Myocardial Fibrosis and Ventricular Remodeling in Severe Chronic Aortic Regurgitation

Background: Significant symptomatic chronic aortic regurgitation (AR) leads to considerable left ventricular remodeling at the expense of myocyte hypertrophy and extracellular matrix remodeling. The relevance of interstitial fibrosis concentration in these patients is unknown. We analyzed the degree of fibrosis in the left ventricle (LV) in symptomatic patients with AR submitted to surgical treatment, and its relationship with functional and anatomical characteristics. Objective: To evaluate myocardical fibrosis in chronic severe aortic regurgitation. Methods: Twenty-eight patients with chronic symptomatic AR (6 with normal LV function and 2 with LV dysfunction) were selected and assessed pre- and postoperatively by echocardiography. Functional capacity was measured using maximal oxygen consumption (VO(2)max) through the cardiopulmonary test. Myocardial fibrosis volume fraction (MFV) was quantified through endomyocardial biopsy performed in all patients during surgery. We compared the histopathologic results with a nine-patient control group. Results: The mean age was 39 +/- 12 years, 75% of the patients were male, and the rheumatic etiology accounted for 84% of the cases. Twenty-five patients remained in FC I and II at the end of the study, and there was a significant reduction of the LV diameters between the preoperative and late postoperative timepoints. Three deaths occurred but they were not related to postoperative ventricular dysfunction. The parameters of the cardiopulmonary test were similar between pre- and postoperative timepoints. MFV in patients with AR was significantly higher than in the control group (3.47 +/- 1.9% vs 0.82 +/- 0.96%, respectively, p = 0.001). There was no statistical correlation among LV fibrosis and LV diameters, LVEF and MVO(2). Conclusion: In patients with significant symptomatic AR, the presence of limited myocardial fibrosis was not associated with clinical, echocardiographic or functional complications. (Arq Bras Cardiol 2009;92(1):6-64)