ANAHEIM, Calif. — Epicardial fat pad injections of botulinum toxin may be a safe way to reduce postoperative atrial fibrillation without increasing adverse events after cardiac surgery, according to the results of the TNT-POAF study presented at the American Heart Association Scientific Sessions.
“Postoperative AF is the most common complication after cardiac surgery and is unfortunately one that is associated with postoperative morbidity, increased length of stay in the ICU in the hospital and short and long-term mortality,” Nathan H. Waldron, MD, MHSc, from Duke University Medical Center, said during his presentation. “Cardiac autonomic dysregulation has consistently been linked with the development of AF and the clinical strategies to modulate the intrinsic cardiac autonomous nervous system met some preliminary success in reducing AF.”
With this preliminary success in mind, Waldron and colleagues conducted a double-blind randomized controlled trial to evaluate the efficacy and safety of epicardial botulinum toxin injection to reduce postoperative AF.
Botulinum toxin is also used for facial injections and to treat muscle stiffness/spasms and migraines.
According to Waldron, patients undergoing CABG, valve surgery or CABG plus valve surgery underwent 1:1 randomization to either injection of botulinum toxin or normal saline in five epicardial fat pads. Providers and research staff were also blinded to treatment assignment.
The primary outcomes were time to onset of first postoperative AF episode, both unadjusted and adjusted for various risk factors to account for baseline differences between the groups.
Key secondary outcomes were the occurrence of postoperative AF, burden of in-hospital postoperative AF, ICU, length of hospital stay and postoperative adverse events
Time to onset of first postoperative AF episode did not differ between groups, either in unadjusted (HR = 0.69; 95% CI, 0.4-1.18) or adjusted (HR = 0.7; 95% CI, 0.41-1.21) analyses, Waldron said.
Duration of first episode was shorter in those assigned botulinum toxin (1.9 hours vs. 5.5 hours; P = .01), but there was no difference in the other key secondary outcomes, according to the researchers.
While there was no significant difference in the incidence of postoperative AF between groups, Waldon said it was 11% lower in patients receiving epicardial botulinum toxin.
Limitations include the enrollment of high-risk, heterogeneous cardiac surgical patients at a single academic institution and the inability to detect smaller, but potentially clinically significant reductions in the risk of post-operative AF, he said.
“Epicardial botulinum toxin may be a safe way to reduce postoperative AF, but warrants further study in larger scale clinical trials,” Waldon concluded. – by Dave Quaile
Waldon N. LBS.07. Innovative Therapies and Novel Applications. Presented at: American Heart Association Scientific Sessions; Nov. 11-15, 2017; Anaheim, California.
Waldron reports no relevant financial disclosures.