Randomized clinical trial of remote ischaemic preconditioning versus no preconditioning in the prevention of perioperative myocardial infarction during open surgery for ruptured abdominal aortic aneurysm.

BACKGROUND: Remote ischaemic preconditioning (RIPC) has been suggested as a means of protecting vital organs from reperfusion injury during major vascular surgery. This study was designed to determine whether RIPC could reduce the incidence of perioperative myocardial infarction (MI) during open surgery for ruptured abdominal aortic aneurysm (AAA). Secondary aims were to see if RIPC could reduce 30-day mortality, multiple organ failure, acute intestinal ischaemia, acute kidney injury and ischaemic stroke. METHODS: This randomized, non-blinded clinical trial was undertaken at three vascular surgery centres in Denmark. Patients who had open surgery for ruptured AAA were randomized to intervention with RIPC or control in a 1 : 1 ratio. Postoperative complications and deaths were registered, and ECG and blood samples were obtained daily during the hospital stay. RESULTS: Of 200 patients randomized, 142 (72 RIPC, 70 controls) were included. There was no difference in rates of perioperative MI between the RIPC and control groups (36 versus 43 per cent respectively), or in rates of organ failure. However, in the per-protocol analysis 30-day mortality was significantly reduced in the RIPC group (odds ratio 0·46, 95 per cent c.i. 0·22 to 0·99; P = 0·048). CONCLUSION: RIPC did not reduce the incidence of perioperative MI in patients undergoing open surgery for ruptured AAA. Registration number: NCT00883363 ( http://www.clinicaltrials.gov).

Validity of Peripheral Arterial Disease Diagnoses in the Danish National Patient Registry.

OBJECTIVES/BACKGROUND: The objective was to validate the diagnoses of peripheral arterial disease (PAD) in the legs, obtained from national registers in Denmark. METHODS: In total, 1435 registered cases of PAD were identified in the Danish National Patient Registry among 57,053 middle aged participants from the Danish Diet, Cancer and Health cohort study. Validation was performed by reviewing all medical records using pre-specified criteria for a diagnosis of PAD. RESULTS: The overall positive predictive value (PPV) of PAD diagnoses was 69.4% [95% confidence interval (CI) 67.0-71.7]. The PPV of diagnoses given in departments of vascular surgery was significantly higher than diagnoses given in other departments: 71.9% (95% CI 69.2-74.4) versus 58.3% (95% CI 52.2-64.2), respectively. In a sub-study, 141 potential cases of PAD also registered in the Danish National Vascular Registry were evaluated, and a PPV of 87.9% (95% CI 81.4-92.4) was found for these diagnoses. CONCLUSION: More than 30% of the diagnoses of PAD notified in the Danish National Patient Registry were not valid, stressing the importance of validation when using register information for research purposes. In contrast, diagnoses obtained from the Danish National Vascular Registry had a high validity ready for use without further validation.

Real-time spatial compound imaging improves reproducibility in the evaluation of atherosclerotic carotid plaques.

Compound imaging has the ability of reducing speckle and clutter artifacts demonstrated in in vitro studies compared to conventional, single-angle imaging. We investigated intra- and interobserver agreement of 38 outlines of carotid artery plaque images acquired by these techniques, by measuring the overlapping area after repeated outlines. In general, both techniques showed good agreement. When considering the images with poorest overlap, compound imaging had a significant advantage over conventional imaging regarding both intra- and interobserver agreement. The interobserver variation for the overlapping area after two outlines was 20% for conventional technique and 10% for compound. The interobserver variation of the gray scale median value (GSM) for conventional technique ranged from -32 to +20 and from -6 to +6 for compound. Likewise, the coefficient of repeatability for the GSM value was 13 for conventional imaging and three for compound imaging, and interobserver variation for the GSM value for the overlapping area was 34% and 9% for conventional and compound technique. In conclusion, compound imaging improves intra- and interobserver agreement and reduces interobserver variation in the GSM value in a clinical setting.

Ultrasonic echolucent carotid plaques predict future strokes.

