Mortality Risk One in 1000 for Patients Undergoing Catheter Ablation of AF

May 06, 2009

May 6, 2009 (Milan, Italy) — Roughly one patient in 1000 will die from complications caused by the catheter ablation of atrial fibrillation (AF), with the most common cause of death being tamponade, followed by stroke and atrioesophageal fistula [1].

These are the findings of a large retrospective analysis of 45 000 ablation procedures in 32 000 patients performed worldwide between 1995 and 2006. Investigators report that center experience did not appear to influence the risk of death, nor did different ablation techniques.

"The present study provides an unprecedented view of the causes and incidence of death in patients undergoing catheter ablation of AF, which may be of help in designing more appropriate and efficient [electrophysiology] EP settings for increasing current standards of procedural safety, planning start programs in EP centers with limited facilities or experience, delivering recommendations by regulatory authorities, and developing safer technologies," write Dr Riccardo Cappato (Policlinico San Donato, Milan, Italy) and colleagues in the May 12, 2009 issue of the Journal of the American College of Cardiology.

In an editorial accompanying the published report [2], Dr Bernard Belhassen (Tel-Aviv Sourasky Medical Center, Israel) asks whether a mortality rate of approximately one in 1000 can be considered an "acceptable risk" for patients with AF, particularly since the main expectation from the procedure is an improvement in the quality of life. Until recently, clinicians had little they could tell their patients about the procedure, except to say that it was associated with a relatively low complication rate, he notes.

"Now, after the publication of this report, they will be aware of the one-per-1000 mortality rate," writes Belhassen. "It is possible that some of them will prefer alternative options to manage their arrhythmias, such as another antiarrhythmic drug trial, a rate-control policy, or even a visit to their local emergency room."

Mortality Rate of 0.98 Per 1000 Patients

In 2005, Cappato and colleagues published a survey on the methods, efficacy, and safety of catheter ablation of AF, reporting at least one major complication in 6% of patients who underwent the procedure between 1995 and 2002. The latest safety analysis combines results from the first survey with more recent data on patients who underwent ablation between 2003 and 2006. Surveys were sent to EP centers around the world, with 162 completing questionnaires reporting the number of early and late deaths in patients undergoing catheter ablation for AF.

In total, 32 deaths were reported from 45 115 procedures in 32 569 patients with AF. This translates into a mortality rate of 0.98 per 1000 patients. There were 25 deaths within the first 30 days, tamponade being the most frequent cause, followed by five reported cases of atrioesophageal fistula.

Causes of Death in 32,569 Patients From 162 Centers

Causes of death n (%)
Early death (within 30 d)  
Tamponade 7 (21.8)
Atrioesophageal fistula 5 (15.6)
Stroke 3 (9.4)
Massive pneumonia 2 (6.3)
1 event each of MI, pulmonary vein perforation, irreversible torsades de pointes, septicemia, sudden respiratory arrest, acute pulmonary vein occlusion, hemothorax, and anaphylaxis 1 (3.1)
Late death (after 30 d)  
Stroke 2 (6.3)
1 event each of tracheal compression of subclavian hematoma, acute respiratory distress syndrome, esophageal perforation from TEE probe, tamponade with subsequent cardiac arrest in prior stroke, and intracranial bleeding under anticoagulation therapy in prior stroke 1 (3.1)
TEE=transesophageal echocardiography

Investigators report that death rates did not vary with volume: death rates were similar among centers that performed less than 100 ablations annually, those that performed between 100 and 250 annually, and those that did more than 250 cases per year. Similarly, there was no difference in death rates among patients undergoing catheter ablation of atrial flutter guided by electroanatomic mapping (CARTO) vs those undergoing lasso-guided ablation.

There was a statistically nonsignificant higher risk of death associated with the use of irrigated or cooled-tip ablation catheters compared with the use of a 4-mm-tip catheter, and investigators urge careful prospective monitoring to "exclude a greater degree of harm with use of more powerful ablation catheters."

Is Surgical Backup Needed?

In his editorial, Belhassen writes that because tamponade is the most frequently observed complication in ablation procedures, it is important that operators have good experience in percutaneous pericardiocentesis or have access to a doctor who does. Where pericardiocentesis fails to drain the fluid from the pericardial sac, surgery can be required, although there are nonsurgical drainage approaches.

"As such, the question of whether AF ablation procedures should only be performed in electrophysiologic centers where surgical backup is available remains unresolved," writes Belhassen. "My personal view is that surgical backup is mandatory and that it may prevent a lethal outcome in some patients."

In terms of some of the limitations, Belhassen points out the retrospective nature of the analysis and that mortality rates tend to be higher in prospective studies. Also, the data do not account for differences in outcomes between men and women.

Cappato is a consultant and speaker for Biosense Webster and St Jude Medical, a consultant for Bard, and on the advisory board for St Jude Medical and has received research grants from Biosense Webster, St Jude Medical, and Bard.

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