Organ-specific, age-dependent associations of steady-state pressures and pulsatile pressure wave components with end-organ measures

Abstract

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.