Prevalence of carotid stenosis and silent myocardial ischemia in asymptomatic subjects with a low ankle-brachial index.
OBJECTIVE
Subjects with symptomatic peripheral artery disease (PAD) have an elevated prevalence of carotid stenosis and of silent myocardial ischaemia. As such, clinical guidelines advocate the detection of sub-clinical vascular disease in this population. However, the prevalence of occult vascular disease in asymptomatic patients with a low ankle-brachial index (ABI) has not been previously evaluated.


METHODS
Cross-sectional study in five primary care centres for patients' selection and two University Hospitals for further assessment. Subjects were 1070 asymptomatic individuals between 60 and 80 years of age with at least two cardiovascular risk factors, selected for ankle-brachial index measurement. Eighty five subjects with an ABI <0.9 and an equal number of controls, matched for age, gender, diabetes, and smoking habit, and with a normal ABI, were referred to the Hospital for carotid ultrasound and exercise stress tests (EST). Main outcome measures were prevalence of a carotid stenosis >50% and an abnormal EST.


RESULTS
The prevalence of a low ABI in the overall population was 9.1%. A carotid stenosis >50% was detected in 14.3% of the subjects with a low ABI and in 4.7% of the control subjects (Odds Ratio [OR]: 3.37; 95% Confidence Interval [CI]: 1.04-10.93, P = .033). The prevalence of a positive EST test was 16.2% in those with a low ABI and 10.5% in control subjects (OR: 1.65; 95% CI: 0.63-4.29, P = .309). These prevalences were higher in older subjects, in those with hypertension or diabetes, or in those with dyslipidemia.


CONCLUSIONS
Our results indicate that in high-risk asymptomatic subjects >60 years of age, the presence of an ABI <0.9 identifies a subgroup of the population with an increased prevalence of carotid stenosis and of silent myocardial ischemia and, as such, are candidates for closer follow-up.
Mostaza
Jose M
JM
Unidad de Arteriosclerosis, Hospital Carlos III, Madrid, Spain. jmostaza.hciiii@salud.madrid.org
González-Juanatey
Jose R
JR
Castillo
Jose
J
Lahoz
Carlos
C
Fernández-Villaverde
Jose M
JM
Maestro-Saavedra
Francisco J
FJ
D000368:Aged; D000842:Ankle / Q000098:blood supply*; D001794:Blood Pressure; D001916:Brachial Artery / Q000503:physiopathology*; D016893:Carotid Stenosis / Q000000981:diagnostic imaging / Q000453:epidemiology* / Q000209:etiology / Q000503:physiopathology; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D005080:Exercise Test; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000453:epidemiology* / Q000209:etiology / Q000503:physiopathology; D016017:Odds Ratio; D016491:Peripheral Vascular Diseases / Q000150:complications / Q000000981:diagnostic imaging / Q000453:epidemiology* / Q000503:physiopathology; D015995:Prevalence; D018570:Risk Assessment; D012307:Risk Factors; D013030:Spain / Q000453:epidemiology; D014463:Ultrasonography