title: Acute reduction of blood pressure by nitroglycerin does not normalize large artery stiffness in essential hypertension.
abstract: Stiffness of large elastic arteries is elevated in subjects with hypertension, an effect that could potentially be explained by increased distending pressure. We examined effects of an acute change in blood pressure on carotid-femoral pulse wave velocity and carotid artery distensibility (inversely related to stiffness) in normotensive control subjects (n=20, mean age 42) with mean arterial pressure (MAP) 84+/-1.7 mm Hg (mean+/-SE) and subjects with essential hypertension (n=20, mean age 45, MAP 104+/-2.0 mm Hg). Normotensive subjects received intravenous nitroglycerin (NTG) and angiotensin II to lower/increase blood pressure. Hypertensive subjects received NTG to lower blood pressure. Pulse wave velocity was 24% (95% CI: 12% to 35%) higher and carotid distensibility 47% (95% CI: 32% to 63%) lower in hypertensive subjects compared with controls. In normotensive subjects, acute changes in blood pressure produced expected changes in stiffness. However, in hypertensive subjects, despite reducing MAP by 22 mm Hg to the same level as in normotensive subjects, there was no detectable reduction in arterial stiffness: pulse wave velocity remained 24% (95% CI: 10% to 38%) higher and carotid distensibility 48% (95% CI: 31% to 63%) lower in hypertensive compared with normotensive subjects. Because blood pressure-independent effects of NTG are, if anything, to reduce stiffness, these results indicate that elevated carotid and aortic stiffness in hypertensive subjects is not explained by elevated blood pressure but relates to structural change in the arterial wall.
authors.affiliation: Cardiovascular Division, King's College London School of Medicine, St Thomas' Hospital, London, United Kingdom.
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Stewart
authors.forename: Benyu
authors.initials: B
authors.lastname: Jiang
authors.forename: Sandrine C
authors.initials: SC
authors.lastname: Millasseau
authors.forename: James M
authors.initials: JM
authors.lastname: Ritter
authors.forename: Philip J
authors.initials: PJ
authors.lastname: Chowienczyk
mesh_terms: D000328:Adult; D001783:Blood Flow Velocity; D001794:Blood Pressure / Q000187:drug effects*; D002339:Carotid Arteries / Q000503:physiopathology*; D016022:Case-Control Studies; D003187:Compliance; D003971:Diastole; D005260:Female; D005263:Femoral Artery / Q000503:physiopathology*; D006801:Humans; D006973:Hypertension / Q000188:drug therapy* / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D005996:Nitroglycerin / Q000627:therapeutic use*; D011674:Pulse; D013997:Time Factors; D014665:Vasodilator Agents / Q000627:therapeutic use*
chemical_list: D014665:Vasodilator Agents; D005996:Nitroglycerin