BACKGROUND: We tested prospectively the hypothesis that stroke development can be predicted by echolucency of carotid atherosclerotic plaques in previously symptomatic and asymptomatic patients. METHODS AND RESULTS: We followed incidence of ipsilateral ischemic strokes for 4.4 years in 111 asymptomatic and 135 symptomatic patients with >/=50% relevant carotid artery stenosis. At inclusion, echogenicity of carotid plaques and degree of stenosis were evaluated with high-resolution B-mode ultrasound with computer-assisted image processing and Doppler ultrasound, respectively. We observed 44 ipsilateral ischemic strokes. In symptomatic patients, relative risk of ipsilateral ischemic stroke for echolucent versus echorich plaques was 3.1 (95% CI, 1.3 to 7.3), whereas for 80% to 99% versus 50% to 79% stenosis, the relative risk was 1.4 (95% CI, 0.7 to 3.0). Relative to symptomatic patients with echorich 50% to 79% stenotic plaques, those with echorich 80% to 99% stenotic plaques, echolucent 50% to 79% stenotic plaques, and echolucent 80% to 99% stenotic plaques had relative risks of ipsilateral ischemic strokes of 3.1 (95%CI, 0.7 to 14), 4.2 (95% CI, 1.2 to 15), and 7.9 (95% CI, 2.1 to 30), equivalent to absolute risk increases of 11%, 18%, and 28%. This was not observed in previously asymptomatic patients. CONCLUSIONS: Echolucent plaques causing >/=50% diameter stenosis by Doppler ultrasound are associated with risk of future stroke in symptomatic but not asymptomatic individuals. This suggests that measurement of echolucency, together with degree of stenosis, may improve selection of patients for carotid endarterectomy.

Spiral computed tomographic imaging related to computerized ultrasonographic images of carotid plaque morphology and histology.

OBJECTIVE: Echolucency of carotid atherosclerotic plaques, as evaluated by computerized B-mode ultrasonographic images, has been associated with an increased incidence of brain infarcts on cerebral computed tomographic scans. We tested the hypotheses that characterization of carotid plaques on spiral computed tomographic images correlates with that on computerized B-mode ultrasonographic images and that spiral computed tomographic imaging predicts the histomorphometric plaque content. METHODS: The study included 38 patients with neurologic symptoms and at least 50% stenosis of the ipsilateral carotid artery. High-resolution B-mode ultrasonographic images and spiral computed tomographic images of carotid plaques were computer processed to yield a quantitative measure, the gray scale level of the plaque. RESULTS: The mean Hounsfield value for spiral computed tomographic images correlated with the gray scale median for B-mode ultrasonographic images (univariate linear regression analysis: r = 0.45; P = .01) and the histologic content of calcification in the plaque (r = 0.34; P = .04) but not with lipid, hemorrhage, or fibrous tissue in the plaque. CONCLUSIONS: Spiral computed tomographic imaging seems to correlate with B-mode ultrasonographic imaging for showing plaque characteristics. Spiral computed tomographic attenuation was also correlated with the amount of calcification noted on histologic examination but not with lipid and hemorrhage, the components thought to characterize vulnerable, rupture-prone plaques.

Increased acute phase reactants are associated with levels of lipoproteins and increased carotid plaque volume.

OBJECTIVES: to test the hypotheses that increased acute phase reactants predict elevated levels of lipoproteins and increased plaque volume as well as echolucency of carotid plaques. MATERIALS AND METHODS: the study included 258 patients with >or =50% carotid artery stenosis. Acute phase reactants (orosomucoid, C-reactive protein (CRP)) were measured in the fasting state, and ultracentrifugated lipoproteins before and after a standardised fat load test. Echogenicity of carotid plaques was detected using high-resolution B-mode ultrasound and computer-assisted image processing. A subgroup of 81 patients underwent carotid endarterectomy. RESULTS: on linear regression analysis orosomucoid levels were positively associated with fasting and postprandial levels of all triglyceride-rich lipoproteins, and negatively associated with HDL cholesterol (p -values <0.0001); results for CRP were less pronounced. Orosomucoid and CRP both predicted the presence of an increased carotid plaque volume on univariate analysis (p =0.01 and p =0.02). Finally, orosomucoid was negatively associated with echolucency of carotid plaques ( p =0.05). CONCLUSIONS: elevated levels of acute phase reactants are strongly associated with elevated levels of triglyceride-rich lipoproteins, increased plaque volume, and borderline significantly associated with echolucency of carotid plaques. Elevated acute phase reactants possibly predict severity of atherosclerosis, and presence of lipid-rich, rupture-prone plaques.

