title: Dominance of the forward compression wave in determining pulsatile components of blood pressure: similarities between inotropic stimulation and essential hypertension.
abstract: Pulsatile components of blood pressure may arise from forward (ventricular generated) or backward wave travel in the arterial tree. The objective of this study was to determine the relative contributions of forward and backward waves to pulsatility. We used wave intensity and wave separation analysis to determine pulsatile components of blood pressure during inotropic and vasopressor stimulation by dobutamine and norepinephrine in normotensive subjects and compared pulse pressure components in hypertensive (mean±SD, 48.8±11.3 years; 165±26.6/99±14.2 mm Hg) and normotensive subjects (52.2±12.6 years; 120±14.2/71±8.2 mm Hg). Dobutamine (7.5 μg/kg per minute) increased the forward compression wave generated by the ventricle and increased pulse pressure from 36.8±3.7 to 59.0±3.4 mm Hg (mean±SE) but had no significant effect on mean arterial pressure or the midsystolic backward compression wave. By contrast, norepinephrine (50 ng/kg per minute) had no significant effect on the forward compression wave but increased the midsystolic backward compression wave. Despite this increase in the backward compression wave, and an increase in mean arterial pressure, norepinephrine increased central pulse pressure less than dobutamine (increases of 22.1±3.8 and 7.2±2.8 mm Hg for dobutamine and norepinephrine, respectively; P<0.02). An elevated forward wave component (mean±SE, 50.4±3.4 versus 35.2±1.8 mm Hg, in hypertensive and normotensive subjects, respectively; P<0.001) accounted for approximately two thirds of the total difference in central pulse pressures between hypertensive and normotensive subjects. Increased central pulse pressure during inotropic stimulation and in essential hypertension results primarily from the forward compression wave.
authors.affiliation: From the British Heart Foundation Centre (H.F., A.G., S.B., B.J., Y.L., P.C.) and Division of Imaging Sciences and Biomedical Engineering (S.E., J.A.), King's College London, London, United Kingdom; and Guy's and St Thomas Foundation Trust Hospital, London, United Kingdom (B.C.).
authors.forename: Henry
authors.initials: H
authors.lastname: Fok
authors.affiliation: From the British Heart Foundation Centre (H.F., A.G., S.B., B.J., Y.L., P.C.) and Division of Imaging Sciences and Biomedical Engineering (S.E., J.A.), King's College London, London, United Kingdom; and Guy's and St Thomas Foundation Trust Hospital, London, United Kingdom (B.C.).
authors.forename: Antoine
authors.initials: A
authors.lastname: Guilcher
authors.affiliation: From the British Heart Foundation Centre (H.F., A.G., S.B., B.J., Y.L., P.C.) and Division of Imaging Sciences and Biomedical Engineering (S.E., J.A.), King's College London, London, United Kingdom; and Guy's and St Thomas Foundation Trust Hospital, London, United Kingdom (B.C.).
authors.forename: Sally
authors.initials: S
authors.lastname: Brett
authors.affiliation: From the British Heart Foundation Centre (H.F., A.G., S.B., B.J., Y.L., P.C.) and Division of Imaging Sciences and Biomedical Engineering (S.E., J.A.), King's College London, London, United Kingdom; and Guy's and St Thomas Foundation Trust Hospital, London, United Kingdom (B.C.).
authors.forename: Benyu
authors.initials: B
authors.lastname: Jiang
authors.affiliation: From the British Heart Foundation Centre (H.F., A.G., S.B., B.J., Y.L., P.C.) and Division of Imaging Sciences and Biomedical Engineering (S.E., J.A.), King's College London, London, United Kingdom; and Guy's and St Thomas Foundation Trust Hospital, London, United Kingdom (B.C.).
authors.forename: Ye
authors.initials: Y
authors.lastname: Li
authors.affiliation: From the British Heart Foundation Centre (H.F., A.G., S.B., B.J., Y.L., P.C.) and Division of Imaging Sciences and Biomedical Engineering (S.E., J.A.), King's College London, London, United Kingdom; and Guy's and St Thomas Foundation Trust Hospital, London, United Kingdom (B.C.).
authors.forename: Sally
authors.initials: S
authors.lastname: Epstein
authors.affiliation: From the British Heart Foundation Centre (H.F., A.G., S.B., B.J., Y.L., P.C.) and Division of Imaging Sciences and Biomedical Engineering (S.E., J.A.), King's College London, London, United Kingdom; and Guy's and St Thomas Foundation Trust Hospital, London, United Kingdom (B.C.).
authors.forename: Jordi
authors.initials: J
authors.lastname: Alastruey
authors.affiliation: From the British Heart Foundation Centre (H.F., A.G., S.B., B.J., Y.L., P.C.) and Division of Imaging Sciences and Biomedical Engineering (S.E., J.A.), King's College London, London, United Kingdom; and Guy's and St Thomas Foundation Trust Hospital, London, United Kingdom (B.C.).
authors.forename: Brian
authors.initials: B
authors.lastname: Clapp
authors.affiliation: From the British Heart Foundation Centre (H.F., A.G., S.B., B.J., Y.L., P.C.) and Division of Imaging Sciences and Biomedical Engineering (S.E., J.A.), King's College London, London, United Kingdom; and Guy's and St Thomas Foundation Trust Hospital, London, United Kingdom (B.C.). phil.chowienczyk@kcl.ac.uk.
authors.forename: Phil
authors.initials: P
authors.lastname: Chowienczyk
mesh_terms: D000328:Adult; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology*; D002316:Cardiotonic Agents / Q000494:pharmacology*; D016022:Case-Control Studies; D004280:Dobutamine / Q000494:pharmacology; D000075222:Essential Hypertension; D005260:Female; D006439:Hemodynamics / Q000187:drug effects / Q000502:physiology; D006801:Humans; D006973:Hypertension / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D009119:Muscle Contraction / Q000187:drug effects* / Q000502:physiology; D009131:Muscle, Smooth, Vascular / Q000187:drug effects* / Q000502:physiology; D009638:Norepinephrine / Q000494:pharmacology; D011673:Pulsatile Flow / Q000187:drug effects / Q000502:physiology*; D063177:Pulse Wave Analysis; D014662:Vasoconstrictor Agents / Q000494:pharmacology
chemical_list: D002316:Cardiotonic Agents; D014662:Vasoconstrictor Agents; D004280:Dobutamine; D009638:Norepinephrine
keywords: hypertension; pulse pressure; pulse wave analysis