Relationship Between Peripheral Augmentation Index And Central Augmentation Index

Objective: To investigate the relationship between peripheral augmentation index (AI) and central AI, understand whether can peripheral AI reflex central AI well. To discuss the consistency between the direct central AI and the calculated central AI through peripheral artery. To test whether central AI is an independent risk factor of coronary heart disease.Methods: Sixty consecutive individuals who underwent coronary angiography in our ward during December 2007 and March 2008 were enrolled in this study. The artery pressure wave tracings were obtained at the upper segment of radial artery and the ascending aorta in the process of coronary angiography. Peripheral AI and central AI were calculated from the artery pressure wave tracings. The formula for peripheral AI is AIr=P2/P1, where P1 is the sum of the incident (ejected) wave and reflected wave amplitude, P2 is the peak of the reflected wave from the lower body minus end-diastolic pressure. The formula of central AI is AIa=(Ps-Pi)/(Ps-Pd), where Ps indicates the peak systolic pressure and Pi the inflection point that indicates the beginning upstroke of the reflected pressure wave, and Pd is minimum diastolic pressure. AIr and the AIa were obtained from three consecutive reflected waves and averaged.Result: (1) Linear simple regression analysis showed that there was significant correlation between peripheral AI and central AI (r=0.74, P<0.01). (2) The linear regression equation of central AI (y) and peripheral AI (x) is y=10.17+0.56x. There was no significant statistical difference between the central AI we measured directly and the central AI deduced from peripheral artery (p>0.05). (3) Logistic regression analysis showed that AI was an independent risk factor for coronary heart disease (odds ratio was 1.074, with 95% confidence interval (CI) 1.021-1.129).Conclusion: (1) There is good correlation between peripheral AI and central AI. Peripheral AI can reflex central AI well. (2) The deduced central AI through peripheral artery and that getting from central AI directly has good consistency. We can get reliable central AI by measuring peripheral artery tracings. (3) Central AI is an independent risk factor for coronary heart disease.