Geometrical measures of retinal arterioles by ethnic group.

<p>Values are mean [95% confidence interval] either unadjusted or ^§ following adjustment for age, sex, systolic blood pressure, heart rate and diabetes. Abbreviations: LDR, length diameter ratio.</p

Geometrical measures of retinal venules by ethnic group.

<p>Values are mean [95% confidence interval] either unadjusted or ^§ following adjustment for age, sex, body mass index, systolic blood pressure, heart rate, smoking and diabetes. Abbreviations: AVR, arterio-venular ratio; LDR, length diameter ratio.</p

Characteristics of the individuals studied.

<p>Data for men and women are also shown separately.</p><p>Data are mean (SD); p values were calculated using a Student’s t-test comparing women and men. AIx, augmentation index; BMI, body mass index; cSBP, central systolic pressure; DBP, diastolic blood pressure; HR, heart rate, Pb/Pf, the ratio of forward to backward pressure; SBP, systolic pressure; T₁, the time difference between the foot and the shoulder of the waveform; WRI, wave reflection index.</p

Scatterplots of the relationship between age and various indices.

<p>A) Age vs. AIx B) Age vs, Log wave reflection index (WRI) and C) Age vs. peak backward/peak forward pressure (P_b/P_f). Regression lines are derived from data pooled by gender but data points for men (○) and women (•) are indicated separately.</p

Wave intensity analysis and pressure separation of the 3 different types of pressure waveform.

<p>The three types of pressure waveform (A, B, C) and their respective augmentation indices (AIx) are shown. The magnitude of the pressure and wave intensity traces have been scaled equally to allow comparison of morphology. Three principal wave S, c⁻₁ and D, forward pressure (P_f) backward pressure (P_b) and the shoulder point (P_s) are indicated.</p

Correlations between magnitude and timings of various indices of wave reflection and height.

<p>AIx, augmentation index; P_b backward pressure; P_b/P_f, the ratio of forward to backward pressure; T_s, the time of the shoulder of the waveform; WRI, wave reflection index. Data are Pearson’s correlation coefficients. Data are Pearson’s correlation coefficients.</p

Scatterplots of the relationship between age and wave or waveform timings.

<p>A) time of the shoulder (Ts), B) time of the peak of the reflected wave, c⁻₁ and C) time of P_b. Regression lines are derived from data pooled by gender but data points for men (○) and women (•) are indicated separately.</p

Examples illustrating definitions of measured parameters and indices.

<p>A) pressure waveform (blue) modified from <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0059371#pone.0059371-Laurent1" target="_blank">[31]</a> and indicating measured parameters and showing separated forward (black) and backward (red) components. Total pressure is the sum of forward and backward pressure. B) wave intensity analysis, showing principal waves and timings. Wave reflection index (WRI) is calculated as the ratio of the area under c⁻₁ to the area under S wave. Abbreviations c⁻₁, backwards (reflected) compression wave; D, forward decompression wave in late systole; d⁺₁, mid-systolic forward decompression wave, presumed to be a re-reflection of the backward reflected compression wave, c⁻₁; P_b, peak backward pressure; P_f, peak forward pressure; S, forward compression wave associated with ejection in early systole; T_f, time of the foot of the pressure waveform; T_s, time of the shoulder on the pressure waveform; T₁, the time difference between foot and shoulder (T_s−T_f).</p

Comparison of measures of reflection between type A, B and C waveforms.

<p>Data are mean (95% confidence intervals). P values were calculated by analysis of variance.</p