Common Carotid Bulb Research Articles

Abstract EP49: 6-minute Walk Test Distance And Atherosclerosis, Expressed As Carotid Intima-media Thickness, In Older Korean Adults

Background: Carotid intima-media thickness (cIMT) is a well-known marker of atherosclerosis and future cardiovascular events such as myocardial infarction. The 6-minute walk test (6MWT) is a widely used method for evaluating aerobic fitness and functional exercise capacity. However, no studies have assessed the relationship between 6MWT distance and cIMT in older adults. Therefore, this study aimed to examine the association between aerobic fitness expressed as the 6MWT distance and cIMT in older Korean adults. Methods: We retrospectively reviewed raw data of the 2014-2015 Korean Institute of Sports Science Fitness Standards, a national fitness measurement project in Korea. Participants older than 65 years and who underwent 6MWT and cIMT measurements were included in the study. The 6MWT was performed, and the total distance that the participants covered in 6 min was measured. The cIMT was defined as the distance between the lumen-intima and the media-adventitia interfaces. The cIMT was measured at the proximal 1 cm of the right common carotid bulb. A high-resolution ultrasound device with a frequency of ≥11.4 MHz was used for cIMT measurement. We adjusted the data for multiple confounding factors. Statistical analyses were performed using generalized linear regression analysis. Results: Overall, 608 participants were included (male, n=302 [49.67%]; female, n=306 [50.32%]). The mean participant age was 70.99±4.22 years (male 71.48±4.40 years, female 70.50±3.98 years). The mean cIMT was 0.74±0.18 mm (male 0.78±0.19 mm, female 0.70±0.16 mm). The mean 6MWT distance was 479.15±92.82 m (male 499.96±85.88 m, female 458.60±94.94 m). After multivariable adjustment, the highest 6MWT distance tertile was inversely associated with cIMT (β [95% confidence interval (CI)]: -0.042 [-0.080, -0.005]; p=0.027) versus the lower tertiles. In the subgroup analysis, the male group did not show a significant association with cIMT, while the highest 6MWT distance tertile in the female group showed a significant inverse association with cIMT ((β [95% CI]: -0.049 [-0.098, -0.001]; p=0.049). Conclusion: Our results suggest that there is an inverse relationship between 6MWT distance and atherosclerosis, expressed as cIMT, in older Korean adults.

Carotid artery remodelling in relation to body fat distribution, inflammation and sustained weight loss in obesity

Obesity is known to be associated with carotid artery remodelling, but less is known about how body fat distribution, inflammation and weight loss may affect this relation. Ultrasonography, dual-energy X-ray absorptiometry and computed tomography were performed to evaluate carotid artery intima-media thickness (IMT), body composition and fat distribution, respectively. Participants were divided into three matched study groups (n = 44 per group): obese patients with sustained weight loss 10 years after bariatric surgery [surgery group, body mass index (BMI) 31.5 kg m(-2)]; obese patients who maintained stable weight during the same time period (obese group, BMI 42.5 kg m(-2)); and normal weight subjects (lean group, BMI 24.4 kg m(-2)). Patients in the surgery group, compared with those in the obese group, had slightly lower common carotid artery (CCA) IMT (0.75 ± 0.18 vs. 0.78 ± 0.17 mm) and common carotid bulb (CCB) IMT (0.92 ± 0.32 vs. 0.97 ± 0.32 mm); however, these differences were not statistically significant. Lean individuals, compared with those in the surgery group, had significantly lower CCA and CCB IMT values (P < 0.001). In forward stepwise multiple regression analyses including all subjects (n = 132), CCA IMT was predicted mainly by visceral adipose tissue, but was also related to blood pressure and levels of triglycerides and high-sensitivity C-reactive protein. Carotid lumen diameter was primarily influenced by lean body mass. Visceral adiposity was the main determinant of premature carotid artery atherosclerosis, possibly through elevated blood pressure, dyslipidaemia and inflammation. Lean body mass predicted carotid artery lumen diameter. Obese patients with long-term sustained weight loss did not have thinner carotid artery walls compared with their weight-stable obese counterparts.

Long-term geometric stability of saphenous vein patched carotid endarterectomy

Purpose: 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. Methods: 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. Results: 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 R2 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 R2 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%. Conclusion: 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. (J Vasc Surg 2002;35:131-6.)