Angiotensinogen mutations and risk for ischemic heart disease, myocardial infarction, and ischemic cerebrovascular disease. Six case-control studies from the Copenhagen City Heart Study.

BACKGROUND: The M235T and T174M angiotensinogen mutations have been linked to increased risk for ischemic heart and cerebrovascular disease. OBJECTIVE: To determine whether angiotensinogen mutations are associated with ischemic heart disease, myocardial infarction, and ischemic cerebrovascular disease. DESIGN: Six case-control studies from the Copenhagen City Heart Study. SETTING: Copenhagen, Denmark. PARTICIPANTS: Participants in the Copenhagen City Heart Study and patients from the same hospital with ischemic heart disease (n = 866 and n = 943, respectively), myocardial infarction (n = 519 and n = 493, respectively), or ischemic cerebrovascular disease (n = 489 and n = 434, respectively) and 7975 controls without these conditions. MEASUREMENTS: Genotypes for the M235T and T174M angiotensinogen mutations were compared between controls and Copenhagen City Heart Study participants with ischemic heart disease, myocardial infarction, and cerebrovascular disease (studies 1a, 1b, and 1c) and patients from Copenhagen University Hospital with the same conditions (studies 2a, 2b, and 2c). RESULTS: Relative allele frequencies of 235T and 174M in the general population were 0.41 and 0.12, respectively. Genotype was not associated with increased risk for ischemic heart or ischemic cerebrovascular disease in studies of either mutation alone or combined in women or men. Among compound heterozygotes (235MT /174TM ), women in case-control study 2a had decreased risk for ischemic heart disease in age-adjusted analysis; however, this decreased risk was not seen in multifactorial-adjusted or matched analyses, in men, or in case-control study 1a. Among double homozygotes (235TT /174MM ), women in case-control study 2b had increased risk for myocardial infarction in matched analysis; however, this increased risk was not seen in age- or multifactorial-adjusted analyses, in men, or in case-control study 1b. Among single homozygotes (235TT /174TT ), men in case-control study 2b had increased risk for myocardial infarction in multifactorial-adjusted and matched analyses. This risk was not present in age-adjusted analysis, in women, or in case-control study 1b. In addition, male single homozygotes had decreased risk for ischemic cerebrovascular disease in case-control study 2c in age- and multifactorial-adjusted analyses, but this finding was not seen in matched analysis, in women, or in case-control study 1c. CONCLUSIONS: In six large case-control studies, the M235T and T174M angiotensinogen mutations were not consistently associated with increased (or decreased) risk for ischemic heart disease, myocardial infarction, or ischemic cerebrovascular disease. Statistically significant associations may represent chance findings rather than real phenomena.

APOE genotype predicts AD and other dementia but not ischemic cerebrovascular disease.

BACKGROUND: The APOE polymorphism is an important modulator of plasma lipoproteins and a risk factor for AD. The hypothesis that APOE genotype, through its effect on lipoproteins, is a common risk factor for ischemic cerebrovascular disease (ICVD), AD, and other dementia (OD) was tested. METHODS: The authors genotyped 9241 individuals from the general population, 452 patients with ICVD and > or = 50% stenosis of the carotid arteries, and 75 patients with ICVD before the age of 50 years. Among the individuals from the general population, 211 had ICVD, 26 had AD, and 28 had OD. RESULTS: The APOE polymorphism was not associated with ICVD in any of the three patient groups. In contrast, the epsilon43 and epsilon44 genotypes were associated with 3- and 10-fold risks of AD (95% CI = 1.4 to 8.0 and 2.5 to 41.0), and the epsilon43 genotype was also associated with a 2.5-fold risk of OD (95% CI = 1.1 to 5.5). These increases in risk were not abolished by adjustment for lipids and lipoproteins. The fraction of AD that could be attributed to the epsilon43 and epsilon44 genotypes was 37 and 20% in the general population, whereas the fraction of OD that could be attributed to the epsilon43 genotype was 26%. CONCLUSION: The APOE polymorphism is a risk factor for AD and OD independent of lipid and lipoprotein levels but does not affect the risk of ICVD.

