Atrial Flutter
Conditions
Keywords
Type 1 Atrial Flutter, Typical Atrial Flutter, Arrhythmias, Cardiac, Heart Diseases, Cardiovascular Diseases
Brief summary
The purpose of the BLOCk-CTI study is to evaluate the safety and effectiveness of the Blazer® Open-Irrigated Ablation Catheter for the treatment of sustained or recurrent type 1 atrial flutter. This study will compare outcomes in patients treated with the Blazer® Open-Irrigated Ablation Catheter to outcomes in patients treated with open-irrigated radiofrequency ablation catheters that have received FDA market approval for the treatment of type 1 atrial flutter.
Detailed description
The BLOCk-CTI study is a prospective, multicenter, single blind, 1:1 randomized study. The study is designed to demonstrate that the safety and effectiveness of the Blazer® Open-Irrigated Ablation Catheter are non-inferior to the safety and effectiveness of the control catheters. In this study, the control catheters are open-irrigated radiofrequency ablation catheters that have received FDA market approval for the treatment of type 1 atrial flutter. (Biosense Webster ThermoCool® ablation catheters (NaviStar™, EZ Steer, or SF) or St. Jude Medical ablation catheters (Therapy™ Cool Path™ or Safire BLU™).
Interventions
DEVICEBlazer® Open-Irrigated Ablation Catheter
Blazer® Open-Irrigated Ablation Catheter
DEVICEControl Catheter
Open-irrigated radiofrequency ablation catheters that have received FDA market approval for the treatment of type 1 atrial flutter
Sponsors
Boston Scientific Corporation
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
SINGLE (Subject)
Masking description
Subject was not told by investigator if device used was Investigational or Control. The subject could ask the investigator at end of study at 3 months if they wanted to know which device was used.
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
* At least 1 documented episode of type 1 atrial flutter in the 180 days (6 months) preceding enrollment documented by 12-lead ECG, Holter monitor, rhythm strip, or transtelephonic monitor * Patients are clinically indicated for catheter ablation * Patients receiving oral anti-arrhythmic drug therapy (class I or class III) for a tachyarrhythmia other than type 1 atrial flutter must be controlled on the anti-arrhythmic drug for a minimum of 30 days prior to enrollment. If type 1 atrial flutter was documented prior to the development of other tachyarrhythmias, this 30-day period is not required. * Age 18 or above, or of legal age to give informed consent specific to state and national law * Patients are competent and willing to provide written informed consent to participate in the study and agree to comply with follow-up visits and evaluation
Exclusion criteria
* Any prior right atrial cavo-tricuspid isthmus ablation or any cardiac ablation for non-atrial flutter arrhythmias within 90 days prior to enrollment * Cardiac surgery within 90 days prior to enrollment * Myocardial infarction within 60 days prior to enrollment * Current unstable angina * Patients who cannot have anti-arrhythmic drugs (class I and class III) prescribed for the treatment of type 1 atrial flutter stopped on the day of the procedure * Patients regularly prescribed amiodarone within the 120 days (4 months) prior to enrollment * Documented atrial or ventricular tumors, clots, thrombus, or have a known clotting disorder within 90 days prior to enrollment * Implantation of permanent leads of an implantable device in or through the right atrium within 90 days prior to enrollment * Direct remedial cause of atrial flutter (e.g. thyroid disease, pericarditis, pulmonary embolic disease) * Atypical or scar-based flutter * Patients with New York Heart Association Class III at the time of enrollment or New York Heart Association Class IV heart failure within 90 days prior to enrollment * Patients with an ejection fraction less than 30% within 90 days prior to enrollment * Clinically significant structural heart disease (including tricuspid valve regurgitation, tricuspid valve stenosis, tricuspid valve replacement, Ebstein's anomaly, or other congenital heart disease) that would preclude catheter introduction and placement, as determined by the Investigator * Any cerebral ischemic event (including transient ischemic attacks) within 180 days prior to enrollment * Contraindication to anticoagulation therapy based upon published guidelines * Creatinine greater than 2.5 mg/dl or creatinine clearance less than 30 mL/min within 90 days prior to enrollment * Any other significant uncontrolled or unstable medical condition (e.g. sepsis, acute metabolic illness) * Enrolled in any concurrent study without BSC written approval * Women who are pregnant or plan to become pregnant within the course of their participation in the investigation * Life expectancy less than or equal to 2 years (730 days) per physician opinion
