OPG/RANK/RANKL Axis in Stabilization of Spontaneously Restored Sinus Rhythm in Permanent Atrial Fibrillation Patients after Mitral Valve Surgery

OBJECTIVE: To investigate the expression of the osteoprotegerin (OPG)/receptor activator of nuclear factor-ĸB (RANK)/RANK ligand (RANKL) axis in the stabilization of spontaneously restored sinus rhythm (SR) in permanent atrial fibrillation (AF) patients after mitral valve (MV) surgery and study its clinical significance. METHODS: Clinical data, biopsies of right atrial appendages were collected from 135 permanent AF patients who spontaneously restored SR after conventional isolated MV replacement. A comparison was made between patients who had recurrence of AF within 7 days and patients with persistent SR for more than 7 days. RESULTS: AF patients had an increased expression of RANK, RANKL, and the RANKL/OPG ratio compared to SR patients, and the degree of fibrosis was lower in SR compared to AF in the atria. Moreover, the expressions of RANK, RANKL, and the RANKL/OPG ratio were positively correlated with the degree of fibrosis. CONCLUSION: These findings suggest that the OPG/RANK/RANKL axis plays important roles in the stabilization of restored SR after MV surgery by stimulating AF-related atrial remodeling in AF patients.