Catheter Ablation vs. Antiarrhythmic Drug Therapy for Atrial Fibrillation - CABANA Pilot Study

Description:

The recently published ThermoCool AF study demonstrated the superiority of catheter ablation with pulmonary vein isolation (PVI) over antiarrhythmic drugs (AAD) in the management of patients with symptomatic atrial fibrillation (AF), who had failed at least one AAD. The CABANA pivotal trial tested the hypothesis that primary catheter ablation for the elimination of AF is superior to state-of-the-art drug therapy for reducing recurrent AF in high-risk patients.

Hypothesis:

Catheter ablation would be superior to medical management in the treatment of recurrent AF in high-risk patients.

Study Design

  • Parallel

Patients Enrolled: 60
NYHA Class: II or III (36%)
Mean Follow Up: 12 months
Mean Patient Age: Median age: 61 years
Female: 23
Mean Ejection Fraction: 55%

Patient Populations:

• ≥2 paroxysmal AF episodes (≥1 hour) over 4 months or ≥1 persistent AF episode (>1 week)

• ≥65 years of age, or <65 years with ≥1 risk factor:
  • Hypertension
  • Diabetes
  • Heart failure
  • Prior cerebrovascular accident or transient ischemic attack
  • Left atrial size >5.0 cm (volume index ≥40 cc/m2)
  • Ejection fraction ≤35%

• Eligible for ablation and ≥2 rhythm control and/or ≥3 rate control drugs

Primary Endpoints:

  • AF recurrence

    Secondary Endpoints:

    • Complications with therapy
    • Change in left atrial volume and morphology
    • Recurrent hospitalization
    • Quality-of-life outcomes

    Drug/Procedures Used:

    Catheter ablation was performed percutaneously, with isolation of all four pulmonary veins (PVI). Additional adjunctive linear or circumferential ablation was conducted as necessary. In the medical management arm, patients could be treated with rhythm (16%), rate control (13%), or both (71%).

Principal Findings:

A total of 60 patients were randomized, in which 29 patients were randomized to catheter ablation, and 31 patients to medical management. Baseline characteristics were fairly similar between the two groups. About 80% had hypertension, 18% had diabetes, and 17% had underlying cardiomyopathies. About 35% had coronary artery disease, and 36% had class II or III heart failure. Paroxysmal AF was noted in 32%, and 68% had persistent or long-standing persistent AF. Prior antiarrhythmic drugs had been tried in 30%, with 25% having failed one AAD. About 23% of patients had a history of atrial flutter. About 39% of the patients had a CHADS2 score of ≥2.

The incidence of freedom from symptomatic AF after the blanking period was significantly higher in the catheter ablation arm, as compared with AAD (65% vs. 41%, hazard ratio [HR] 0.46, 95% confidence interval [CI] 0.21-0.99, p = 0.03). However, the incidence of any AF, atrial flutter, or atrial tachycardia was similar between the two arms (66% vs. 72%, HR 0.69, 95% CI 0.37-1.32, p = 0.26). About 13% of patients crossed over from the AAD arm to the catheter ablation arm over the duration of follow-up, and 21% of patients in the catheter ablation arm needed at least one other ablation procedure.

Adverse events after catheter ablation included moderate PV stenosis in one patient; no cases of severe PV stenosis. In addition, two patients developed an AV fistula or a pseudoaneurysm, with no atrial esophageal fistulas.

Interpretation:

The results of the CABANA pilot study indicate that catheter ablation is associated with a reduction in symptomatic AF in high-risk patients, as compared with AAD. In this small group of patients, there was no difference in the incidence of AF, atrial flutter, or atrial tachycardia between the two groups. Adverse event rates were low, including the incidence of PV stenosis.

The results of the CABANA pilot study will be used for designing the CABANA pivotal study.

References:

Presented by Dr. Douglas Packer at the ACC.10/i2 Summit, Atlanta, GA, March 2010.

Clinical Topics: Arrhythmias and Clinical EP, Heart Failure and Cardiomyopathies, Prevention, Vascular Medicine, Atherosclerotic Disease (CAD/PAD), SCD/Ventricular Arrhythmias, Atrial Fibrillation/Supraventricular Arrhythmias, Acute Heart Failure, Hypertension

Keywords: Aneurysm, False, Coronary Artery Disease, Stroke, Ischemic Attack, Transient, Pulmonary Veins, Constriction, Pathologic, Tachycardia, Cardiomyopathies, Heart Failure, Esophageal Fistula, Catheter Ablation, Hypertension, Diabetes Mellitus, Atrial Flutter


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