Background: To estimate the influence of different kinds of angiographic internal carotid artery (ICA) stenosis assessment methods on clinical decision making on carotid surgery.
Method: One hundred angiographically proven ICA lesions in 65 patients (54 men, 11 women, mean age +/- SD, 64 +/- 8 years) were evaluated by simultaneous biplane angiography. The angiograms were analyzed using three kinds of linear diameter reduction methods [North American (NASCET), and European (ECST) carotid surgery trial method, common carotid artery method (CC)], and five area reduction methods reflecting more accurately the anatomical degree of stenosis [squared NASCET, ECST and CC (N2, E2, CC2), combined stenosis estimation of two projections (NASCET-bi, ECST-bi)].