Subjects with borderline and established hypertension had higher residual forearm arterial resistance during reactive hyperemia (3.8 and 4.2 units) than normotensive subjects (2.3 units; p<0.01).
Observational (n=18)
p-value: p=<0.01
Factors determining vascular resistance were examined in 6 normotensive subjects (NT), 5 with established hypertension (EH) and diastolic pressures greater than 90 mmHg and 7 with borderline hypertension (BH) having pressures intermittently greater than 140/90 mmHg. Using plethysmography, we measured forearm blood flow (FBF), arterial resistance (FAR) and venous compliance (FVC) before and after autonomic blockade with propranolol 0.2 mg/kh, atropine 0.04 mg/kg and phentolamine 15 mg I.V. Subjects with EH had the highest baseline FBF. MAP was increased 18-22% after atropine and propranolol in all 3 groups. Phentolamine decreased MAP -8.9 +/- 2.1% in NT, -6.9 +/-1.2% in BH and -16.5 +/- 1.9% in EH (p less than 0.05). After total blockade, FAR in EH (32.4 +/- 4.8 units) was similar to FAR in TN (31.0 +/- 3.6 units) whereas that in BH remained high (50.2 +/- 3.8 units; p less than 0.01). Baseline FVC was highest in NT, intermediate in BH and lowest in EH and was not altered by autonomic blockade. Non-gravitational exercise for 6 min during upper arm arterial occlusion after autonomic blockade resulted in a residual FAR of 2.3 +/- 0.1 units in NT, 3.8 +/- 0.3 units in BH and 4.2 +/- 1.7 units in EH (p less than 0.01) during reactive hyperemia. Increased FAR in our subjects with BH and EH was probably due to structural vascular alterations. The greater increase in FAR and MAP in EH over that observed in BH has a sympathetic nervous system component.
Ogilvie et al. (1982) conducted an observational in Hypertension (n=18). Established and borderline hypertension vs. Normotensive subjects was evaluated on Residual forearm arterial resistance (FAR) during reactive hyperemia after autonomic blockade (p=<0.01). Subjects with borderline and established hypertension had higher residual forearm arterial resistance during reactive hyperemia (3.8 and 4.2 units) than normotensive subjects (2.3 units; p<0.01).