P.082 Differential Associations of Left Atrium Volume with BNP and Aortic Stiffness in the Early Stages of Essential Hypertension: Importance of Mechanical and Humoral Components

Abstract

Purpose

To investigate the possible interrelationship between Left atrial (LA) enlargement, BNP and aortic stiffness in essential hypertensive subjects.

Methods

235 consecutive, newly diagnosed subjects (aged 52±10 years), with untreated essential hypertension [office BP = 151/97 mmHg] underwent echocardiography and 24-h ambulatory BP monitoring. LA volume was indexed for body surface area to estimate LA volume index (LAVI). Aortic stiffness was evaluated on the basis of the carotid-femoral pulse wave velocity (c-f PWV) measurement by an automatic device (Complior SP). The study population was divided into two groups: those with increased LAVI (>26ml/m², n = 45) and those without increased LAVI (⩽26ml/m²,n = 181).

Results

Subjects with increased LAVI compared to those without increased LAVI did not differ regarding age, body mass index, 24-h systolic and diastolic BP and metabolic profile. Subjects with increased LAVI compared to those without increased LAVI had significantly increased 24-h pulse pressure (54.6±9.0 vs 51.3±7.9 mmHg, p < 0.05), left ventricular mass index (LVMI) (123±31 vs 99±23g/m², p < 0.0001), LA diameter (4.3±0.38 vs 3.9±0.34 cm, p < 0.0001) and BNP plasma levels (41.5±14 vs 19.7±10 pg/ml, p < 0.05), while did not differ regarding c-f PWV (8.2±1.3 vs 8.1±1.3 m/s, p = NS). Multiple regression analysis model revealed that LVMI and BNP were independent predictors of LAVI (p < 0.05).

Conclusions

Even in newly diagnosed essential hypertensive subjects LA enlargement is associated with increased plasma levels of BNP but not more impaired aortic stiffness. These findings support the notion that LA enlargement is closely related with humoral activation in this setting.