Resumen en español

Recently, an arterial stiffness index called AASI (Ambulatory Arterial Stiffness Index) calculated from ambulatory blood pressure measurements during 24 hours was proposed. The associations with arterial stiffness and the pressure dispersion dependence remain under discussion. We propose to study these controversies in a statistical model framework. A simulation was performed including values similar to the ones in patients with normal, rigid and compliant arteries. Three exponential curves of pressure-diameter were simulated. Based on diameters randomly generated following normal distributions, systolic and diastolic pressures were calculated in a 24h parametric time. AASI was calculated as one minus the slope of the regression of systolic to diastolic pressure. The AASI for the normal group was 0,42, increased to 0,50 in the rigid group and decreased to 0,34 in the compliant case (always r2>0,9). A dispersion decrease in the pressure values was followed by an r2 decrease in the diastolic vs systolic pressure regression, artifi cially increasing AASI. For the fi rst time the non-linearity of the arterial wall helps to explain the association of AASI with a stiffness index. The simulation corroborates that 24 h pressure variability conditions AASI values due to its statistical nature.