Venous abnormality in normotensive young men with a family history of hypertension.

Maximal vasodilator capacity of resistance vessels has been shown to be reduced in normotensive young men with a family history of hypertension. The present study attempted to examine whether venous distensibility is decreased in normotensive men with hypertensive relatives. The venous pressure-volume relationship was determined in the forearm with a water-filled plethysmograph in 17 normotensive young men with hypertensive relatives (mean blood pressure, 85 +/- 2 [SE] mm Hg; age, 22 +/- 1 years) and 18 young men with no family history of hypertension (mean blood pressure, 81 +/- 2 mm Hg; age, 22 +/- 1 years). The venous pressure-volume curve in men with hypertensive relatives as compared to that in men with no family history of hypertension was shifted toward the pressure axis (p less than 0.001). This findings suggests that venous distensibility is decreased in normotensive young men with hypertensive relatives. Administration of phentolamine, 1 mg/min i.v. for 5 minutes, did not alter venous distensibility, and venous distensibility after phentolamine administration was less in men with hypertensive relatives than in men with no family history (p less than 0.001), which suggests that decreased venous distensibility found in normotensive young men with hypertensive relatives was unlikely to be related to alpha-adrenergic mechanisms. These results suggest that normotensive young men with a family history of hypertension have vascular abnormalities that involve veins as well as arteries.