Influence Of Blood Pressure Variability On Left Cardiac Structure And Function In White Coat Hypertension

Objective:To evaluate left cardiac structure and function and analyse the trait of blood pressure variability (BPV) in white coat hypertension, in order to assess the relationship between BPV and left cardiac structure and function.Methods:70 subjects with white coat hypertension and 30 normal controls underwent conventional echocardiography for measurement of Left ventricular internal dimension of diastole (LVIDd), Interventricular septum thickness (IVST), left ventricular posterior wall thickness (LVPWT), left ventricular mass index(LVMI), left ventricular ejection fraction(LVEF), early and late diastolic mitral valve blood flow peak velocity ratio (E / A), left atrial volume index (LAVI). Early diastolic mitral annular velocity(Em,),Late diastolic mitral annular velocity (Am) and systolic peak velocity of mitral annulus myocardium(Sm) were tested by using pulsed-wave Doppler Tissue Imaging (PW-TDI), Em/Am was calculated then.30 normal control subjects were recruited in the study. Echocardiographic parameters were compared between the groups above so as to analyse the correlation between blood pressure variability and echocardiographic parameters.Results:1. Comparison of ambulatory blood pressure between the groups:daytime mean systolic blood pressure,24-hour mean systolic and diastolic blood pressure were significantly greater in WCH group than those in the control group (P<0.05).2. Comparison of blood pressure variability between the groups: 24-hours and daytime blood pressure variability in the WCH group were significantly higher than those in the control group (P<0.05).3. Comparison of echocardiographic parameters between the groups: There were significant difference between the groups in terms of left atrial volume index, left ventricular mass index, Em/Am (P<0.05); There were no significant difference between the groups in terms of Sm, LVEF (p>0.05).4. Correlation analysis:daytime average systolic blood pressure, 24-hour average systolic blood pressure, nighttime average systolic blood pressure, age, gender, body mass index, daytime systolic blood pressure variability and 24-hour systolic blood pressure variability were positively related to left ventricular mass index (P<0.05); Age, heart rate, body mass index, daytime systolic and diastolic blood pressure variability, 24-hour systolic, diastolic blood pressure variability,E/A, Em/Am and left ventricular mass index were positively related to left atrial volume index (P <0.05). Age, heart rate, body mass index, daytime,24-hour and nighttime diastolic blood pressure,daytime and 24-hour blood pressure variability and left ventricular mass index were negatively related to Em/Am(P<0.05).5.With the Em/Am as dependent variables in the multiple stepwise regression analysis showed that 24-hour systolic blood pressure variability, LVMI, heart rate, body mass index,age in white coat hypertension are main factors of affecting Em/Am. Standardizatione-quation:Em/Am=-0.019X24hSBPV-0.011Xheartrate-0.020Xage-0.016XLVMI-0.03 4XBMI+4.759 (P＜0.05)6. The multiple stepwise regression analysis, in which the left atrial volume index was regarded as dependent variable, showed that 24-hour systolic blood pressure variability, LVMI, heart rate, body mass index and Em/Am are main affecting factors of increasing LAVI in white coat hypertension. The standardization equation:LAVI= 0.675X24hSBPV-3.376 XEm Am+0.171 Xheartrate+0.083XLVMI-0.474XBMI+10.188 (P<0.05).7. The multiple stepwise regression analysis, in which the left ventricular mass index as regarded as dependent variable, showed that 24-hour average systolic blood pressure, age and gender are the main affecting factors of increasing LVMI in white coat hypertension. The standardization equation:LVMI=0.374X24hSBP+ 14.203Xsex+0.723Xage-19.675 (P<0.05)Conclusion:1.Left atrial volume index, left ventricular mass index in white coat hypertension are higher than normal controls.2. In white coat hypertension, left ventricular diastolic function decreased, but left ventricular systolic function remains normal.3. Blood pressure variability in white coat hypertension is higher than normal controls.4. Blood pressure variability is an important affecting factor in left cardiac structure and function in white coat hypertension...