AF Ablation Successes, Shortfalls Revealed in European Registry

August 29, 2012

August 28, 2012 (Munich, Germany) — About three-fourths of patients who underwent catheter ablation for atrial fibrillation (AF) in a European registry study were free of arrhythmia recurrences at one year [1]. Almost 90% of patients had been symptomatic before AF ablation; a little less than half had symptoms a year after the procedure.

Also, 65% of the 1300 patients included in the 12-month follow-up analysis from the Atrial Fibrillation Ablation Pilot Study at the end were still taking vitamin-K antagonists or some other kind of anticoagulant, and 32% were on antiarrhythmic agents.

Many patients who were scored as high risk for embolic events had gone off anticoagulants during the follow-up, while many considered low embolic risk stayed on the drugs.

And overall, after AF ablation many patients were not followed by ECG, Holter monitoring, or some other kind of rhythm monitoring judiciously enough, some say, to allow a decision on anticoagulant withdrawal.

Recommendations-Practice Gap

The European electrophysiology community probably won't be too surprised by the findings, Dr Elena Arbelo (Hospital Clínic Universitari de Barcelona, Spain) told heartwire before formally presenting the registry analysis here at the European Society of Cardiology (ESC) 2012 Congress. They generally don't attempt to stop antiarrhythmic or anticoagulant therapy after three months in the apparent absence of recurrences, as the guidelines recommend. Rather, she said, "we usually individualize according to the person we have in front of us."

That said, according to Arbelo, there's "a gap between recommendations and actual clinical practice" that should be taken into account when assessing management strategies for AF. Also, she noted, success rates for the procedure in the registry are somewhat lower than would have been predicted from clinical trials.

Centers from the 10 European countries contributing to the registry were required to have at least a 50-patient annual AF-ablation case volume; represented were Belgium, the Czech Republic, Denmark, France, Germany, Greece, Italy, the Netherlands, Poland, and Spain.

Mortality and Complication Rates, 1400 Patients Undergoing AF Ablation

Complications/events In-hospital (%) Postdischarge (%)
All complications 7.7 2.6
Major complications 1.7 0.8
Mortality 0.07 0.31
CV mortality 0.07 0.16

About half of the 1300 patients in the current analysis had hypertension at baseline, about one-third were older than 65 years, and 38% had lone atrial fibrillation.

The one-year rate of treatment success was defined as survival free from documented atrial arrhythmia, with or without antiarrhythmic drugs, starting from the end of the third month to 12 months. Recurrences in the first three months were not counted as failures.

The rate of AF ablation success was 73.7%; 88% of patients were in sinus rhythm at 12 months.

The readmission rate was 30%, which included admissions for AF, atrial flutter, or atrial tachycardia in 21% and from other CV causes in 4.4%.

Four patients died during the year, including at least one from hemorrhagic stroke. Complications were few and consisted primarily of cerebrovascular events or vascular injury from the catheter procedure, according to Arbelo.

Change in Prevalence of Potentially AF-Related Signs and Symptoms Over One-Year Follow-up

Event Baseline (%) 12 months (%)
Palpitations 72.3 34.3
Fatigue 41.8 12.6
Dyspnea 37.6 12.8
Dizziness 13.7 3.2
Chest pain 10.4 4.8
None 13.1 54.9

As the featured discussant following Arbelo's formal presentation of the registry, Dr Christophe Leclercq (Centre Cardio-Pneumologique, Rennes, France) noted that the risk of complications from AF ablation was comparable to what has been observed in survey analyses, but higher than in single-center studies. In particular, the complication rate is very low after discharge, but "not negligible during the perioperative phase."

Postablation Monitoring for Recurrence Rule-Out

The prominent gap between recommendations and practice in patient follow-up monitoring, according to Arbelo, was unexpected. Just over half the patients underwent Holter monitoring during the follow-up year, despite guidelines calling for clinical and Holter follow-up at least every six months to rule out AF recurrence. About 77%, she noted, reported to the center where they had undergone the ablation and received surface-ECG monitoring.

