Organ-Specific, Age-Dependent Associations of Steady-State Pressures and Pulsatile Pressure Wave Components With End-Organ Measures

BACKGROUND The contribution of steady-state pressures and the forward (Pf) and backward (reflected) (Pb) wave pressure components of pulse pressure to risk prediction have produced contrasting results. We hypothesized that the independent contribution of steady-state pressures (mean arterial pressure [MAP]), Pf and Pb, to cardiovascular damage is organ specific and age dependent. METHODS In 1,384 black South Africans from a community sample, we identified independent relations between MAP, Pf, or Pb (applanation tonometry and SphygmoCor software) and left ventricular mass index (LVMI) (n = 997) (echocardiography), carotid intima-media thickness (IMT) (n = 804) (B-mode ultrasound), or aortic pulse wave velocity (PWV) (n = 1,217). RESULTS Independent of risk factors, relations between Pf and IMT were noted in those over 50 years (P < 0.02), whereas in those less than 50 years, MAP (P < 0.005) was independently associated with IMT. Pb failed to show independent relations with IMT at any age (P > 0.37) In contrast, independent relations between Pb and LVMI were noted in those less than (P < 0.0001), and greater than (P < 0.02) 50 years, whereas MAP was not independently associated with LVMI at any age (P > 0.07) and Pf tended to show significant relations only in the elderly (P = 0.05). Moreover, although MAP (P < 0.005) and Pb (P < 0.01) showed independent relations with PWV at any age, Pf failed to show independent relations (P > 0.10). CONCLUSION Independent of confounders, steady-state and aortic Pf and Pb show associations with end-organ measures that are organ specific and age dependent.