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Catheter Versus Thoracoscopic Surgical Ablation Strategy in Persistent Atrial Fibrillation (CASA-AF)

The recruitment status of this study is unknown. The completion date has passed and the status has not been verified in more than two years.
Verified June 2011 by Royal Brompton & Harefield NHS Foundation Trust.
Recruitment status was:  Enrolling by invitation
Information provided by:
Royal Brompton & Harefield NHS Foundation Trust Identifier:
First received: June 28, 2011
Last updated: June 29, 2011
Last verified: June 2011

Atrial fibrillation(AF)is the commonest arrhythmia worldwide and can lead to significant morbidity and mortality, posing an increasing public health burden. Restoration of sinus rhythm (SR) is the preferred strategy in symptomatic patients but outcomes with anti-arrhythmic drugs (AAD) are poor. The alternatives to AAD are two-fold.Firstly, catheter ablation (CA)- a technique that uses catheters (thin tubes) to deliver small 'heat lesions' to areas of the heart to eliminate AF. Secondly, surgical ablation, where multiple incisions are made in the atria to restore SR. Long term results from this traditional surgical approach are excellent however as it is technically difficult open-heart procedure with significant morbidity and mortality, it is seldom used.

CA is very effective in restoring SR in the early stages of AF when it is a paroxysmal (intermittent) rhythm disturbance. If not treated at this stage AF inevitably evolves into a more persistent or permanent state and becomes more difficult to treat with CA. Therefore, the optimum approach to treat patients with symptomatic long standing persistent AF has yet to be determined and remains a key area of on-going research.

New minimally invasive, thoracoscopically assisted surgical(closed-heart)approaches have recently developed which ablate a wide area around the pulmonary veins, and may offer advantages over the best current strategies in CA. There are also clear advantages for patients with greater safety and less discomfort when compared to traditional surgical open-heart procedures.

At present there is small amount of encouraging data on this thoracoscopic surgical technique but there is no data comparing these two modalities of treatment in persistent AF patients. The investigators therefore wish to prospectively investigate the safety and efficacy of this thoracoscopic surgical technique and compare with CA in this group of patients. MRI scanning will also be used to visualise the effects of ablation by analysis of scar formation.

The study hypothesises that thoracoscopics surgical ablation is a

Condition Intervention
Persistent Atrial Fibrillation
Procedure: Thoracoscopically Assisted Surgical Ablation
Procedure: Catheter Ablation

Study Type: Interventional
Study Design: Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Masking: Single Blind (Outcomes Assessor)
Primary Purpose: Treatment
Official Title: A Study to Assess Catheter Ablation Versus Thoracoscopically Assisted Surgical Ablation in Persistent Atrial Fibrillation

Resource links provided by NLM:

Further study details as provided by Royal Brompton & Harefield NHS Foundation Trust:

Primary Outcome Measures:
  • Freedom from atrial tachyarrhythmias at 12 months. [ Time Frame: 12 months ]
    Freedom from atrial tachyarrhythmias at 12 months which will be analysed with or without anti-arrhythmic drugs (AAD). Monitoring will be undertaken with ambulatory ECG monitoring in compliance with latest international guidelines.

Secondary Outcome Measures:
  • Freedom from atrial tachyarrhythmias at 12 months from a single procedure on/off AAD; [ Time Frame: 12 months ]
    Only 1 re-do procedure is allowed in study time frame. But this outcome will look at single procedure success in both arms at 12 months.

  • Change in AF symptom score [ Time Frame: Various time points 0,3,6,9,12 months ]
    Using recognised AF symptom score scale

  • Integrity of ablation lesion after index procedure at 3 months (as assessed by MRI if in SR +/- electrophysiologically if redo procedure is undertaken for atrial arrhythmia recurrence); [ Time Frame: 3 months ]
    Using MRI +/- electrophysiological techniques.

