Limited maximal vasodilator capacity of forearm resistance vessels in normotensive young men with a familial predisposition to hypertension.

The study was performed to determine whether there is a structural vascular abnormality in normotensive subjects with hypertensive relatives. We examined maximal vasodilator capacity of forearm resistance vessels in 23 normotensive young men (mean blood pressure 94 +/- 0.4 mm Hg, mean +/- SE) with hypertensive relatives (age 24 +/- 0.1 years) and in 17 normotensive subjects (mean blood pressure 85 +/- 0.4 mm Hg) with no family history of hypertension (age 24 +/- 0.1 years). Maximal vasodilator capacity was examined by measuring minimal vascular resistance during peak reactive hyperemia after release from 10 minutes of arterial occlusion. Minimal forearm vascular resistance after release from 10 minutes of arterial occlusion was 25% higher (P less than 0.02) in subjects with hypertensive relatives (2.0 +/- 0.02 units) than that in subjects with no family history (1.5 +/- 0.01) units. We confirmed the previous findings that increasing metabolic vasodilator stimulus by performing intermittent handgrip exercise during 10 minutes of arterial occlusion did not augment peak dilation. This suggests that 10 minutes of arterial occlusion produced maximal vasodilation. Forearm vascular responses to ice on the forehead was greater in subjects with hypertensive relatives than those in subjects with no family history. These results suggest that there may be a structural abnormality in the forearm resistance vessels in normotensive subjects with family history of hypertension.