Objectives: The Cox maze procedure was developed as a surgical treatment for atrial fibrillation. However, atrial fibrillation recurs in some patients, and atrial remodeling in the form of fibrosis can lead to perpetuation of atrial fibrillation. To identify the predictor of the persistence of atrial fibrillation after the maze procedure using cryoablation, we evaluated the preoperative plasma transforming growth factor beta1. We also examined the correlations between plasma transforming growth factor beta1 levels and the degree of atrial fibrosis.
Methods: Preoperative plasma transforming growth factor beta1 levels were measured in 86 consecutive patients (age, 54 +/- 12 years) who underwent both the open heart operation for valvular heart disease and the surgical maze procedure with cryoablation for persistent atrial fibrillation. We measured the degree of fibrosis from the tissue of the left atrium.
Results: At 1 year's follow-up, 10 of 86 patients had persistent atrial fibrillation. Patients with persistent atrial fibrillation had higher preoperative plasma transforming growth factor beta1 levels than the patients with sinus rhythm (0.44 +/- 0.29 vs 0.32 +/- 0.15 ng/mL, P = .03). Patients with persistent atrial fibrillation had higher mRNA expressions of collagen III and lower mRNA expressions of atrial natriuretic peptide than those with sinus rhythm, and the plasma transforming growth factor beta1 levels correlated with the degree of fibrosis in the left atrium (r = 0.497, P = .022). Multiple logistic regression analysis revealed that plasma transforming growth factor beta1 levels were independently associated with the postoperative persistence of atrial fibrillation at 1 year's follow-up.
Conclusions: Preoperative plasma transforming growth factor beta1 levels could be used to predict the persistence of atrial fibrillation at 1 year's follow-up after the surgical maze procedure by using cryoablation. Preoperative plasma transforming growth factor beta1 levels were correlated with the degree of fibrosis in the left atria of patients with mitral valvular heart disease.