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Procedure-related Complication-free Rate | 7 days post-procedure | A procedure-related complication is defined as an adverse event that results in death, a life-threatening complication, or a persistent or significant disability/incapacity or required intervention to prevent a permanent impairment of a body function or damage to a body structure. All adverse events related to the investigational or control devices or ablation procedure will be considered procedure-related events. |
| Acute Success Rate | 30 minutes after the last radiofrequency application in the cavo-tricuspid isthmus | Acute success is defined as demonstration of bidirectional cavo-tricuspid isthmus block (ie, lack of electrophysiological conduction through the isthmus) 30 minutes after the last radiofrequency application in the cavo-tricuspid isthmus with the investigational or control catheter only. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Chronic Success Rate: All Treated Patients | 3 months post-procedure | Chronic success is defined as freedom from recurrence of type 1 atrial flutter at 3-months post-procedure for all treated patients. |
| Chronic Success Rate: Acute Success Patients | 3-months post-procedure | Chronic success is defined as demonstration of acute success and freedom from recurrence of type 1 atrial flutter at 3-months post-procedure. Only randomized patients with acute procedural success will be included in this endpoint. |
Countries
United States
Participant flow
Recruitment details
Subjects were recruited from referring physicians for ablation for type 1 atrial flutter
Pre-assignment details
Subjects were excluded if there were no documented episodes of atrial flutter or inclusion criteria were not met. Roll-in subjects were not randomized.
Participants by arm
| Arm | Count |
|---|---|
| Randomized Blazer® Open-Irrigated Ablation Catheter Patients randomized to treatment with the Blazer® Open-Irrigated Ablation Catheter | 125 |
| Randomized Control Catheter Patients randomized to treatment with an open-irrigated radiofrequency ablation catheter that has received FDA market approval for the treatment of type 1 atrial flutter
Control Catheter: Open-irrigated radiofrequency ablation catheters that have received FDA market approval for the treatment of type 1 atrial flutter | 125 |
| Roll-In Blazer® Open-Irrigated Ablation Catheter The use of the Blazer-Open Irrigated Catheter was required after the second study suspension. Previously enrolled subjects prior to suspension were also classified as Roll-in subjects; not counted in endpoint analysis. | 30 |
| Roll-In Control Catheter The use of the Control Catheter was optional after the second study suspension in a Roll-in subject. Previously enrolled subjects prior to suspension were also classified as Roll-in subjects; not counted in endpoint analysis | 17 |
| Not Randomized to Any Treatment Group Subjects not Randomized to any treatment group and were not Roll-in subjects | 5 |
| Total | 302 |
Withdrawals & dropouts
| Period | Reason | FG000 | FG001 | FG002 | FG003 | FG004 |
|---|---|---|---|---|---|---|
| Overall Study | Attempts | 6 | 4 | 1 | 2 | 0 |
| Overall Study | Death | 1 | 0 | 0 | 0 | 0 |
| Overall Study | intents | 10 | 10 | 1 | 3 | 0 |
| Overall Study | Lost to Follow-up | 1 | 1 | 0 | 0 | 0 |
| Overall Study | Protocol Violation | 1 | 4 | 0 | 0 | 5 |
| Overall Study | Withdrawal by Subject | 2 | 0 | 0 | 0 | 0 |
Baseline characteristics
| Characteristic | Randomized Blazer® Open-Irrigated Ablation Catheter | Randomized Control Catheter | Roll-In Blazer® Open-Irrigated Ablation Catheter | Roll-In Control Catheter | Not Randomized to Any Treatment Group | Total |
|---|---|---|---|---|---|---|
| Age, Continuous | 65 years STANDARD_DEVIATION 11 | 66 years STANDARD_DEVIATION 10 | 69 years STANDARD_DEVIATION 10 | 66 years STANDARD_DEVIATION 9 | 72 years STANDARD_DEVIATION 11 | 65.73 years STANDARD_DEVIATION 10.54 |
| Region of Enrollment United States | 125 participants | 125 participants | 30 participants | 17 participants | 5 participants | 302 participants |
| Sex: Female, Male Female | 23 Participants | 29 Participants | 4 Participants | 4 Participants | 2 Participants | 62 Participants |
| Sex: Female, Male Male | 102 Participants | 96 Participants | 26 Participants | 13 Participants | 3 Participants | 240 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk | EG002 affected / at risk | EG003 affected / at risk | EG004 affected / at risk |
|---|---|---|---|---|---|
| deaths Total, all-cause mortality | 1 / 125 | 0 / 125 | 0 / 30 | 0 / 17 | 0 / 5 |
| other Total, other adverse events | 50 / 109 | 61 / 111 | 16 / 28 | 7 / 12 | 0 / 5 |
| serious Total, serious adverse events | 7 / 109 | 2 / 111 | 5 / 28 | 2 / 12 | 0 / 5 |
Outcome results
Primary
Acute Success Rate
Acute success is defined as demonstration of bidirectional cavo-tricuspid isthmus block (ie, lack of electrophysiological conduction through the isthmus) 30 minutes after the last radiofrequency application in the cavo-tricuspid isthmus with the investigational or control catheter only.