Restenosis After Carotid Endarterectomy in Patients with Paired Vein and Dacron Patch Reconstruction

This is an analysis of restenosis after bilateral carotid endarterectomy (CEA) with saphenous vein patch reconstruction on one side and Dacron patch reconstruction on the other. The possibility that differences in reconstruction geometry between vein and Dacron patched sides effected restenosis outcomes was evaluated as was the value of serial common carotid wall thickness measurements in predicting restenosis. Between 1990 and 1997, 33 bilateral CEA were performed within one year on 22 men and 11 women using a greater saphenous vein patch on one side and a knitted Dacron patch on the other. Interoperative post-CEA geometry was measured. Follow-up was by duplex scans that included wall thickness measurements in the endarterectomized common carotid bulb. Over a mean follow-up of 43 months 10 (30%) Dacron patched and one (3%) vein patched CEA developed > or = 25% restenosis (p = 0.001), seven (21%) Dacron patched and no vein patched CEA developed > or = 50% restenosis (p = 0.01) and four (12%) Dacron patched and no vein patched CEA developed > or = 70% restenosis (p = 0.11). The Kaplan-Meier cumulative > or = 25% restenosis rates for Dacron and vein patched CEA were 22% and 0% at 2 years and 41% and 5% at 5 years respectively (p = 0.002). The cumulative > or = 50% restenosis rates for Dacron and vein patched CEA were 16% and 0% at 2 years and 34% and 0% at 5 years respectively (p = 0.003). The cumulative > or = 70% restenosis rates for Dacron and vein patched CEA were 8% and 0% at 2 years and 20% and 0% at 5 years respectively (p = 0.02). For both patients with and without recurrent stenosis the mean within patient between sides differences of the diameters of the internal carotid, internal carotid bulb, common carotid bulb, and common carotid arteries and the lengths of the internal carotid and total patch segments were not significantly different and all were less than 5%. Common carotid bulb wall thickness measured at the time of identification of the nine unilateral Dacron patched CEA restenosis was 1.5 +/-0.5 mm compared to 1.4 +/-0.4 mm (m +/-1 SD) for the contralateral vein patched CEA (p = 0.45 by paired t test). Dacron patched CEA have a significantly higher incidence of mild, moderate and severe restenosis than do saphenous vein patched CEA independent of systemic risk factors. The within patient equality of Dacron and vein patched carotid reconstruction geometry in patients with unilateral restenosis indicates that patch material is the major local risk factor, not adverse hemodynamics produced by variance in geometry. Common carotid bulb wall thickness measurements after CEA are not predictors or indicators of recurrent stenosis.

Geometric dimension changes with carotid endarterectomy reconstruction.

The geometry of carotid endarterectomy (CEA) reconstruction is a major determinant of carotid bifurcation hemodynamics that, in turn, may play a significant role in the likelihood of early postoperative thrombosis and early and late restenosis. The purpose of this study was to measure the geometry of various types of CEA reconstructions. Six carotid artery diameters and lengths were measured during surgery, before and after CEA. Three reconstruction methods were used in 562 CEA procedures: a greater saphenous vein patch in 389, a synthetic patch in 157, and primary closure in 16. Veins 6 mm or more in distended diameter were trimmed before use as a patch. Synthetic patches were 8 to 11 mm in width. Patch reconstruction was used when the length of the arteriotomy required to obtain a complete distal endarterectomy end point extended beyond the internal carotid artery bulb. Saphenous vein patches were used when it was available and adequate. Neither gender nor internal carotid artery diameter was used as a criteria for the selection of the reconstruction method. Before endarterectomy, the 302 male carotid arteries had 7% to 15% greater linear dimensions than the 260 female arteries (p < 0.001). Both vein and synthetic patch reconstruction produced up to 16% changes in linear dimensions except for almost doubling of the length of the internal carotid bulb. Patching made the elliptical common carotid bulb significantly more round, but the maximum diameter of curvature of the carotid bulb remained unchanged. Primary closure slightly decreased the diameter of the internal carotid bulb. CEA patch reconstruction has two major effects on carotid geometry: an increase in internal carotid bulb length and a more round common carotid bulb. The former allows for a gradual transition from the terminal common carotid bulb to the uniform diameter more distal internal carotid artery. It also separates the two major causes of disturbed flow: the bifurcation and the step-down in internal carotid artery diameter. Primary closure has minimal effect on preoperative geometry.

