Averaged Doppler blood flow signals of the supratrochlear artery were used to evaluate age-dependent parameters and ratios in 102 patients with essential hypertension as the only risk factor, and in 74 normotensive healthy volunteers. The first and second systolic peak values (A and B), the minimal value in between A and B (K), the value of the incisura (I), the value of the diastolic peak (D), the time interval between the R-peak of the ECG and A (ti), the duration of the systolic rising phase (ts), and the time interval between the R-peak of the ECG and the footpoint of the systolic rising phase (ti-ts) were used as parameters, and (A-K)/A, A/B, and (D-I)/A were used as ratios. The (A-K)/A-ratio and A/B decreased with age and differed significantly between hypertensive patients 41 to 70 years of age and normotensive controls, between ineffectively treated hypertensive patients 31 to 70 years of age and normotensive controls, and between ineffectively treated hypertensive patients with normalized blood pressure under an antihypertensive regimen in the age group 41 to 60 year. B-values increased, I- and D-values did not change, the (D-I)/A-ratio decreased, the time interval (ti) and (ti-ts) decreased, and the duration of the systolic rising phase (ts) increased with age, but no significant difference was found for all these parameters and ratios between any comparable groups. Our findings suggest that the age-dependent pattern of blood flow signals may represent vascular alterations which are markedly accelerated in hypertensive patients as compared to age-matched normotensive controls.(ABSTRACT TRUNCATED AT 250 WORDS)