The use of catheter ablation to treat atrial fibrillation (AF) has expanded in recent years. But the complicated technique makes patient selection, operator experience and setting all the more critical to achieve a successful procedure and good outcomes.
One in four 40-year-old Americans faces a lifetime risk of developing AF, which is a risk factor for stroke (Circulation 2011;123:e18-e209). Antiarrhythmic drugs are considered first-line treatments, but if they fail, some electrophysiologists turn to catheter ablation. An analysis of National Hospital Discharge Survey data found that ablation utilization increased 15 percent annually between 1990 and 2005 across all age groups (J Hosp Med 2009;4: E1-E5). But the procedure is not without risks; in an international survey, Hugh G. Calkins, MD, director of the arrhythmia service and electrophysiology (EP) lab at Johns Hopkins Hospital in Baltimore, and colleagues found major complications in 4.5 percent of cases (Circ Arrhythm Electrophysiol 2010;3;32-38).
Calkins, co-author of a 2012 international consensus statement on AF catheter ablation, says that the field has made strides in recent years, but gaps remain. The statement, written jointly by the Heart Rhythm Society and its European counterparts, focuses on optimal approaches for performing AF ablation and reporting outcomes and provides a state-of-the-art review of clinical evidence.
Sana M. Al-Khatib, MD, MPH, director of clinical EP research at Duke University Medical Center in Durham, N.C., who with colleagues spearheads an effort to build a national registry on AF ablation, says outcomes hinge on many factors. “My expectation is that there is a lot of variation in terms of who is doing the procedure, what patients are undergoing the procedure and the outcomes, both in efficacy and safety,” she says. The SAFARI registry might help define the extent of such variation.
The evidence on AF ablation for patients with persistent AF, long-standing AF and heart failure as “limited,” says Calkins. For these patients, he recommends that physicians clearly rule out medication as an option and educate patients because “the efficacy will be less and the complications will be higher.”
Calkins and Al-Khatib agree that operator experience also plays a role in a successful procedure and good outcomes. The consensus recommendations include a detailed section on possible complications to help mitigate operator-related problems. “When you have someone performing the procedure who is less experienced, it is perhaps not surprising that complications are more common,” says Calkins.
Much of clinical research focuses on a narrow patient population treated at academic hospitals. To better understand inpatient complications and outcomes in other settings, Rashmee U. Shah, MD, a cardiologist at Cedars-Sinai Medical in Los Angeles, et al analyzed data on AF ablation from the California State Inpatient Database (J Am Coll Cardiol 2012;59:143-149). The number of cases jumped from 684 procedures performed at 60 hospitals in 2005 to 1,332 performed at 77 sites in 2008. The year the procedure was done did not predict complications, Shah says, possibly because higher complication rates from inexperienced operators cancelled out declines as others gained experience and expertise.
They also found that inpatient complications occurred at a rate of 5.1 percent each year. Of patients discharged, 9.4 percent were rehospitalized within 30 days, with AF or atrial flutter cited as the most common reason. At one year, the rate of all-cause hospitalization was 38.5 percent and the rate for recurrent AF, atrial flutter and/or repeat ablation was 27.1 percent. Patients who were older, female, had prior AF hospitalization or a recent hospital experience had a higher risk of complications and readmission.
The results highlight areas of concern that should be investigated further, says Shah. A registry may help elucidate these issues but SAFARI lacks funding to move forward. CABANA, a large, multicenter randomized trial intended to study AF ablation compared with medical therapy, offers promise but it is progressing slowly. Many pressing needs appear to be competing for scarce resources.
How to prioritize between a registry and a randomized prospective trial of the elderly or of heart failure patients when all hold value? “That is the question,” Calkins observes.