Wall thickness after carotid endarterectomy in patients with paired vein and Dacron patch reconstruction.

This is an analysis of early postcarotid endarterectomy (CEA) wall thickness in patients who have undergone bilateral operations with vein and Dacron patch reconstructions. In the past 5 years 23 patients had staged bilateral CEA within 2 months with an autologous greater saphenous vein patch on one side and a knitted Dacron patch on the other. Duplex scans with adequate B-mode resolution to measure common carotid bulb total wall thickness were performed in all 23 patients during the first post-CEA year and in 12 patients in the post-CEA second year. There were no hemodynamically detectable restenoses by Doppler velocity criteria. All peak systolic velocities were < or = 110 cm/sec. In the first post-CEA year the total wall thickness of the 23 vein patch CEA was 1.7 +/- 1.0 mm (mean +/- 1 SD; range, 0.6 to 5.5 mm), and the total wall thickness of the 22 Dacron patch CEA was 1.7 +/- 1.1 mm (range, 0.6 to 6.1 mm, p = 0.93). In the second post-CEA year wall thickness was 2.1 +/- 1.8 mm (range, 0.6 to 5.8 mm) in the vein patch arteries and 2.0 +/- 1.5 mm (range, 0.6 to 5.4 mm, p = 0.91) in the Dacron patch arteries. Although wall thickness of both vein and Dacron patch CEA varied widely between patients, the within-patient absolute difference between the two sides was quite small, 0.1 +/- 0.3 mm in the first year and 0.2 +/- 0.5 mm in the second. With a 5% chance of a type I statistical error (alpha = 0.05) to detect a 0.5 mm difference in wall thickness between Dacron and vein patch CEA, the power of the paired t test is > 0.999, and the probability of a type II error, beta, is < 0.001 (power = 1-beta) in the first year. In the second year beta = 0.34. Wall thickness was bilaterally eccentric in 17 patients. The minimum thickness was in the patch wall, and the maximum was in the opposite endarterectomized wall. It was circumferentially uniform in five patients with < 1 mm wall thickness. The single patient with significant bilaterally concentric wall thickness in the first year was the only one who had a marked increase in wall thickness between the first and second years. Wall thickness > 2 mm was associated with continued smoking (p = 0.03). Post-CEA wall thickening is highly patient-dependent but is patch material-independent. Knitted Dacron and saphenous vein patch reconstructed carotid arteries develop almost identical wall thickness in a given patient in the first 2 years after endarterectomy. These results support the use of knitted Dacron as an acceptable alternative to greater saphenous for a CEA patch.

Early and late geometric changes after carotid endarterectomy patch reconstruction

This study examines the degree and location of vessel wall geometric changes after carotid endarterectomy—vein patch reconstruction. The external diameters of the proximal common carotid, common carotid bulb, and internal carotid arteries were measured during operation with a caliper after 349 carotid endarterectomies. There were 309 saphenous vein reconstructions, 31 synthetic patch reconstructions, and 9 primary closures. One or more B-mode ultrasound studies with cross-sectional views for common and internal carotid cursor measurements were performed from 3 months to 5 years after operation. The intraoperative-to-postoperative common carotid diameters were unchanged for the three types of reconstructions. The internal carotid diameters increased 20% to 30% for both the vein and synthetic patched arteries. This dilation was present at 3 and 6 months and progressed slightly over 5 years. Wall thickening ≥1 mm was present in 62% of the carotid endarterectomies, with concentric stenosis in 3% and eccentric stenosis in 59%. Eccentric stenosis was present at 3 to 6 months, located on the endarterectomized posterior-medial wall of the common and internal carotid arteries, was always less than 50%, and changed very little over 5 years. No aneurysms or internal carotid occlusions were identified. Carotid endarterectomy—vein patch reconstruction results in early, mild, nonaneurysimal dilation of the internal carotid patched segment, frequent mild eccentric restenosis, and rare hemodynamically significant concentric restenosis.