PP.37.01] TIME TO PEAK OF THE AORTIC FORWARD WAVE DETERMINES THE IMPACT OF AORTIC BACKWARD WAVE AND PULSE PRESSURES ON LEFT VENTRICULAR MASS

Abstract

Objective: Although aortic backward waves and hence pulse pressure are well-recognised determinants of cardiovascular damage beyond brachial pressures, these effects are inconsistent across studies. We aimed to assess whether an extended time to peak of aortic forward wave (Ft) or early wave reflection time (Rt) increase the chances of backward wave pressures (Pb) and hence central aortic pulse pressure (PPc) modifying end-organ effects. Design and method: In 812 adult participants from a community sample we assessed aortic haemodynamics (SphygmoCor software and wave separation analysis) and left ventricular mass index (LVMI) (echocardiography). Results: An interaction between Ft and Pb was independently associated with aortic augmented pressure (Pa) (p < 0.02), PPc (p < 0.005), LVMI (p < 0.0001) and LV hypertrophy (LVH) (p = 0.001). The Ft-Pb interaction translated into a stepwise increase in the independent association between Pb and Pa or PPc across quartiles of Ft (p < 0.02 for comparison of slopes of relations). Furthermore, the Ft-Pb interaction translated into an increase in the independent association between PPc or Pb and LVMI (p < 0.0001 for comparison of slopes and strength of relations) or LVH (p < 0.01 for comparisons of Odds ratios), but not between forward wave pressures and LVMI or LVH across quartiles of Ft. A markedly better ability of Pb and PPc, but not forward wave pressures to detect LVH was noted in the highest as compared to the first three quartiles of Ft (p < 0.01). In contrast, Rt failed to influence the impact of Pb or PPc on LVMI. Conclusions: Time to peak of aortic forward wave, but not early wave reflection markedly influences the impact of aortic backward wave pressure and hence PP on LVMI and LVH in adults. Hence, the adverse effects of aortic backward wave and hence pulse pressures may be strongly determined by forward wave timing.