Long-term geometric stability of saphenous vein patched carotid endarterectomy

This study was designed to determine whether there is a generalized trend of progressive enlargement of the common and internal carotid bulbs after carotid endarterectomy (CEA) reconstruction with saphenous vein patches.

Twenty-nine autologous greater saphenous vein-patched CEAs performed between 1983 and 1994 were examined with five to nine sequential duplex scans each that included B-mode measurements of both the common carotid bulb (CCB) and internal carotid bulb (ICB) diameters. A total of 186 scans of each of the two segments were performed from 2 to 182 months after CEA (mean, 64 months). The time from the first to the last scan ranged from 30 to 120 months (mean, 76 months). Repeated measures analysis of variance was used as a means of testing the relationship of CCB and ICB diameters with time from CEA and with time from the first scan. Simple linear regression was used as a means of analyzing the variability of individual CCB and ICB diameters and pooled normalized diameters in both time frames.

The CCB diameters ranged from 8.4 to 18.5 mm (mean, 13.1 mm), and the ICB diameters ranged from 6.4 to 16.0 mm (mean, 11.2 mm). No significant relationship between both CCB and ICB diameters in the time from CEA or the time from the first scan (P =.643 to.913), for sex (P =.403 to.917), or for early and late post-CEA time of study onset (P =.135 to.773) was shown by means of repeated measures analysis. Low R(2) values (CCB mean, 0.17; ICB mean, 0.21) and non-significant P values for regression slope (CCB mean, 0.46; ICB mean, 0.54) were given by means of individual regression analysis. There was no correlation between individual regression coefficients and the mean diameters of the arteries. The mean change in CCB diameter was 0.023 mm/year (range, -0.37 to 0.30 mm/year), and the mean change in ICB diameter was -0.030 mm/year (range, -0.33 to 0.37 mm/year). Regression of normalized CCB and ICB diameters versus time gave R(2) values less than 0.02 and slopes not statistically significantly different from zero. The predicted 10-year average percent change in normalized diameters ranged from 0.8% to 3.3%.

In a 15-year period after CEA and a 10-year sequential B-mode scan study period, there was no evidence of significant enlargement of saphenous vein-patched CEAs. This is also true for CEAs in men and women and for subsets with larger and smaller CCB and ICB diameters and early and late scan onset times. Dilatation after saphenous vein patching is most likely a rare isolated event and not the result of generalized or frequent progressive enlargement.