Abstract

ORTHOSTATIC BLOOD PRESSURE IN PRIMARY HYPERTENSION

F.Z.Milouk., D.Benchakroune., El Bakkali., Y.Radjab2., A.Lachhab., S.Aboudrar,H.Benjelloun

Abstract

Background: Measurements of blood pressure (BP) are usually done on supine position. Studies on orthostatic BP (Ortho BP) in hypertension (HT) would be of interest. The objective of this work is to assess the Ortho BP in hypertensive patients. Patients and methods : This prospective study included a group of 121 primary hypertensive patients (mean age: 54 years). Ortho BP was recorded for 10 minutes at the rhythm of 3 measurements per minute and was compared to the mean value of supine preorthostatic BP (mean Preortho BP). According to the changes in Ortho BP, three subgroups of primary hypertensive patients were selected as follows: Subgroup A: Ortho BP was higher than mean Preortho BP by 10 mm Hg or more. Subgroup B: Ortho BP was lower than mean Preortho BP by 20 mmHg or more. Subgroup C: there were no significant pathologic changes in Ortho BP compared to mean Preortho BP : -20 mm Hg < (Ortho BP - mean Preortho BP) < + 10 mmHg. Results : supine mean BP was 154.2 ± 12.7 mmHg while orthostatic mean BP, not including patients with orthostatic hypotension, was 172,0 ± 16.5 mmHg. In orthostatic position, 22,3 % of hypertensive patients showed an increase of their BP, ΔBP equal or higher than 10 mmHg, and 14.9 % showed orthostatic hypotension (OH). Also, 2/3 of patients mantained or increased their BP at orthostatism. Discussion: the increase in Ortho BP could be explained by sympathetic hyperactivity. Conclusion: orthostatic test (OT) would be performed in all patients with high BP, in order to detect associated orthostatic HT or OH.

Keywords: orthostatic test, sympathetic nerve activity, essential hypertension, autonomic nervous system, orthostatic hypotension, orthostatic blood pressure.