  • Freedom of serious adverse events (stroke, myocardial infarction, emergency surgery, death) immediately after the procedure and during follow-up. [ Time Frame: 12 months ]
  • Cost analysis (procedural and hospital stay costs). [ Time Frame: 12 months ]
    Top down cost analysis

Estimated Enrollment: 60
Study Start Date: April 2011
Estimated Study Completion Date: October 2013
Estimated Primary Completion Date: October 2013 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: Thoracoscopically Assisted Surgical Ablation
This arm will have an index thoracoscopically assisted surgical ablation.
Procedure: Thoracoscopically Assisted Surgical Ablation
Surgical AF ablation including pulmonary vein isolation, gananglionated plexi ablation +/- LAA excision/exclusion.
Active Comparator: Catheter Ablation
This is an active comparator arm where study subjects will undergo conventional catheter ablation.
Procedure: Catheter Ablation
In this arm, study subjects will undergo conventional catheter ablation as their index procedure. This will include pulmonary vein isolation, linear and electrogram based ablation.

Detailed Description:

This will be a pilot, prospective, observational study of catheter ablation compared with thoracoscopically assisted, surgical ablation strategies using a case control design.

The study population will be patients between the ages of 18 and 80 with symptomatic long-standing persistent atrial fibrillation (≥1≤5 years) and good left ventricular function where at least one anti-arrhythmic drug (AAD) has failed, or where such drugs are contraindicated or not tolerated.

Thoracoscopically Assisted Surgical Ablation Group Patients assigned to this group will undergo minimally invasive, thoracoscopically assisted, surgical ablation to isolate the pulmonary veins (PVI) using a radiofrequency (RF) clamp device. This will include ganglionated plexi ablation +/- LAA excision/exclusion.

Catheter Ablation Group Patients will undergo pulmonary vein isolation, linear and electrogram based ablation.

Recurrences Only one redo procedure is allowed for atrial tachyarrhythmia recurrences in the 12 month follow-up period.


Ages Eligible for Study:   18 Years to 80 Years   (Adult, Senior)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes

Inclusion Criteria:

  1. Age ≥18 years and ≤ 80
  2. Symptomatic persistent AF (≥1≤5 years), refractory to at least 1 AAD and/or DCCV
  3. Patient is legally competent and willing and able to sign informed consent form
  4. Patient is willing and able to adhere to follow up visit protocols for the duration of the study

Exclusion Criteria:

  1. Left ventricular ejection fraction < 40%
  2. Cardiovascular implantable electronic device (contraindicates MRI imaging)
  3. Contraindication to anticoagulation
  4. Thrombus in the LA despite anticoagulation
  5. CVA within the previous 6 months
  6. Previous thoracic & cardiac surgery (including interventions for AF such as Cox-maze procedure)
  7. Prior LA catheter ablation with the intention to treat AF
  8. Prior AV nodal ablation
  9. Patients actively participating in another research study will be not be permitted to enrol. Patients who have been involved with other research studies will be able to participate after a minimum period of 3 months after completion of prior study follow up.
  10. Co-morbid condition that in opinion of investigator confers undue risk of GA or thoracoscopic surgery.
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Please refer to this study by its identifier: NCT01385358

United Kingdom
Royal Brompton & Harefield NHS Foundation Trust
London, Greater London, United Kingdom, SW3 6NP
Sponsors and Collaborators
Royal Brompton & Harefield NHS Foundation Trust
Principal Investigator: Tom Wong, MD Royal Brompton & Harefield NHS Foundation Trust
  More Information

Responsible Party: Wendy Butcher / Head of Research Governance and Performance, Royal Brompton & Harefield NHS Foundation Trust Identifier: NCT01385358     History of Changes
Other Study ID Numbers: 2011CI004B
11/SC/0032 ( Other Identifier: Oxfordshire REC A Committee )
Study First Received: June 28, 2011
Last Updated: June 29, 2011

Additional relevant MeSH terms:
Atrial Fibrillation
Arrhythmias, Cardiac
Heart Diseases
Cardiovascular Diseases
Pathologic Processes processed this record on April 28, 2017