THE INFLUENCE OF CAROTID SIPHON STENOSIS ON SHORT-TERM AND LONG-TERM OUTCOME AFTER CAROTID ENDARTERECTOMY

Purpose: This study was designed to determine whether the presence of ipsilateral carotid siphon stenosis influenced the risk of early and l ate stroke and death after carotid endarterectomy (CEA). Methods: The outcomes of patients with moderate (20% to 49%), severe (> 50%), and n o siphon stenosis were compared over a 16-year period from April 1976 to February 1992. Complete angiographic data were available in 393 car otid arteries. Results. Siphon stenosis was found ipsilateral to the C EA in 84 (21.4%) of the arteries. Most lesions were in the 20% to 49% diameter-reducing range (77.4%), with the remainder in the greater tha n 50% range (22.6%). There were no occlusions. The perioperative morta lity rate was nearly identical for the groups with and without siphon stenosis, 0.0% versus 0.6%, respectively (p = 0.99). Perioperative str oke morbidity rates (no stenosis, 2.3%; moderate stenosis, 3. 1%; > 50 % stenosis, 5.3%) were acceptable and were not statistically different (p > 0.38). Late ipsilateral stroke-free rates were similar in the gr oups with and without siphon stenosis. The 5- and 7-year stroke-free i ncidences were 88.5% and 83.4% versus 94.9% and 94.9%, respectively (p > 0.20) for the two groups. Long-term ipsilateral stroke-free rates w ere not significantly different in the subgroups with moderate (20% to 49%) and hemodynamically significant (> 50%) siphon stenosis. The 3- and 5-year ipsilateral stroke-free rates were 96.7% and 87.9% versus 9 4.6% and 94.6%, respectively (p = 0.69). Late death was more common in the group with siphon stenosis than it was in the group without sipho n stenosis, 23.8% versus 12.5% (p = 0.02). Heart disease was responsib le for most late deaths, 47% in both groups. Late stroke-related death s were infrequent: 1.3% in patients with and 0.0% in patients without siphon stenosis. Conclusions: Although carotid siphon stenosis seemed to be associated with a higher risk of late death, it did not alter th e short- and long-term stroke morbidity rates after carotid endarterec tomy significantly. We conclude that the presence of carotid siphon st enosis should not influence the decision to perform carotid endarterec tomy in patients with the appropriate indications.