Subtle brain damage cannot be detected by measuring neuron-specific enolase and S-100beta protein after carotid endarterectomy.

OBJECTIVE: To assess whether subtle brain damage after carotid endarterectomy could be detected using serum levels of neuron-specific enolase (NSE) or S-100beta protein. DESIGN: Prospective noninterventional study. SETTING: University hospital. PARTICIPANTS: Twenty-two patients undergoing carotid endarterectomy and 16 patients undergoing repair of abdominal aortic aneurysm. INTERVENTIONS: Serum levels of NSE and S-100beta protein were measured in all patients before surgery and postoperatively at 12, 24, 36, and 48 hours. In patients undergoing carotid endarterectomy, neuropsychologic testing was performed before surgery and postoperatively at discharge from the hospital and after 3 months using a neuropsychologic test battery. MEASUREMENTS AND MAIN RESULTS: Compared with abdominal aortic surgery patients, the preoperative serum concentration of NSE was significantly higher in carotid artery surgery patients. Postoperatively, the NSE serum level decreased significantly after uncomplicated carotid artery surgery, and the level was then similar to that in the aortic surgery patients. Before operation, the S-100beta protein levels were similar in the two groups, but a significant increase was seen in aortic surgery patients postoperatively. Neuropsychologic testing after uncomplicated carotid artery surgery revealed cognitive dysfunction in 2 of 20 (10%) of the patients after 5 days and 3 of 16 (19%) of the patients after 3 months. There was no correlation between the change in cognitive function and the changes in blood levels of either NSE or S-100 protein. CONCLUSIONS: Subtle brain damage after carotid artery surgery could not be detected by measuring blood levels of NSE and S-100beta protein. The NSE level was significantly higher before carotid artery surgery and decreased postoperatively to the level observed in aortic surgery.

Ultrasound and lipoproteins as predictors of lipid-rich, rupture-prone plaques in the carotid artery.

The aim of this review is to summarize present knowledge of the ultrasonic detection and determinants of carotid atherosclerosis with lipid-rich cores and to review the evidence that these measures of plaque type may predict cerebral events. With the use of high-resolution ultrasound B-mode imaging, carotid plaques evaluated as only weakly reflecting the ultrasound beam (echolucent) have been associated with a higher risk of neurological events than are plaques reflecting the ultrasound signal strongly (echorich). Histologically, these echolucent plaques have a higher content of lipid and hemorrhage than do echorich plaques, which contain more calcification and fibrous tissue. Findings in the coronary arteries indicate that a lipid-rich plaque with a thin, fibrous cap is more vulnerable, is more prone to rupture, and cause symptoms compared with fibrous plaques. A search for determinants in the blood for these vulnerable plaques suggests that low density lipoprotein (LDL) cholesterol is the best lipid predictor for the extent of atherosclerosis, whereas triglyceride-rich lipoproteins in particular seem to predict an echolucent plaque. Lowering of LDL cholesterol and triglyceride-rich lipoproteins in plasma is associated with reduced progression of coronary atherosclerosis and coronary events. LDL cholesterol reduction is also associated with a reduced stroke rate. These improvements in the prognosis are thought to be the result of a reduction in the lipid content of the plaques, making them more stable and resistant to rupture rather than an actual reduction in plaque volume and degree of stenosis. In conclusion, it appears that ultrasound B-mode imaging as well as lipoproteins presumably may predict dangerous and rupture-prone, lipid-rich plaques in the carotid arteries, thereby being potential diagnostic tools in the prevention of neurological events.