Types and Prevalence of Postablation Rhythm Follow-up Monitoring

Type of monitoring Prevalence (%)
Clinic visit for ECG 76.6
Holter monitoring 52.9
Implantable monitoring systems 4.5
ECG plus Holter, implanted system, or transtelephonic monitoring 37.8
No monitoring 18.3

Dr Robert Hatala (Slovakia National Cardiovascular Institute and Slovak Medical University, Bratislava), who wasn't involved in the registry but was invited by the ESC to field news reporters' questions about it, agreed that it was a bit surprising that clinicians at the participating centers "weren't very strict" about follow-up monitoring. "They didn't monitor with all the tools we have available," he told heartwire . In particular, he questioned the usefulness of occasionally performed surface ECG. He said he "would have problems" taking patients off anticoagulants if they only had, say, five conventional ECGs over one year, "for altogether maybe one minute of monitoring."

About 65% of patients were on anticoagulation therapy during the follow-up, primarily on vitamin-K antagonists.

"That many of the patients after one year were still on anticoagulants and antiarrhythmic drugs simply reflects a lack of supportive evidence, especially for anticoagulants, to take them off [the drugs]," Hatala said. Without the follow-up monitoring data, clinicians opt for caution and maintain anticoagulant therapy.

"On the other hand," Hatala said, going off anticoagulants "might be motivation for the patient to undergo the procedure in the first place, especially if they are relatively active and their only problem is paroxysmal atrial fibrillation."

Proportion (%) of AF Ablation Patients on Anticoagulant Therapy at 12 Months by Two Scoring Systems for Cardioembolic Risk*

Score CHADS2 CHA2DS2-VASc
0 53.1 48.0
1 69.0 63.3
>1 81.6 76.2

*For both scoring systems, higher scores correspond to greater risk

Another twist in anticoagulant use: accounting for cardioembolic risk--as determined by CHADS2 and CHA2DS2VASc scores--showed a partial disconnect between use of the drugs and apparent need for anticoagulant protection. About half the patients at very low embolic risk were still taking anticoagulants at 12 months, and 20% to 25% patients at high cardioembolic risk weren't on anticoagulants, Arbelo observed.

Anticoagulation management would sharpen considerably if the patients were more consistently followed with "some of our more sophisticated methods to see whether the patient is really arrhythmia-free. Then we would also have much better support for taking the patient off anticoagulation," Hatala said. "The penetration of these tools is suboptimal."

While the surface ECG falls short for the job, implantable loop recorders are "fantastic" for monitoring patients after AF ablation. "At this stage of development of this therapy, it would be very helpful to have more data from implantable loop recorders. Then we could really say a patient is arrhythmia-free, and I would have no problems getting them off anticoagulation."

Medication Use During 12-Month Follow-up After AF Ablation

Medication Baseline (%) Before 12 months (%) After 12 months (%)
Vitamin-K antagonists 87 63 54
Low-molecular-weight heparin 10 2 1
Antiplatelets 55 24 28
Amiodarone 23 16 12
Flecainide 22 16 14

 

Arbelo and Hatala had no disclosures. Leclercq discloses receiving research grants from Boston Scientific, Medtronic, Sorin, and St Jude Medical; consulting or serving on an advisory board for Boston Scientific, Biotronik, Medtronic, St Jude Medical, and Sorin; and lecturing for Boston Scientific, Biotronik, Medtronic, St Jude Medical, Sorin, General Electric, and Boehringer Ingelheim.

Comments

3090D553-9492-4563-8681-AD288FA52ACE
Comments on Medscape are moderated and should be professional in tone and on topic. You must declare any conflicts of interest related to your comments and responses. Please see our Commenting Guide for further information. We reserve the right to remove posts at our sole discretion.
Post as:

processing....