Abstract 2469: Circadian Blood Pressure Variation and Left Atrium Size in the Early Stages of Essential Hypertension: The Role of Pulse Pressure and Nocturnal Blood Pressure Fall

Abstract

Introduction: Left atrial (LA) enlargement is a common finding in hypertensive patients and might be an index for future adverse cardiovascular events. Similarly, increased pulse pressure (PP) as well as absence of nocturnal blood pressure (BP) fall is associated with unfavourable outcome in this setting. Hypothesis: Ambulatory BP parameters may be correlated with LA size in essential hypertension. Methods: 332 consecutive, newly diagnosed subjects (aged 52±10 years), with untreated stage I–II essential hypertension [office BP =152/98 mmHg] were classified according to their nocturnal BP fall on 24-hour ambulatory BP monitoring to non-dippers (those with<10% nocturnal systolic and diastolic BP fall, n=194) and dippers (the remaining subjects, n=138). All subjects underwent complete echocardiographic study and LA volume was indexed for body surface area to estimate LA volume index (LAVI). Results: Non-dippers compared to dippers did not differ regarding age, sex, office BP and biochemical profile (p=NS for all cases). However, non-dippers compared to dippers had significantly increased 24-h systolic BP (138±14 vs 135±11 mmHg, p<0.05), 24-h pulse pressure (PP) (53±9 vs 51±8 mmHg, p<0.05) and night PP (53±10 vs 47±8 mmHg, p<0.001) as well as left ventricular mass index (108±28 vs 101±26 gr/m 2 , p<0.05) and relative wall thickness (0.44±0.07 vs 0.42±0.07, p<0.05), while they did not differ regarding LA diameter (3.95±0.39 vs 3.86±0.39 cm, p=NS) and LAVI (24.1±6.3 vs 23.5±6.1 ml/m 2 , p=NS). In the entire population LA diameter and LAVI exhibited positive relationships with 24-h PP (r=0.153, p=0.005 and r=0.251, p<0.001, respectively), day PP (r=0.150, p<0.01 and r=0.256, p<0.001, respectively) and night PP (r=0.148, p<0.01 and r=0.234, p<0.001, respectively). Multiple regression analysis models revealed that among components of ambulatory BP, only 24-h day PP was an independent predictor of LAVI (β=0.256, p<0.001). Conclusions: Ambulatory PP and particularly day PP but not circadian BP variation seems to determine the LA enlargement in hypertensive patients. Whether the abovementioned association contributes to the high cardiovascular risk observed in patients with wider day PP remains to be determined in future studies.