Abstract 17338: Determinants of Pressure Wave Reflection: Characterization by the Transit-time Independent Reflected Wave Amplitude
Objectives: The clinical value of increased arterial wave reflection intensity, usually assessed by the transit-time dependent augmentation index (AI) and augmented pressure (Pa) may have been underestimated. We investigated the determinants of amplitude of the reflected wave (Pb), which is independent of the transit-time and has been shown to predict cardiovascular mortality in the general population.
Methods: A total of 180 (117 male, mean age 68 year old) patients were recruited. Carotid pressure waveforms derived by tonometry at baseline and 3 minutes after administration of sublingual nitroglycerin (NTG) were calibrated by brachial mean (MBP) and diastolic blood pressure to yield central systolic and pulse pressures, and were then decomposed into forward waves and backward waves using the triangulation flow method. Pa and AI were also calculated by the conventional waveform analysis. Brachial-ankle pulse wave velocity (baPWV) and the ratio of pre-ejection period/ejection time (PEP/ET) were measured simultaneously.
Results: Pb, Pa, and AI correlated significantly with age, all blood pressure variables, heart rate, height, and PEP/ET. In contrast, Pa and AI but not Pb correlated significantly with sex, body mass index, and waist circumference. In addition, Pb and Pa but not AI correlated significantly with baPWV. By stepwise multivariate analysis, independent determinants of Pb included brachial mean blood pressure (β=0.56, P<0.001), heart rate (β=-0.29, P<0.001), age (β=0.20, P<0.001), PEP/ET (β=-0.16, P=0.004), and height (β=-0.13, P=0.018). RWTT, body mass index, and sex were significant independent determinants of Pa and AI but did not contribute to Pb. Change of Pb but not Pa or AI significantly predicted the changes of carotid systolic (r=0.550, P<0.001) and pulse pressure (r=0.618, P<0.001) after NTG.(Figure 1)
Conclusions: Determinants of Pb differ from those of cAI and Pa. Pb is independent of sex and RWTT.
- © 2010 by American Heart Association, Inc.