Increased carotid artery intimal-medial thickness in asymptomatic older subjects with exercise-induced myocardial ischemia.
BACKGROUND
Previous studies have shown an association between symptomatic coronary artery disease (CAD) and increased intimal-medial thickness of the common carotid artery (CCA IMT), a purported index of atherosclerosis. This study determines whether CCA IMT is increased in asymptomatic older subjects with an ischemic ST-segment response to treadmill exercise.


RESULTS
CCA IMT was measured by B-mode ultrasound in community-dwelling volunteers from the Baltimore Longitudinal Study of Aging, including 397 healthy subjects (age, 58.5+/-15.8 years) with normal ECG responses to maximum treadmill exercise, 72 asymptomatic subjects (age, 66.1+/-13.4 years) with exercise-induced horizontal or downsloping ST-segment depression >/=1 mm, and 38 subjects (age, 77. 4+/-7.8 years) with clinically manifest CAD as diagnosed by medical history and resting ECG. Forty-three subjects with abnormal exercise ECGs also underwent exercise thallium scintigraphy. Exercise-induced ST-segment depression was associated with increased IMT (P<0.0001) independent of age and manifest CAD. After adjustment for age, IMT values progressively increased from healthy subjects to asymptomatic subjects with positive exercise ECG alone to those with concordant positive ECG and thallium scintigraphic findings who had virtually identical IMT to subjects with manifest CAD. Each 0.1-mm increase in IMT was associated with a 1.91-fold (95% CI, 1.46 to 2.50; P<0.0001) increased risk for concordant positive exercise tests or manifest CAD, independent of other significant predictors of CAD.


CONCLUSIONS
CCA IMT is increased in older subjects with asymptomatic myocardial ischemia as evidenced by exercise ECG alone or in combination with thallium scan. Carotid ultrasound may help to identify asymptomatic individuals with CAD.
Nagai
Y
Y
Laboratory of Clinical Investigation, Gerontology Research Center, National Institute on Aging, National Institutes of Health, Baltimore, Md, USA.
Metter
E J
EJ
Earley
C J
CJ
Kemper
M K
MK
Becker
L C
LC
Lakatta
E G
EG
Fleg
J L
JL
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002339:Carotid Arteries / Q000000981:diagnostic imaging / Q000473:pathology*; D003327:Coronary Disease / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000473:pathology; D005080:Exercise Test / Q000009:adverse effects*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000209:etiology*; D011237:Predictive Value of Tests; D011877:Radionuclide Imaging; D012307:Risk Factors; D013793:Thallium; D017539:Tunica Intima / Q000000981:diagnostic imaging / Q000473:pathology*; D017540:Tunica Media / Q000000981:diagnostic imaging / Q000473:pathology*; D014463:Ultrasonography
D013793:Thallium