Coronary atherosclerosis: determinants of plaque rupture.

The most important mechanism responsible for the sudden and unpredictable onset of acute coronary syndromes is coronary plaque rupture with thrombosis and vasospasm superimposed. The risk of plaque rupture depends on plaque type (composition) rather than plaque size (volume); most ruptures occur in plaques containing a soft, lipid-rich core that is covered by a thin and inflamed cap of fibrous tissue. Compared with intact caps, the ruptured ones usually are thinner and contain less collagen (responsible for tensile strength), fewer smooth muscle cells (smc; collagen synthesizing cells), and many more macrophages (collagen degrading cells). Therefore, major determinants of plaque vulnerability and rupture are progressive lipid accumulation (core formation) and cap weakening due to ongoing inflammation with collagen degradation (macrophage-related) and impaired healing and repair (smc-related). These intrinsic plaque changes predispose plaques to rupture whereas extrinsic forces imposed on plaques, such as biomechanical and haemodynamic stresses, may determine the actual time of rupture by precipitating or 'triggering' it. Luckily, recent research in patients with coronary artery disease indicates that both plaque vulnerability and rupture triggers may be modified beneficially by treatment.

Echo-lucency of computerized ultrasound images of carotid atherosclerotic plaques are associated with increased levels of triglyceride-rich lipoproteins as well as increased plaque lipid content.

BACKGROUND: Echo-lucency of carotid atherosclerotic plaques on computerized ultrasound B-mode images has been associated with a high incidence of brain infarcts as evaluated on CT scans. We tested the hypotheses that triglyceride-rich lipoproteins in the fasting and postprandial state predict carotid plaque echo-lucency and that echo-lucency predicts a high plaque lipid content. METHODS AND RESULTS: The study included 137 patients with neurological symptoms and > or = 50% stenosis of the relevant carotid artery. High-resolution B-mode ultrasound images of carotid plaques were computer processed to yield a measure of echogenicity (gray-scale level). Lipoproteins were measured before and hourly for 4 hours after a standardized fatty meal. A subgroup of 58 patients underwent endarterectomy. On linear regression analysis, echo-lucency (low gray-scale level) was associated with elevated levels of fasting and postprandial plasma triglycerides (P=.0002 and P=.002), IDL cholesterol (P=.0009 and P=.006), and VLDL/chylomicron remnant cholesterol (P=.0003 and P=.0004) and triglycerides (P=.0003 and P=.003), the area under the plasma triglyceride curve 0 to 4 hours after a fatty meal (P=.001), and body mass index (P=.0001). On ANCOVA, body mass index, fasting IDL cholesterol, and fasting plasma triglycerides were independent predictors of echo-lucency. Echo-lucency was associated with increased relative plaque lipid content (P=.02). CONCLUSIONS: Increased plasma levels of triglyceride-rich lipoproteins predict echo-lucency of carotid plaques, which is associated with increased plaque lipid content. Because echo-lucency has been associated with a high incidence of brain infarcts on CT scans, triglyceride-rich lipoproteins may predict a plaque type particularly vulnerable to rupture.

Quantitative analysis of ultrasound B-mode images of carotid atherosclerotic plaque: correlation with visual classification and histological examination.

This paper presents a quantitative comparison of three types of information available for 52 patients scheduled for carotid endarterectomy: subjective classification of the ultrasound images obtained during scanning before operation, first-and second-order statistical features extracted from regions of the plaque in still ultrasound images from three orthogonal scan planes and finally a histological analysis of the surgically removed plaque. The quantitative comparison was made with the linear model and with separation of the available data into training and test sets. The comparison of subjective classification with features from still ultrasound images revealed an overall agreement of 60% for classification of echogenicity and 70% for classification of structure. Comparison of the histologically determined relative volume of soft materials with features from the still images revealed a correlation coefficient of r = -0.42(p = 0.002). for mean echogenicity of the plaque region. The best performing feature was of second order and denoted Contrast (r = -0.5). Though significant, the latter correlation is probably not strong enough to be useful for clinical prediction of relative volume of soft materials for individual patients. Reasons for this is discussed in the paper, together with suggestions for improvements.

