Carotid endarterectomy for asymptomatic carotid stenosis: a ten-year experience with 120 procedures in a fellowship training program.

Performance of carotid endarterectomy for asymptomatic carotid stenosis has been restricted during recent years because of concern of reported complications in as high as 10-15% of patients, as well as limited long-term data on stroke protection. During the last 10 years, we have studied immediate and long-term results of carotid endarterectomy for asymptomatic disease in 120 patients. Operations were performed by a clinical vascular fellow with a staff surgeon in attendance in 113 (94%) cases with the remainder performed by the staff surgeon. Patients' mean age was 66 years; 82% were men. Risk factors included hypertension (56%), smoking (52%), coronary artery disease (32%), diabetes (24%), and hypercholesterolemia (6%). Arteriographic severity of stenoses was 80-99% in 74%, 60-79% in 22%, and 40-59% in 4% of cases. Postoperative complications included two transient neurological events (1.7%). No permanent strokes or deaths occurred. Using the life table method, cumulative stroke rate was 4.5% for ipsilateral events and 7.3% for contralateral events, confirming the high degree of stroke protection afforded by carotid endarterectomy in this population. Since these results were accomplished in a fellowship training program, we regard adequacy of this experience as the most influential factor in accomplishing this record. Surgeons who are unable to achieve comparable results should consider abandonment of the procedure or an extended period of additional training.

Carotid restenosis: long-term noninvasive follow-up after carotid endarterectomy.

Recurrent stenosis has not been a primary consideration in the selection of patients for carotid endarterectomy. We have studied the incidence of postoperative restenosis retrospectively in 265 patients following 310 carotid endarterectomies. Two hundred fourteen patients (248 endarterectomies) were examined at 6-12 month intervals using ocular pneumoplethysmography, spectral analysis, and B-mode imaging. The absolute incidence of recurrent carotid disease was 28% (69 of 248), with a 13% (33 of 248) incidence of hemodynamically significant restenosis and a 15% (36 of 248) incidence of hemodynamically insignificant disease. Life table analysis of the data projected a 32% incidence of hemodynamically significant restenosis after 7 years and a 40% incidence of hemodynamically insignificant recurrence. These data demonstrate a progressively increasing rate of restenosis. The incidence of ipsilateral neurologic events was 8% (24 of 310); 12 occurred in association with noninvasively evident recurrent disease (12 of 69, 17%), whereas 11 occurred in noninvasively determined normal arteries (11 of 179, 6%). Noninvasive follow-up was not available in 1 patient. Of the 12 events associated with recurrent disease, 5 occurred in association with hemodynamically significant restenosis (5 of 33, 15%), whereas 7 occurred in association with hemodynamically insignificant disease (7 of 36, 19%). Carotid endarterectomy is a durable operative procedure with 92% (286 of 310) of arteries remaining asymptomatic over the period of clinical follow-up. However, absolute and life table projections of the incidence of asymptomatic restenosis are high, and this factor should be considered in the selection of patients for carotid endarterectomy, particularly in the absence of lateralizing symptoms.

Poststenotic flow velocity changes as a function of stenosis geometry.

We used an in vitro pulsatile flow model to examine the velocity profile distal to a variable nonaxisymmetric stenosis. Using a continuous-wave Doppler velocimeter, the peak systolic frequency was determined distal to the stenosis and in planes parallel and perpendicular to the long axis of the stenosis. In both planes, an exponential regression best describes the relationship between peak systolic frequency and reduction in cross-sectional area. Regressions at each point of insonation diverged as a direct function of reduction in cross-sectional area and as an indirect function of distance from the stenosis. At each point of insonation, regressions representing the relationship in the mutually perpendicular planes diverged in direct proportion to reduction in cross-sectional area. Slopes were greater in parallel planes of insonation. These data demonstrate that two variables, distance and geometry, may influence the results of spectral analytic studies.

Interval breast cancer: a more aggressive subset of breast neoplasias.

It has been suggested that interval breast cancer (breast cancer found within 12 months of a negative screening examination) exhibits a more virulent behavior than those found by the screening clinic. To test this hypothesis, 120 new cases of breast cancer were retrospectively reviewed from our Breast Screening Center. These patients were divided into three groups--interval cancer cases, lesions found at initial screening, and lesions found at subsequent screening. Statistically significant differences seen in our interval cancer cases included a higher percentage of positive axillary nodes, higher overall mortality rate, and lower 6-year survival rate as calculated by left table analysis. The remaining data, although not statistically significant, demonstrate a parallel trend toward a more malignant behavior. It is concluded that interval breast cancers are more aggressive forms of breast neoplasias.