Prognosis of carotid siphon stenosis.

Prognosis of Carotid Siphon Stenosis To the Editor: In their interesting paper, Wechsler et al confirmed that siphon stenosis carries a poor prognosis for life, as one-third of their patients were dead at the end of a 51-month follow-up. In a previous study involving 15 patients with siphon stenosis of > 30% (without proximal atherosclerosis of equal or greater severity), we also found a high mortality. Our series now has 22 patients (12 men, 10 women; mean age 60 years) who have been followed for an average of 40.4 months. The mortality rate is high (1 stroke death, 6 cardiac deaths) and is similar to the previously reported rates, but ipsilateral stroke is higher (Table 1). One-third of the patients could not resume prior activity. There is a striking difference between patients with associated proximal internal carotid artery atherosclerosis and those without; over 80% of all delayed events occurred in the former group. These findings suggest that 1) siphon stenosis in the context of associated proximal atherosclerosis is a marker of severe atherosclerotic disease and bears a very poor prognosis, and 2) isolated siphon stenosis may correspond to another type of atherosclerotic disease, although risk factors do not seem to differ. It is not known at the present time how often isolated siphon stenosis merits the term "atherosclerotic" in the absence of pathological studies.