Cryoablation as Standard Treatment of Atrial Flutter (CASTAF)

Cryoablation as Standard Treatment of Atrial Flutter - Long Term Efficacy and Patient Content

The hypothesis of the present study is to evaluate cryoablation(cooling of the tissue) as standard therapy of common atrial flutter,focusing on efficacy, feasibility, procedure time, and patient content.

The purpose of this study is to determine whether cryoablation, performed only by operators experienced in cryothermic ablation is effective and safe in the treatment of atrial flutter.

Study Overview

• Status: Completed
• Conditions: Atrial Flutter
• Intervention / Treatment: Procedure: Medtronic Freezor Max Cardiac Cryoablation Catheter

Detailed Description

Atrial flutter (AFL), a common atrial tachyarrhythmia may cause significant symptoms and serious adverse effects including embolic stroke, myocardial ischemia and congestive heart failure. Currently, radiofrequency (RF) catheter ablation of the cavotricuspid isthmus (CTI) is considered first-line therapy for treatment of CTI-dependent AFL. However, RF ablation of the CTI is associated with significant pain during lesion delivery. Furthermore, RF ablation can potentially injure cardiac structures adjacent to the CTI such as the AV node, tricuspid valve and right coronary artery. RF ablation can also lead to steam pops, cardiac tamponade and fatal complications have also been reported in association with CTI-ablation. Ablation using cryothermal energy (Cryo) has several potential advantages over RF ablation including greater catheter stability due to adherence to myocardial tissue during applications, reduced risk of thrombus formation, systemic embolization, and lower risk of myocardial perforation due to preservation of tissue architecture.

The investigators have in a prospective randomized, single centre study (CRAFT) investigated efficacy and safety of RF versus Cryo for atrial flutter, and showed that cryoablation is as effective as RF ablation in the short and long term. The patients perceived significantly less pain and required significantly lower doses of analgesia and sedation during cryoablation compared to RF ablation. The study was powered for non-inferiority with 75 patients in each group.

The objective of the present study is to expand the findings from the CRAFT study in a larger cohort of patients, letting only operators experienced in cryothermic CTI ablation use Cryo as standard therapy focusing on efficacy, feasibility, procedure time, and patient content.

To perform an ablation within the study, the electrophysiologist must have a previous experience of a minimum of 25 cryoablations of atrial flutter.

• Study Type: Interventional
• Enrollment (Actual): 193
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Sweden
  • Stockholm, Sweden, SE-14186
    • Karolinska University Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Consecutive patients referred to our institution for ablation therapy of ECG-documented, typical CTI dependent AFL.
• Patients above the age of 18 having symptomatic CTI-dependent AFL documented on a 12-lead ECG with typical ECG appearance of negative saw tooth waves in the inferior limb leads and positive deflections in V1 or positive saw tooth waves in the inferior limb leads and negative deflections in V1.
• Patients with a history of atrial fibrillation will only be included if they have predominant atrial flutter under chronic treatment with class I or III antiarrhythmic agents.

Exclusion Criteria:

1. prior ablation for AFL;
2. atrial flutter related to recently undergone surgery, hyperthyroidism or other severe disease;
3. inability to adhere with the study protocol;
4. pregnancy;
5. predominant atrial fibrillation; and
6. for patients with persistent atrial flutter contraindication to warfarin

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Cryoablation	Procedure: Medtronic Freezor Max Cardiac Cryoablation Catheter; Cryoablation is performed using a sequential application technique point-by-point from the tricuspid annulus to the inferior vena cava. Ablation is performed at a target temperature of -80 ºC. Each application will last for 240 seconds.; Other Names: Cryoablation; CTI ablation

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Efficacy	Clinical success defined as the freedom from atrial flutter evaluated at the 12-month follow-up.	One year after intervention

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Safety	The secondary endpoints will be acute ablation success defined as bidirectional CTI-block, safety assessed by the rate of periprocedural complications, procedure and fluoroscopy times and the level of pain experienced by the patient during the ablation procedure.	During and up to one year after intervention

Collaborators and Investigators

• Sponsor: Karolinska University Hospital
• Investigators: Principal Investigator: Mats Jensen-Urstad, Professor, Karolinska University Hospital

Study record dates

Study Major Dates

• Study Start: June 1, 2012
• Primary Completion (Actual): June 1, 2016
• Study Completion (Actual): June 1, 2016

Study Registration Dates

• First Submitted: May 21, 2012
• First Submitted That Met QC Criteria: May 22, 2012
• First Posted (Estimate): May 23, 2012

Study Record Updates

• Last Update Posted (Estimate): October 6, 2016
• Last Update Submitted That Met QC Criteria: October 5, 2016
• Last Verified: October 1, 2016

More Information

Terms related to this study

• Keywords: Cryoablation; Visual analogue scale; Atrial flutter; Cavotricuspid isthmus
• Additional Relevant MeSH Terms: Pathologic Processes; Heart Diseases; Cardiovascular Diseases; Arrhythmias, Cardiac; Atrial Flutter
• Other Study ID Numbers: KS1