Effects of endocardial MAZE procedure on dynamics of extracellular matrix proteolysis and growth factor concentrations in patients with atrial fibrillation

Aim. The aim of the study was to determine the effects of interventional treatment for atrial fibrillation (AF) on the dynamic changes in the system of extracellular matrix proteolysis. Material and methods. A total of 50 patients were included in the study: 27 patients (18 males) had persistent AF (mean age of 62.1±9.4 years); 23 patients (14 males) had long-lasting persistent AF (mean age of 64±11 years). All patients received radiofrequency antral pulmonary veins isolation and linear lesions on the back wall of the left atrium and the mitral isthmus with CARTO system (Biosense Webster, USA). Blood serum changes in the parameters of extracellular matrix proteolysis and concentrations of growth factors including matrix metalloproteinase (MMP)-1, MMP-3, MMP-9, tissue growth factor β1 (TGF-β1), tissue inhibitor of matrix metalloproteinases 1 (TIMP-1), and fibroblast growth factor (FGF) were determined before the Maze procedure, immediately after the procedure, after 1 day, 3 months, and 6 months. Results. The concentrations of all MMPs immediately after the Maze procedure dramatically decreased most likely due to significant thermal damage of the left atrium. On the next day after the procedure, the MMP-1 concentration restored to the initial level, the MMP-3 concentration remained at the same level, whereas the MMP-9 concentration drastically increased to the level exceeding the initial value. After 3 months, the concentrations of MMP-1 and MMP-3 were near the initial levels, whereas MMP-9 concentration dropped to the level recorded immediately after the procedure. After 6 months of observation, the MMP-1 concentration demonstrated downward trend and was lower than the initial value; the MMP-1 level also did not reach the initial level; and the MMP-9 concentration returned to the initial level. The TGF-β1 concentration also dramatically dropped right after the procedure and slowly recovered during 6 months of follow-up. The decrease in the TGF-β1 concentration immediately after the procedure can be explained by massive cell death in the atrial myocardium. One day after the procedure, the TGF-β1 concentration increased and reached the initial level, but it decreased after 3 and 6 months. Conclusion. The reductions in the concentrations of MMPs and growth factors in the absence of AF after the Maze procedure resulted from the arrest and perhaps the reversal of the structural remodeling.