[The value of CW Doppler and Doppler-color-echocardiography in the mass screening for atherosclerotic carotid lesions].

BACKGROUND

The availability of non invasive ultrasound technologies for the diagnosis of extracranial carotid atherosclerotic disease allowed designing and applying mass screening programmes devoted to uncover and study unknown carotid stenosis in resident populations.

OBJECTIVE

To evaluate usefulness and correct application of Continuous Wave Doppler (CWD) and Color Coded Echo Flow Imaging (CCEF) examinations during different levels of the screening programme OPI (Obiettivo Prevenzione Ictus).

METHODS

Between January 29th 1990 and March 31st 1992 the screening programme OPI has been applied to 16.379 subjects of both sexes, aged 45 to 75, enrolled in a sanitary district of Lombardia. They underwent first level screening (anamnesis, physical examination, CWD of carotid arteries). 1.661 (10.1%) were suspected of harboring carotid lesions and invited to second level screening (physical examination, biohumoral sampling, CCEF): 1.587 attended. The results of CWD and CCEF examination of 3.174 carotid arteries are discussed.

RESULTS

An overall sensitivity and specificity of 63.6% and 66%, respectively, was found as CWD and CCEF were compared for lesions detectable by CWD (i.e. excluding kinkings and aneurysms). Of 1.815 carotid arteries classified as negative at CWD the absence of lesions was confirmed by CCEF for 1.450 (79.9%); CWD failed to reveal 146 (8%) stenosis < 50% and 52 (2.9%) severe lesions, of which only 5 (0.3%) could possibly undergo surgical treatment.

CONCLUSIONS

Despite low accuracy, CWD has proven to be useful for the purpose of a mass screening of carotid occlusive disease, that is selection of a contained group of subjects (10.1%), with increased risk for carotid stenosis, for further non invasive examination, with low cost (hardware cost: 1.430 lire per exam v/s 24.000 lire per exam for CCEF) and low risk of missing severe stenosis with possible surgical indication (0.3%).