Relationship between augmentation index obtained from carotid and radial artery pressure waveforms

Objective Increased aortic and carotid arterial augmentation index (AT) has been directly linked with cardiovascular disease risk, mortality and morbidity. The aim of this study was to examine whether Al obtained directly from radial artery pressure waveforms (radial Al) can provide information comparable with carotid arterial Al measurements. Methods In a cross-sectional study of 204 apparently healthy subjects (88 men and 116 women) aged 19-76 years (51 +/- 15 years, mean +/- SD), carotid Al [(second peak carotid systolic pressure-first peak carotid systolic pressure)/carotid pulse pressure*100] and radial Al [(second peak radial systolic pressure-diastolic pressure)/(first peak radial systolic pressure-diastolic pressure)*100] were measured using applanation tonometry. Results Radial Al was strongly correlated with carotid Al (r=0.86, P < 0.0001, SD of difference 10.0%), although radial Al was consistently approximately 66% higher than carotid Al. In 16 apparently healthy young adults (11 men and five women, aged 23 +/- 3 years) handgrip exercise was immediately followed by post-exercise muscle ischaemia (PEMI) to compare changes in carotid and radial Al during increased sympathetic nervous activity PEMI caused parallel increases in carotid and radial Al (26 and 19%). Accordingly, changes in radial Al with PEMI were strongly correlated with corresponding changes in carotid Al (r=0.86, P < 0.0001, SD of difference 7.3%). Conclusion These results suggest that Al obtained directly from radial arterial pressure waveforms could provide equivalent information to carotid arterial Al, and has potential as a surrogate marker of cardiovascular disease. J Hypertens 25:375-381 (c) 2007 Lippincott Williams & Wilkins.