct vision starting with pulmonary vein isolation (PVI), then GP ablation, followed by linear roof and inferior line ablation to create a posterior wall box lesion. The LAA was then excluded using the AtriClip ® LAA excluder system (AtriCure).…”

Left Atrial Function Predicts Atrial Arrhythmia Recurrence Following Ablation of Long-Standing Persistent Atrial Fibrillation

“…The protocol of the CASA-AF trial and the primary outcome analysis were published previously. 19 , 20 The study was approved by the National Health Research Authority (15/SC/0023), and all participants gave written consent. Included patients were >18 years old with long-standing persistent AF (>12 months’ duration), European Heart Rhythm Association symptom score >2, left ventricular ejection fraction ≥40%, suitable for either ablation procedure.…”

Thoracoscopic surgical ablation versus catheter ablation as first-line treatment for long-standing persistent atrial fibrillation: the CASA-AF RCT

“…The study protocol was developed in accordance with current guidelines for clinical trials 37,38 and was published in 2018. 39 The conduct of the study was overseen by an independent Data Monitoring Committee (DMC) and an independent Trial Steering Committee (TSC), which both met twice per year throughout the study.…”