The addition of image-guided atrial fibrosis ablation did not significantly reduce the risk of recurrence relative to pulmonary vein isolation (PVI) alone in patients with treatment-resistant atrial fibrillation (AFib), according to results of an intention-to-treat analysis of the randomized DECAAF II trial.
Mitchel L. Zoler/MDedge News
Dr. Nassir F. Marrouche
However, there was a significant advantage for the addition of image-guided ablation in the subgroup of patients with stage I or II fibrosis, and this is a clinically meaningful finding, Nassir F. Marrouche, MD, reported at the annual congress of the European Society of Cardiology.
“Patients at early stages [of fibrosis] appear to do well if you do a good job covering the myopathy [with scar formation], and that is an important message,” said Dr. Marrouche, the principal investigator.
The underlying hypothesis of the DECAAF trial was that ablation guided with MRI imaging would prove superior to PVI alone in the treatment of resistant AF. There were 843 participants randomized at 44 centers. At baseline, all underwent a late gadolinium-enhancement MRI, a technique that allows detection of fibrotic tissue.
After randomization, those in the control group underwent standard of care PVI alone. Those in the intervention group underwent ablation of areas of the atrium revealed to be fibrotic on the MRI scan in addition to PVI.
Five percent risk reduction not significant
After a median follow-up of 12 months, recurrence of AFib, which was the primary endpoint, was observed in 43% in the intervention group and 46.1% in the control group. The relative 5% reduction for treatment was not statistically significant (hazard ratio, 0.95; 95% confidence interval, 0.778-1.17; P = .63).
As part of the study protocol, MRI was repeated 3 months after treatment in all patients. This permitted the investigators to evaluate the degree of scar formation in relation to the fibrosis covered in the intervention group. Independent reviewers rated this coverage on levels from 1 to 5, with 5 representing complete coverage.
In this analysis, it was found that ablation resulted in higher levels of lesion formation in those with early stages of disease, defined as stage I or II fibrosis, but lower levels in advanced stages.
“The more myopathy, the more disease, the less likelihood of lesion formation,” reported Dr. Marrouche, professor of medicine in the section of cardiology at Tulane University, New Orleans.
Attributed to the greater levels of fibrosis coverage, the risk of AF recurrence over the course of follow-up was significantly reduced in the intervention relative to the control group on as-treated analysis in patients who had stage I or II fibrosis at baseline. (HR 0.841, 95% CI, 0.732-0.968; P < .05).