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Effects of βreceptor Blocker on Intraventricular Pressure Gradient after Aortic Valve Replacement

Abstract： Objective To investigate the effects of βreceptor blocker on intraventricular pressure gradient and left ventricle remodeling after valve replacement for critical aortic stenosis. Methods Fifty-six patients with critical aortic stenosis underwent aortic valve replacement surgery from January 2008 to January 2010 in the First Affiliated Hospital of Zhengzhou University. Thirtytwo of them who were followed up were selected to be enrolled in this study. The patients were divided into two groups under the same basis of clinical features. Twelve patients in the experimental group received oral βreceptor blocker (Metoprolol, 6.2525.00 mg once, twice daily). The rest 20 patients in the control group had no βreceptor blocker. The various indicators of ultrasound cardiogram (UCG) shortly after operation (within a week) and long after operation (6-24 months) were compared between the two groups. Results No death occurred in both groups, and chest distress, shortness of breath and other symptoms were obviously alleviated. Although left ventricular endsystolic dimension (LVESD) and left ventricular outflow tract dimension (LVOTD) of both groups increased 6-24 months after operation, compared with the early postoperative period, only the increase of LVOTD in the experimental group showed statistical difference (t=-47.937, P=0.001). In both groups, interventricular septum thickness (IVST), left ventricular posterior wall thickness (LVPWT), filament band velocity of left ventricular outflow tract (V), intraventricular pressure gradient (G) and left ventricular mass index (LVMI) of the later period after operation were significantly lower than those of the early postoperative period. All these indicators in the experimental group showed significant differences (t=7.781, P=0.001；t=5.749, P=0.001; t=2.637, P=0.023; t=7.167, P=0.001; t=100.061, P0.001), while only V, G， and LVMI showed statistical differences in the control group (t=4.051, P=0.001; t= 4.759, P= 0.001; t=-0.166,P=0.001). EF in the experimental group also indicated significant difference compared with early period after aortic valve replacement (t=-6.621, P=0.001). EF between two groups indicated no significant difference (t=-0.354,P=0.726). But differences between the two groups in LVEDD, IVS, G， and LVMI were all statistically significant in the later period after surgery (t=-2.494, P=0.018; t=-3.434, P=0.002;t=-2.171,P=0.038; t=-2.316, P=0.028). Conclusion β-receptor blocker is a safe and reliable drug for those patients who have undergone aortic valve replacement surgery for critical aortic stenosis, and can decrease significantly the residual intraventricular pressure gradient and accelerate left ventricular cardiac remodeling. 