Dilatation of the ascending aorta and serum alpha 1-antitrypsin level in patients with bicuspid aortic valve

Abstract

Predictors of aortic dilatation are not well described in patients with bicuspid aortic valves (BAV). This study sought to examine the relationship between proximal aortic dilatation and matrix metalloproteinase-9 (MMP-9) and alpha 1-antitrypsin (alpha 1AT) levels in patients with BAV. All patients underwent echocardiography using a standard protocol, and aortic measurements were taken in end-diastole. We studied 82 patients with BAV and categorized them into two groups according to aortic dimensions corrected for body surface area and age. The plasma level of alpha 1AT was routinely determined using a BN ProSpec analyzer (Siemens Healthcare Diagnostics, Marburg, Germany), and that of MMP-9 were determined by ELISA (RayBiotech Inc. Norcross, GA, USA). Statistical analysis was performed using the Statistical Package for Social Sciences (SPSS; SPSS Inc., Chicago, IL, USA) software for Windows version 12. This study included patients with BAV with no or mild valvular impairment. There were no significant differences between groups in terms of gender, body surface area, associated hypertension, diabetes mellitus, hyperlipidemia, or smoking. The mean ascending aortic diameter was 4.38 +/- A 0.5 mm in group 1 and 3.34 +/- A 0.35 mm in group 2 (p < 0.001). Plasma concentration of alpha 1AT in patients with ascending aortic dilatation was significantly lower than that in the non-dilated group (1.32 +/- A 0.27 and 1.49 +/- A 0.25 g/l, respectively; p = 0.005). However, no significant difference was found in the MMP-9 level between the two groups (336.49 +/- A 233.11 and 336.39 +/- A 268.072 pg/ml, respectively; p = 0.96). We observed a significantly negative correlation between ascending aortic diameter and alpha 1AT level (r = -0.300, p = 0.006) and a positive correlation between ascending aortic diameter and age (r = 0.413, p < 0.001). No significant correlation was found between plasma MMP-9 concentration and ascending aortic diameter (r = -0.008, p = 0.94). A multiple linear regression analysis was performed, including age, alpha 1AT level, MMP-9 level, and left ventricular diastolic diameter. In this analysis, alpha 1AT level and age were the independent predictors of aortic dilatation (p = 0.03 and p = 0.02, respectively).