Time frame: 30 minutes after the last radiofrequency application in the cavo-tricuspid isthmus
Population: The primary outcome analysis is for a further subset of Randomized subjects only who underwent RF ablation; 220 subjects out of the total 302 subjects. All is consistent with the approved statistical analysis plan and information publicly available in the FDA Summary of Safety and Effectiveness Data (SSED) and BSC labeling, the Directions for Use.
| Arm | Measure | Value (NUMBER) |
|---|---|---|
| Blazer® Open-Irrigated Ablation Catheter | Acute Success Rate | 87.2 percentage of success |
| Control Catheter | Acute Success Rate | 89.2 percentage of success |
Primary
Procedure-related Complication-free Rate
A procedure-related complication is defined as an adverse event that results in death, a life-threatening complication, or a persistent or significant disability/incapacity or required intervention to prevent a permanent impairment of a body function or damage to a body structure. All adverse events related to the investigational or control devices or ablation procedure will be considered procedure-related events.
Time frame: 7 days post-procedure
Population: The primary outcome analysis is for a further subset of Randomized subjects only who underwent RF ablation; 220 subjects out of the total 302 subjects. All is consistent with the approved statistical analysis plan and information publicly available in the FDA Summary of Safety and Effectiveness Data (SSED) and BSC labeling, the Directions for Use.
| Arm | Measure | Value (NUMBER) |
|---|---|---|
| Blazer® Open-Irrigated Ablation Catheter | Procedure-related Complication-free Rate | 92.7 percentage of subjects |
| Control Catheter | Procedure-related Complication-free Rate | 98.2 percentage of subjects |
Comparison: Note that analysis of the primary outcome was conducted for Randomized subjects only as prespecified in the study protocol. This is consistent analysis publicly available in the Summary of Safety and Effectiveness Data (SSED).
Secondary
Chronic Success Rate: Acute Success Patients
Chronic success is defined as demonstration of acute success and freedom from recurrence of type 1 atrial flutter at 3-months post-procedure. Only randomized patients with acute procedural success will be included in this endpoint.
Time frame: 3-months post-procedure
Population: The secondary outcome analysis is for a further subset of Randomized subjects only who underwent RF ablation and classified as acute success; 194 of the total 302 subjects. All consistent with approved statistical analysis plan and information publicly available in the FDA SSED and BSC the Directions for Use.
| Arm | Measure | Value (NUMBER) |
|---|---|---|
| Blazer® Open-Irrigated Ablation Catheter | Chronic Success Rate: Acute Success Patients | 85.3 percentage of chronic success |
| Control Catheter | Chronic Success Rate: Acute Success Patients | 89.9 percentage of chronic success |
Secondary
Chronic Success Rate: All Treated Patients
Chronic success is defined as freedom from recurrence of type 1 atrial flutter at 3-months post-procedure for all treated patients.
Time frame: 3 months post-procedure
Population: The secondary outcome analysis is for a subset of Randomized subjects only who underwent RF ablation; 220 subjects out of the total 302 subjects. All is consistent with the approved statistical analysis plan and information publicly available in the FDA Summary of Safety and Effectiveness Data (SSED) and BSC labeling, the Directions for Use.
| Arm | Measure | Value (NUMBER) |
|---|---|---|
| Blazer® Open-Irrigated Ablation Catheter | Chronic Success Rate: All Treated Patients | 74.3 percentage of subjects |
| Control Catheter | Chronic Success Rate: All Treated Patients | 80.2 percentage of subjects |