Hemodynamic changes, atrial remodeling and deposits of atrial natriuretic peptide in patients with atrial fibrillation are associated with clinical outcome of the maze operation

Abstract

Background: Isolated atrial amyloid (IAA) deposition in the left atrium (LA) is associated with atrial fibrillation (AF), and the maintenance of AF results in remodeling of the atrial substrate. However, there is no direct evidence of an association between atrial deposition of atrial natriuretic peptide (ANP) and atrial amyloids in patients with AF, and the clinical implications of this after the maze operation have not been investigated.Methods: Twenty left atrial appendage (LAA) tissues were acquired during mitral valve surgery and the maze operation. All tissues were stained with Congo red under polarized light to detect amyloids, and the area of amyloid deposits was quantified using Image Pro. ANP level was evaluated by Western blotting. And we quantified the protein expression of endocardial functions (endocardial nitric oxide [eNOS], phosphorylated eNOS [Phospho-eNOS]), intercellular adhesion molecule-1 (ICAM-1) and thrombotic factors (von Willebrand factor [vWF], a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13 [ADAMTS13]) by Western blotting. Hemodynamic factors (pulmonary arterial pressure, PAP) were measured prior to the operation were analyzed according to the expression of ANP.Results: 1. ANP+ patients had a lower systolic PAP (p=0.04) than ANP- patients, and the presence of amyloid deposits was also negatively correlated (r=-0.6, p=0.008) with systolic PAP. 2. The expression level of eNOS (p=0.043), phospho-eNOS (p=0.013), vWF (p=0.031) and ICAM-1 (p=0.013) were lower in tissue with ANP expression (ANP+) than ANP- tissues. 3. More amyloid deposits were detected in ANP+ tissue than ANP- tissue (p=0.002). 4. Recurrence of AF after the maze operation was higher in ANP+ patients than ANP- patients (p=0.033), and all recurrence occurred within 150 days. ANP+ status was significantly associated with the recurrence of AF after maze (p=0.005) even after adjusting for age, sex, and LA volume for a mean of 362.3±473.8 days (maximum 1,565 days).Conclusions: Atrial deposits of ANP showed a negative correlation with PAP, and reflected the presence of more atrial amyloid deposits. Deposition of ANP was strongly associated with decreased endocardial function and expression of intercellular adhesion molecule. Finally, expression of ANP was significantly associated with AF recurrence after the maze operation.