Surgical Ablation vs Catheter Ablation in Drug-Refractory AF

November 14, 2011

Updated November 14, 2011 (Orlando, Florida) – A randomized comparison between surgical ablation and radiofrequency catheter ablation for the treatment of antiarrhythmic-drug–refractory atrial fibrillation shows that the surgical approach is superior in achieving freedom from arrhythmias at one year [1]. The minimally invasive surgical approach is not without its drawbacks, however, with investigators reporting a significantly higher procedural adverse-event rate in the surgical ablation arm compared with catheter ablation.

Dr Lucas Boersma

In the study, published online November 14, 2011 in Circulation to coincide with a late-breaking clinical-trials session at the American Heart Association 2011 Scientific Sessions, lead investigator Dr Lucas Boersma (St Antonius Ziekenhuis, Nieuwegein, the Netherlands) and colleagues point out that 67% of the patients included in the trial, known as Atrial Fibrillation Catheter Ablation versus Surgical Ablation Treatment (FAST), had failed a previous catheter-ablation procedure, "which could signify a predisposition to catheter-ablation failure."

"In this population of patients with atrial fibrillation with dilated left atrium and hypertension who had failed a prior catheter ablation, we found that minimally invasive surgical ablation was superior to catheter ablation to achieve freedom from atrial arrhythmias without antiarrhythmic drugs in follow-up to 12 months," said Boersma during a press conference announcing the results. "Surgical ablation was accompanied by a higher adverse-event rate than catheter ablation, and we think this is important for physicians and patients when deciding which type of invasive therapy they need."

Put another way, is there any reason why some of them should have the minimally invasive procedure?

Dr Marc Gillinov

Dr Marc Gillinov (Cleveland Clinic, OH), the scheduled discussant during the late-breaking clinical-trial session, told heartwire that surgical ablation is usually reserved for patients undergoing heart surgery, such as a coronary artery bypass graft surgery.

"The bigger question is what to do with these millions of patients who have atrial fibrillation but who don't need heart surgery," said Gillinov. "Put another way, is there any reason why some of them should have the minimally invasive procedure? Today, in the US, there are probably fewer than 1000 people a year going to the operating room for atrial fibrillation alone. I think we have many other therapies to try first, such as medical therapy and catheter ablation, but as the surgery becomes less invasive, more effective, and supported by more data, I think it could have a role in clinical practice."

The FAST Study

The study included 124 patients with drug-refractory atrial fibrillation with left atrial dilatation and hypertension or failed prior catheter ablation. Of the 124 patients, 63 patients were randomized to catheter ablation and 61 patients were randomized to surgical ablation. The catheter-ablation procedure consisted of pulmonary vein isolation with optional lesions created at the operator's discretion. The surgical approach consisted of radiofrequency isolation of the pulmonary veins, ganglionated plexi ablation, and left atrial appendage excision, with additional lesions as needed.

Efficacy End Points for Catheter and Surgical Ablation

Freedom of left atrial arrhythmias Catheter ablation, n=63 (%) Surgical ablation, n=61 (%) p
Overall, 12 mo 36.5 65.6 0.002
Overall, 12 mo, allowing antiarrhythmic drugs 42.9 78.7 <0.0001
Overall, 6 mo 57.1 82.0 <0.0001
Permanent atrial fibrillation 35.1 68.9 0.0047
Persistent atrial fibrillation 36.0 56.0 0.3411
Failed prior catheter ablation 36.8 68.2 0.0089
Left atrial dilatation and/or hypertension 36.0 58.8 0.3411

At 12 months, 36.5% of patients treated with catheter ablation were free from left atrial arrhythmias lasting longer than 30 seconds without the use of antiarrhythmic drugs, whereas 65.6% of patients treated surgically were free from left atrial arrhythmias (p=0.002). In terms of safety, 34.4% of patients treated with surgical ablation had an adverse event, and this was driven largely by an increase in procedural events such as pneumothorax and major bleeding. In the catheter-ablation arm, 15.9% of patients had an adverse event, including one case of transient ischemic attack (TIA)/stroke and one case of pericardial effusion/tamponade.

To heartwire , Gillinov said that depending on the center, anywhere from 20% to 60% of patients will have recurrent atrial fibrillation and will need to be treated with medical therapy or a repeat catheter ablation, and this is the first randomized trial comparing surgical ablation and catheter ablation for the treatment of atrial fibrillation in complex patients. He pointed out that patients in the surgical arm had their left atrial appendage removed, and this is thought to be beneficial in reducing the risk of stroke. He added that the increased rate of pneumothorax, or fluid in the lungs, is not a serious side effect for surgeons and can be treated quite easily.

The MANTRA Study

Dr Jens Cosedis Nielsen

A second study in atrial fibrillation also tackled an aggressive form of treatment, with investigators testing the safety and efficacy of catheter ablation as a first-line therapy in patients with paroxysmal atrial fibrillation. The study, also presented during the late-breaking clinical-trials session, and known as MANTRA-PAF, compared radiofrequency ablation with antiarrhythmic drug therapy in 294 patients.

After two years, investigators, led by Dr Jens Cosedis Nielsen (Technical University of Denmark, Aarhus), observed a significant reduction in atrial-fibrillation burden and occurrence of symptomatic atrial fibrillation, as well as a reduction in the burden and occurrence of atrial fibrillation of any kind. They did not, however, observe a significant reduction in the cumulative burden of atrial fibrillation between the two treatment arms. Physical quality-of-life scores were significantly improved with catheter ablation.

If we're going to start offering an invasive procedure to patients with what we consider a benign arrhythmia, where the issue is on quality of life, that therapy has to be very, very safe.

In the US, the American College of Cardiology Foundation/American Heart Association/Heart Rhythm Society guidelines state that catheter ablation is a class I indication (level of evidence A) when performed at experienced centers to maintain sinus rhythm in selected patients with significantly symptomatic paroxysmal atrial fibrillation. These patients must also have failed treatment with an antiarrhythmic drug, as well as have normal or mildly dilated left atria, normal or mildly reduced left ventricular function, and no severe pulmonary disease. In Europe, the guidelines differ, with the Europeans stating that catheter ablation can be considered as an initial therapy in selected patients when performed by experienced operators.

Dr William Stevenson

Speaking with the media, Dr William Stevenson (Brigham and Women's Hospital, Boston, MA), who was not part of the trial, said MANTRA includes a highly symptomatic patient cohort, with patients often complaining of palpitations, dizziness, and diminished quality of life.

"We know that a patient with paroxysmal atrial fibrillation should receive therapy to protect them from stroke and also requires therapy to control their heart rate when they are in atrial fibrillation," said Stevenson. "As long as we take care of those two things, the risk to them from their arrhythmia is very low. So we're really dealing with quality-of-life issues when we consider different therapies to maintain sinus rhythm."

Stevenson noted that the efficacy of antiarrhythmic drug therapy in MANTRA was higher than observed in previous trials but that the crossover rate was high, with 36% of patients in the drug arm undergoing catheter ablation. More important, he noted that there was one death, three cases of cardiac tamponade, and one case of pulmonary stenosis. Historically, catheter ablation has a mortality rate of 0.1%, a 0.5% risk of thromboembolic events/stroke, and a 0.5% to 1.0% risk of cardiac tamponade.

"The major issue, if we're going to start offering an invasive procedure to patients with what we consider a benign arrhythmia, where the issue is on quality of life, that therapy has to be very, very safe."