Aim of this study was to assess the role of age-related vascular response in the onset of i.v. dipyridamole effects. The results of 129 patients who underwent a dipyridamole infusion were reviewed. The patients were divided into three according to age: 47 patients of less than 50 years (group I), 54 patients aged between 50 and 60 years (group II) and 28 patients of more than 60 years (group III). For each group heart frequency (HF) and systolic blood pressure (SBP) were considered in basal conditions, at the end of infusion and at the minimum value of SBP (SBP min); moreover the time in reaching SBP min was considered (time to SBP min). At the end of the infusion no significant changes in SBP were observed in all groups while the SBP min value reached from group III were significantly lower than basal (142.6 +/- 20.4 mmHg, p less than 0.02). The HF, without significant differences among the three groups in basal conditions, increased significantly at the end of infusion only in group I and II, with a more significant increase in group I at the time of SBP min with respect to groups II and III. The group 3 showed moreover, a significant longer time to SBP min (286 +/- 208 sec) respect to the group I and II (145 +/- 130 and 160 +/- 177 sec respectively) (p less than 0.02). From these data it can resume that age could be a factor to determine hemodynamic response to intravenous dipyridamole.