Carotid intima-media thickness and risk of cardiovascular events in high-risk patients. Results of the Osaka Follow-Up Study for Carotid Atherosclerosis 2 (OSACA2 Study).
OBJECTIVE
There is epidemiological evidence that increased carotid intima-media thickness (IMT) is a predictor of cardiovascular disease (CVD) events. However, the significance of carotid IMT in high-risk patients in whom risk factors are managed clinically has not been adequately investigated. The purpose of this study was to determine the usefulness of carotid IMT measurement in such patients.


METHODS
The study comprised 900 outpatients with cardiovascular risk factors or established atherosclerosis. Carotid IMT was calculated as the mean bilateral IMT of the common carotid artery, bifurcation, and internal carotid artery. Baseline vascular risk factors, medications, and history of CVD were recorded at the time of enrollment. The incidence of CVD events was determined prospectively.


RESULTS
During a mean follow-up period of 2.6 years, there were 64 CVD events. The relative risk (RR) of a CVD event increased with increased IMT. Association between CVD events and carotid IMT was significant after adjustment for risk factors and history of CVD, showing an increased risk per IMT tertile from the middle tertile (RR, 2.5; 95% confidence interval [CI]: 1.0-6.3) to the highest (RR, 3.6; 95% CI: 1.4-9.0). When patients with a history of CVD were excluded (n = 574), the predictive value of IMT was significant even after adjustment for risk factors (hazard ratio per 1 SD IMT increase was 1.57 [95% CI: 1.11-2.20]).


CONCLUSIONS
Carotid IMT is an independent predictor of vascular events in high-risk patients in whom risk factors are managed clinically.
Kitagawa
Kazuo
K
Stroke Division, Department of Cardiovascular Medicine, Osaka University Graduate School of Medicine, Osaka, Japan. kitagawa@medone.med.osaka-u.ac.jp
Hougaku
Hidetaka
H
Yamagami
Hiroshi
H
Hashimoto
Hiroyuki
H
Itoh
Taiji
T
Shimizu
Yoshiomi
Y
Takahashi
Daisuke
D
Murata
Shinji
S
Seike
Yujiro
Y
Kondo
Kimito
K
Hoshi
Taku
T
Furukado
Shigetaka
S
Abe
Yuko
Y
Yagita
Yoshiki
Y
Sakaguchi
Manabu
M
Tagaya
Masafumi
M
Etani
Hideki
H
Fukunaga
Ryuzo
R
Nagai
Yoji
Y
Matsumoto
Masayasu
M
Hori
Masatsugu
M
D000368:Aged; D050197:Atherosclerosis / Q000150:complications / Q000000981:diagnostic imaging* / Q000401:mortality; D002318:Cardiovascular Diseases / Q000000981:diagnostic imaging / Q000209:etiology* / Q000401:mortality; D017536:Carotid Artery, Common / Q000000981:diagnostic imaging*; D002343:Carotid Artery, Internal / Q000000981:diagnostic imaging*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D007564:Japan / Q000453:epidemiology; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D011446:Prospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D013997:Time Factors; D017539:Tunica Intima / Q000000981:diagnostic imaging*; D017540:Tunica Media / Q000000981:diagnostic imaging*; D014463:Ultrasonography