P-101: Timing of abdominal aortic pulse: a new echocardiogaphic index of arterial stiffness?

Arterial stiffness (AS) is a component of afterload, determinant of the degree of left ventricular hypertrophy. Some indexes of AS are provided by non invasive approach like ambulatory pressure monitoring (AMP). However we describe a new index, easy to obtain during a routine echocardiogram, the time of abdominal aortic pulse (QtAA). The aim of the study is to assess the correlations between QtAA and AS indexes and between QtAA and other indexes known to be correlated with AS indexes; to assess the inter and intra observer variability. Sixty consecutive patients with or without cardiac diseases were enrolled in a prospective study except those with a pace maker, left bundle block branch, atrial fibrillation. QtAA was defined as the delay between Q wave ECG and the foot of abdominal aortic pulse, determined by an echo Doppler (ED) in a sub costal approach. ED collected data like stroke index (SI), LV diameters and wall thickness. AMP collected usual pressure data (systolic, diastolic, mean, pulse, instantaneous and during 24h) and automatic assessment of the QKd interval (time between Q ECG and diastolic pressure sound). Burton index, an AS index, was defined as stroke index/pulse pressure. Values were mean plusminus SD. Relationships between various parameters were fitted by a linear function and intra observer variability was defined as the coefficient of variation (mean/SD), inter observer variability as QtAA assessments by two observers. QtAA was correlated with AS indexes like QKdi (n = 53, p < 0,001, r = 0,79), QKd24h (n = 47, p < 0,001, r = 0,64), Burton index (n = 52, p < 0,001, r = 0,51). QtAA was correlated with indexes which are usually correlated with AS indexes like systolic pressure (n = 58, p < 0,001, r = 0,52), pulse pressure (n = 58, p < 0,001, r = 0,59), LV mass (n = 55, p = 0,010, r = 0,35). The coefficient of variation was 6.3%, the inter observer variability was 6.1%. QtAA is an index well correlated with other arterial stiffness indexes, and easy to obtain during a routine echocardiogram. Further studies are needed to define normal values and its pathologic or physiologic variations, and during pharmacological interventions.