Aortic augmentation index: reference values in a large unselected population by means of the SphygmoCor device.
BACKGROUND
Arterial stiffness and pulse wave reflection are associated with cardiovascular disease (CVD). Pulse wave analyses (PWAs) allow the estimation of the central augmentation index (AIx), a measurement of pulse wave reflection. To understand the predictive role of AIx, reference values for AIx are needed.


METHODS
This population study is based on 4,561 subjects from The Copenhagen City Heart Study, an ongoing epidemiological survey started in 1976, including subjects randomly chosen from the population in Copenhagen, Denmark. We calculated and internally validated reference values of AIx measured by the SphygmoCor device in a cohort without known CVD or diabetes, and with low risk of CVD according to HeartScore using gender-specific multiple regression analyses adjusting for age, heart rate, and height.


RESULTS
AIx was significantly higher in women than in men, 30% vs. 22%, (P < 0.001) and the increase in AIx with age was curvilinear. There were 972 subjects in the low-risk cohort with mean AIx 28% in women (N = 565) and 18% in men (N = 407) (P < 0.001). We report the following internally validated reference equations for AIx: men: AIx = 79.20 + 0.63 (age) - 0.002 (age(2)) - 0.28 (heart rate) - 0.39 (height). Women: AIx = 56.28 + 0.90 (age) - 0.005 (age(2)) - 0.34 (heart rate) - 0.24 (height). AIx appeared to increase with increasing risk of CVD according to HeartScore.


CONCLUSIONS
We report a novel and internally validated gender-specific equation including age, heart rate, and height to calculate reference values for AIx.
Janner
Julie H
JH
Department of Cardiology and Respiratory Medicine, Hvidovre University Hospital, Hvidovre, Denmark. julie.janner@hvh.regionh.dk
Godtfredsen
Nina S
NS
Ladelund
Steen
S
Vestbo
Jørgen
J
Prescott
Eva
E
D000328:Adult; D000367:Age Factors; D000368:Aged; D000465:Algorithms; D001158:Arteries / Q000502:physiology*; D001827:Body Height / Q000502:physiology; D002318:Cardiovascular Diseases / Q000453:epidemiology / Q000503:physiopathology; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D003718:Denmark / Q000453:epidemiology; D005260:Female; D006306:Health Surveys; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008055:Lipids / Q000097:blood; D008297:Male; D008875:Middle Aged; D011153:Population; D011237:Predictive Value of Tests; D011673:Pulsatile Flow / Q000502:physiology*; D012016:Reference Values; D012737:Sex Factors; D012907:Smoking / Q000453:epidemiology; D012959:Socioeconomic Factors
D008055:Lipids