Haemorheology in adolescent hypertensives.

Fifty-three untreated borderline hypertensives and 73 normotensives were randomly selected from 1342 adolescents (age range 23-27 years) who were examined in 1975, 1976 and 1980 in an epidemiological study. Blood pressure was 127.2 +/- 1.0/79.0 +/- 0.8 mmHg in normotensives and 147.2 +/- 1.6/93.7 +/- 1.1 mmHg in hypertensives (P < 0.001). Erythrocyte deformability was measured with a positive pressure filter system (pore diameter 5 microns) at 37 degrees C. Erythrocyte deformability was significantly increased in hypertensives with a value of 1.77 +/- 0.05, compared with 1.64 +/- 0.04 in normotensives (P < 0.05). No difference in apparent whole blood viscosity, haematocrit and plasma fibrinogen was measurable between the groups. Although plasma noradrenaline and adrenaline concentration at rest and after 3 min standing were not different, excretion of urinary catecholamines was significantly elevated in hypertensives with 155.0 +/- 3.3 micrograms/24 h (normotensives: 100.7 +/- 5.3 micrograms/24 h; P < 0.001).