The relationship between aortic augmentation index and pulse wave velocity: an invasive study.
OBJECTIVE
The aortic augmentation index (AI) and aortic pulse wave velocity (PWV) are known to be indicators of arterial stiffness. However, it is not clear whether aortic AI and PWV reflect aortic stiffness in similar ways. We investigated the relationship between aortic AI and PWV by measuring them directly using a catheter technique.


METHODS
Forty-one patients, aged 34-79 years, were studied during diagnostic cardiac catheterization. Aortic pressures were measured using a catheter-tip manometer at two points, one in the ascending aorta and one 40 cm distally in the descending aorta. Aortic AI was defined as the difference between early and late pressure peaks divided by the pulse pressure of the ascending aorta. Aortic PWV was calculated as the distance between the two measuring sites divided by the transit time. We also examined the effects of vasodilatation on AI and PWV by the intra-aortic administration of nitroglycerin in 15 patients.


RESULTS
AI was significantly related to age, systolic aortic pressure, heart rate, left ventricular ejection time, and height. Aortic PWV showed an association only with age and systolic aortic pressure. There was no significant relationship between aortic AI and PWV (r = 0.28, NS). Nitroglycerin also produced different effects on aortic AI and PWV: aortic AI was significantly decreased (-0.17, P < 0.01) after nitroglycerin, but PWV remained unchanged (+0.4 m/s, NS).


CONCLUSIONS
Aortic AI and PWV cannot be used interchangeably as an index of arterial stiffness. AI may not be a true indicator of arterial stiffness, but an index of wave reflection including PWV.
Sakurai
Masato
M
Department of Cardiology, Mie University of Medicine, Mie, Japan.
Yamakado
Tetsu
T
Kurachi
Hideshi
H
Kato
Takaaki
T
Kuroda
Kenji
K
Ishisu
Ryoichi
R
Okamoto
Shinya
S
Isaka
Naoki
N
Nakano
Takeshi
T
Ito
Masaaki
M
D000328:Adult; D000368:Aged; D001011:Aorta / Q000503:physiopathology*; D001795:Blood Pressure Determination / Q000295:instrumentation / Q000379:methods*; D006328:Cardiac Catheterization; D003324:Coronary Artery Disease / Q000503:physiopathology; D005260:Female; D006801:Humans; D006973:Hypertension / Q000503:physiopathology; D008297:Male; D008365:Manometry / Q000009:adverse effects / Q000379:methods*; D008875:Middle Aged; D005996:Nitroglycerin / Q000494:pharmacology; D011673:Pulsatile Flow / Q000502:physiology*; D015203:Reproducibility of Results; D014665:Vasodilator Agents / Q000494:pharmacology
D014665:Vasodilator Agents; D005996:Nitroglycerin