BACKGROUND Atrial remodeling leads to perpetuation of atrial fibrillation (AF). Structural remodeling in the form of fibrosis alters the substrate. The surgical Maze procedure was developed as a surgical treatment of AF. Our purpose was to evaluate the role of plasma TGF-b1, MMP-3 (Matrix MetalloProteinase-3), and pro-MMP-1, TIMP-1 (Tissue inhibitors of MetalloProteinase-1), NT-proBNP, hsCRP in predicting the recurrence of AF after surgical Maze procedure. And we also evaluated the association of expression of TGF-b1, CTGF (Connective Tissue Growth Factor), BNP, ANP, collagen-I, and collagen-III in LA with the recurrence of AF after surgical Maze procedure.
METHODS Preoperative plasma NT-proBNP, hsCRP, TIMP, TGF-b1, MMP-3, and pro-MMP-1 levels were measured in consecutive 86 patients (age 54±12 yrs) who underwent the open heart operation for valvular heart disease and surgical Maze procedure for AF. Moreover, we performed molecular examinations of CTGF, TGF-b1, BNP, ANP, Collagen-Ia, Collagen-IIIa in the resected left atrial tissues. Symptomatic AF documented by ECG or an episode of AF revealed at follow-up holter monitoring were considered atrial fibrillation recurrences.
RESULTS At 1-year follow-up, 10 among 86 patients had persistence of AF. Patients with AF persistence had higher plasma TGF-b1 levels than the patients with sinus rhythm (0.44 ± 0.29 vs 0.32 ± 0.15 ng/ml). Patients with AF persistence had higher messenger RNA expressions of Collagen-IIIa (0.21 ± 0.20 vs 0.12 ± 0.12, compared with internal standard GAPDH by RT-PCR) and lower messenger RNA expressions of ANP (0.31 ± 0.16 vs 0.60 ± 0.76, compared with internal standard GAPDH by RT-PCR) in left atrial tissues. Multiple logistic regression analysis revealed that plasma TGF-b was independently associated with postoperative persistence of atrial fibrillation at 1-year follow-up after surgical Maze procedure.
CONCLUSIONS Advanced atrial degenerative change might result in a decrease of atrial ANP secretion. Cardiac fibrosis might be a determinant of myocardial heterogeneity and the persistence of AF. Plasma TGF-b1 could predict the persistence of AF at 1-year follow-up after surgical Maze procedure.
|
