The Impact Of Metabolic Syndrome On Left Heart Structure And Function In Patients With Essential Hypertension

Objective Epidemiological studies show that patients with metabolic syndrome have more risk of cardiovascular events. To elucidate the mechanisms, this study was designed to evaluate the impact of metabolic syndrome on left heart structure and function in patients with essential hypertension.Methodology/Principal Findings This study was conducted on a hospitalbased case-control. Metabolic syndrome(MS) was defined according to guidelines from the Ministry of Health of China in 2007. Based on the diagnostic criteria of metabolic syndrome, patients were divided into three groups: essential hypertension and MS group(HTMS group, n=197), essential hypertension without MS group(HNMS group, n=163), control group(ND group, n=96) without any one of five risk factors about the diagnostic criteria of MS. Data were analyzed by SPSS 23.0 software. The incidence of left ventricular systolic function, left ventricular hypertrophy and left atrial enlargement among the three groups were compared by chi-square test, and the way of multiple comparisons were Bonferroni correction. Pearson correlation analysis was used to identify relevant factors of LVMI and LOA. Logistic regression analysis was used to assess the risk factors of left ventricular hypertrophy(LVH) and left atrial enlargement(LAE).Results(1) The level of blood pressure(BP, mm Hg) in HTMS group and HNMS group were higher than in ND group(P<0.05), no significant difference was found between HTMS group and HNMS group(P>0.05).(2)Left ventricular mass(LVM, g), left ventricular mass index(LVMI, g/m2.7) and left atrial diameter(LAD, mm) in HTMS group and HNMS group were higher than in ND group, and HTMS group was significantly higher than HNMS group(LVM: 183.64±49.48 > 159.12±51.98 >133.02±51.06; LVMI: 47.74±10.90 > 42.35±11.97 > 35.23±11.87; LAD: 40.10±5.74 > 36.91±5.69 > 33.29±5.60; P <0.05).(3) The incidence of left ventricular hypertrophy among the three groups in descending sort followed : HTMS group(33.5%)> HNMS(19.0%)> ND group(6.6%)(P <0.01).(4) Changes of cardiac structure were further subdivided into four categories: normal, left ventricular concentric hypertrophy, left ventricular concentric remodeling and left ventricular eccentric hypertrophy. Our further analysis found that there were no difference in the incidence of left ventricular concentric hypertrophy among three groups(P >0.05). There were significant difference in the incidence of left ventricular concentric remodeling among three groups(P <0.05), the incidence of concentric remodeling were rising from ND group, HNMS group to HTMS group(1.9%, 6.1%, 11.7%). There were significantly difference in the incidence of left ventricular eccentric hypertrophy among three groups(P <0.05). The incidence of left ventricular eccentric hypertrophy in HTMS group was significantly higher than in HNMS group and ND group, and in HNMS group higher than in ND group(26.4% > 13.5% > 3.8%, P <0.01).(5) There was no significant difference among the three group on left ventricular systolic function(ND group 2.1%, HNMS group 3.1%, HTMS group 4.1%, P>0.05). Left ventricular diastolic function were significantly different among the three groups, e, e1, E/A: ND group > HNMS group > HTMS group(P<0.05); E/e': HTMS group > HNMS group > ND group(P<0.05).(6)The incidence of LAE in HTMS group was significantly higher than in HNMS group and ND group, and in HNMS group higher than in ND group(71.1% > 47.9% > 20.8%, P <0.01).(7)Analysis results of Pearson correlation : LVMI with age, SBP, DBP, PP, history length of hypertension, BMI, waist circumference, fasting plasma glucose, TG, Cr, BUN, UA were positively correlated(P <0.05), and the maximum value of correlation coefficient was BMI(r = 0.400); LVMI with HDL-C, Apo A1, magnesium were negatively correlated(P <0.05), and the maximum absolute value of correlation of magnesium was HDL-C(r =-0.243). LOA with age, SBP, DBP, PP, history length of hypertension, BMI, waist circumference, fasting plasma glucose, TG, Cr, UA, BUN, Cr, fibrinogen were positively correlated(P <0.05), and the maximum value of correlation coefficient was waist circumference(r = 0.466); LOA with HDL-C, Apo A1 was negatively correlated(P <0.05), and the absolute value of correlation of HDL-C(r =-0.240) was greater.(8) Analysis results of logistic regression: 1) The risk factors of LVH were including obesity(OR : 1.799, 95% CI: 1.070 ~ 3.022), UA(OR: 1.707, 95% CI: 1.049 ~ 2.776). 2) The risk factors of LAE were including Age(OR: 1.894, 95% CI: 1.240 ~ 2.893), BP(OR: 2.302, 95% CI: 1.185 ~ 4.475), obesity(OR: 2.152, 95% CI: 1.335 ~ 3.469). However, there were greater risk of LAE in men than in women.Conclusions MS is correlated with LVH in patients with essential hypertension, especially with left ventricular eccentric hypertrophy. MS is correlated with LAE in patients with essential hypertension, and men are correlated with LAE. Obesity is an independent risk factor of LVH and LAE. UA is an independent risk factor of LVH.