BMC Public Health 2007, 7:348 http://www.biomedcentral.com/1471-2458/7/348 Randomised selection of the participants of the Primary Care Information Technology System (SIAP) ) E N I L E S A B ( Y D U T S R E V O - S S O R C y d u t s t r o h o C Phone contact (CALL CENTRE) Successful no yes Check inclusión and exclusion criteria Patient information Informed consent Fill out questionnaire: Medical history & physical examination AAI: • NORMAL AAI 0.9 to <1.4 • PATHOLOGIC AAI < 0.9 or > 1.4 Exclusion criteria: • In the COHORT study the patients of secondary prevention SEMESTRAL follow up (telephone call or personal interview): • Acute myocardial infarction • Angina • Ictus • Transitory ischaemic accident • Aneurysm of the abdominal aorta • Sudden death attributable to cardiovascular causes Another phone call (up to 5 more calls) Inclusion criteria: • Age >50 years • Obtain informed consent • Acceptation of visits protocol and fol ow up Exclusion criteria: • • IPnasttiietunctsionwailtihsetedrmpaintieanlntseoplasias o severe diseases in an •• aPPdaavttiiaeennncttssediwnipcthhaapcsaoecnittraateinddiocnatiinointiaftoinrgpethrfeorsmtuindgy AAI FFliogwurdeia1gram of the study Flow diagram of the study. The ankle-arm index (AAI) examination of the subjects will be carried out in the 24 healthcare centres participat- ing in the study by two healthcare professionals trained in the technique. The AAI will be performed in the two par- amaleolar arteries of both lower extremities, taking into consideration the lowest of four AAI determinations. If the result is < 0.9, the technique will be performed by the other professional. In cases in which the second profes- sional finds an AAI>= 0.9, the first will repeat the test and the latter value will be considered as the final result. AAI measurement will be performed by the standardised pro- cedure [6]. Patients with peripheral arterial disease will be referred to the general practitioner of the healthcare centre to which the patient is adscribed to follow the protocols of the cen- tre. If the AAI is lower than 0.5, the patient will be referred to the vascular surgeon of reference. Follow up (cohort study) After determination of the AAI the subject will enter in one of the cohorts (AAI>= 0.9: cohort without peripheral arterial disease; AAI < 0.9 cohort with peripheral arterial disease). The successive controls will be undertaken every 6 months after the last visit, by telephone interview. The appearance Page 4 of 7 (page number not for citation purposes)