Vascular and baroreceptor abnormalities in young males with a family history of hypertension

Abstract

Vascular and baroreceptor abnormalities in 44 young males, mean age 21 years, comprising of offspring with (FH(+); n = 22) and without (FH(-); n = 22) hypertensive parents, were investigated. Peak forearm blood flow (FBF), which was defined as the highest blood flow obtained following reactive hyperaemia, was assessed using strain gauge plethysmography following 5 min of ischemia. Cardiopulmonary baroreceptor sensitivity was assessed using lower body negative pressure for 5 min at -20 mmHg and was determined by calculating change of stroke volume and forearm vascular resistance (FVR) to lower body negative pressure. Carotid baroreceptor sensitivity was assessed using neck suction at -20, -40, -60, and -80 mmHg and was calculated by dividing RR interval by systolic blood pressure. Augmentation index, a measure of wave reflection, was assessed using applanation tonometry and was calculated as the ratio of augmented pressure and pulse pressure. Peak FBF of FH(+) was 19% lower than the FH(-) (p = 0.02). Also FH(+) had 17% higher peak FVR compared to FH(-) (p = 0.04). However, there were no significant differences between groups for cardiopulmonary, carotid baroreceptor sensitivity, and augmentation index. These results suggest that peripheral vascular dysfunction appears earlier than abnormal baroreceptor sensitivity in young males with a family history of hypertension.

The effect of 4 weeks of aerobic exercise on vascular and baroreflex function of young men with a family history of hypertension

“…1,2,29 The present study did not have a FH À group against which the FH þ subjects could be compared, however, comparison of pre-test data with previous studies performed in the same laboratory 2 , using the same testing protocol, indicate that the current subjects possessed peripheral vascular aberrations commonly seen in FH þ subjects. For example, 75% of the current FH þ cohort had a peak FBF value below one s.d.…”

“…2 An arterial cuff was inflated to 200 mm Hg during the last minute. Peak blood flow was measured 5 s after release of venous cuff occlusion and every 10 s thereafter.…”

“…from the mean of FH À subjects of the same age. 2 Takeshita et al 1 have proposed that structural abnormalities in the vessels, rather than neurohumoral vasoconstrictor stimuli, explain the reduced vasodilatory capacity in FH þ subjects. A number of studies have shown that FH þ subjects possess peripheral vascular abnormalities that precede and contribute toward the development of hypertension.…”

“…However, results from previous research in our laboratory have confirmed that young FH þ typically possess vascular abnormalities compared with young FH À . 2 Another limitation was the self reported family history of hypertension by participants. Although this questionnaire has been used in previous published studies, more reliable measures, such as assessment of parent's blood pressure, should be used to identify family history of hypertension.…”

“…Men and women as young as 18 --19 years old with a family history of hypertension (FH þ ) were found to possess lower peak forearm blood flow 1,2 and high forearm vascular resistance 1,2 as well as reduced baroreflex sensitivity 3 than that of young individuals without a family history of hypertension (FH À ). It has also been shown that middle-aged offspring of hypertensive parents possessed greater arterial stiffness, assessed through augmentation index (AIx), compared with middle-aged individuals without a family history of hypertension.…”