The use of prophylactic pulmonary vein isolation (PVI) in patients with typical atrial flutter significantly reduced new onset of atrial fibrillation and burden, the associated number of hospitalizations and repeat ablation for AF, according to three-year results of the PREVENT AFI study presented Tuesday at Scientific Sessions.
These results confirmed the benefit of PVI seen after one-year follow-up in the study. Patients were assessed using continuous implantable loop recorder with a battery life of about three years that allowed Jonathan Steinberg, MD, and colleagues to continue to follow outcomes for an extended period.
“Over three years, there was still a substantial reduction in the incidence of atrial fibrillation,” said Steinberg, a cardiologist with the University of Rochester in New York. “Because we documented this with the implantable loop recorder, we saw a substantial reduction of about two-thirds of atrial fibrillation burden over time. Prophylactic ablation worked in greatly reducing the amount of new onset atrial fibrillation.”
The study included 50 patients with documented atrial flutter randomly assigned to either cavo-tricuspid isthmus (CTI) ablation alone (n=25) or CTI with concomitant PVI (n=25). All patients received an implantable loop recorder and had regular follow-up for three years. The primary endpoint of the study was the occurrence of any atrial tachyarrhythmia including AF or atrial flutter after ablation with the monthly burden exceeding 0.5 percent on the recorder.
At three years, 80 percent of patients who did not have prophylactic PVI developed AF or atrial flutter compared with only about half (52 percent) of patients in the CTI plus PVI group (hazard ratio=2.40; 95 percent CI, 1.18-4.86; P=.015).
Because the researchers were able to follow patients for this extended period they could clinically track other outcome events, Steinberg said.
“We found that one-third of patients who did not have prophylactic ablation were referred back for ablation for atrial fibrillation,” he said. “We also found that patients who did not undergo prophylactic ablation had a much higher likelihood of visiting the hospital or emergency room, or being hospitalized for cardiovascular causes, which we suspect were largely atrial fibrillation.”
Specifically, 32 percent of patients in the CTI alone group underwent repeat ablation compared with 8 percent in the PVI plus CTI group (P=.037). The three-year AF burden was only 6.2 percent for prophylactic PVI compared with 16.8 percent for the CTI alone group (P=.038). Finally, about half (48 percent) of patients in the CTI alone group were hospitalized during the follow-up period compared with 16 percent of patients who underwent prophylactic ablation (P=.032).
“We may be moving in a different direction now when it comes to applying prophylactic ablation for AF,” Steinberg said. “In future research, we may be looking at groups that have high risk of AF who may be candidates for additional clinical investigation or for prophylactic ablation procedures.”