ACE gene polymorphism as a risk factor for ischemic cerebrovascular disease.

BACKGROUND: Researchers have suggested that the deletional allele of the ACE (angiotensin-converting enzyme) gene insertion-deletion polymorphism is a potent risk factor for myocardial infarction. This association could not be confirmed in the Copenhagen City Heart Study, in which 10,150 persons were studied. The ACE gene polymorphism has also recently been suggested as a potent risk factor for ischemic cerebrovascular disease. OBJECTIVE: To investigate the association between ACE gene polymorphism and ischemic cerebrovascular disease. DESIGN: Two case-referent studies and a cross-sectional study. SETTING: University hospital in Copenhagen, Denmark. PARTICIPANTS: Case-referent study 1: 35 women and 38 men who developed ischemic cerebrovascular disease before 50 years of age compared with 1454 women and 1737 men from a general population sample. Case-referent study 2: 82 women and 137 men with ischemic cerebrovascular disease and carotid stenosis greater than 40% compared with 4273 women and 3091 men from the general population sample. Cross-sectional study of the general population sample: 67 women and 93 men with ischemic cerebrovascular disease compared with 4077 women and 3156 men without such disease. MEASUREMENTS: Genotype; age; body mass index; smoking habits; levels of lipids, lipoproteins, apolipoproteins, and fibrinogen; and diagnosis of hypertension, diabetes mellitus, and ischemic cerebrovascular disease. RESULTS: Odds ratios for ischemic cerebrovascular disease by ACE genotype classes were not significantly different from 1.0 in women or men in any of the three studies, separately or combined. In a logistic regression analysis that controlled for age and conventional cardiovascular risk factors, odds ratios in either sex still did not significantly differ from 1.0 in any study, separately or combined. CONCLUSION: In two case-referent studies, a cross-sectional study, and the three studies combined, no statistically significant difference was found in the development of ischemic cerebrovascular disease between genotype classes of the ACE gene polymorphism in women or men.

In vivo transfer of lipoprotein(a) into human atherosclerotic carotid arterial intima.

The aim of this study was to compare the atherogenic potential of lipoprotein(a) [Lp(a)] and LDL by measuring the intimal clearance of these two plasma lipoproteins in the atherosclerotic intima of the human carotid artery in vivo. Autologous 131I-Lp(a) and 125I-LDL were mixed and reinjected intravenously 3 hours before elective surgical removal of the arterial intima in four patients. The intimal clearance of Lp(a) and LDL was 229+/-48 and 405+/-127 nL/cm2 per hour, respectively (paired t test; P=.12). The mass accumulation of Lp(a) (114+/-32 ng/cm2 per hour) was on average one 15th that of LDL (paired t test; P=.06), mainly reflecting a low plasma concentration of Lp(a) compared with LDL in the human subjects studied. In accordance with our previous observation in rabbits, there was a positive association between the intimal clearance of LDL and that of Lp(a) (r=.97, P=.03). Accordingly, high plasma levels of Lp(a) may share with LDL the potential for causing lipid accumulation in the arterial intima in humans.

Lipid-rich carotid artery plaques appear echolucent on ultrasound B-mode images and may be associated with intraplaque haemorrhage.

OBJECTIVE: To relate the histological composition of carotid artery plaques with morphology as evaluated by B-mode ultrasound. DESIGN: Prospective study. MATERIAL AND METHODS: Seventy-eight symptomatic patients underwent carotid endarterectomy after preoperative ultrasound Duplex scanning evaluating plaque morphology. Morphometric analysis of the removed specimen was performed in order to quantify content of lipid, haemorrhage, calcification and fibrous tissue. RESULTS: Echolucent plaques contained more lipid (p = 0.01) and less calcification (p = 0.01) and fibrous tissue (p = 0.03) than echo-rich plaques. Intraplaque haemorrhage was directly related to lipid content (p = 0.004) and inversely related to amount of fibrous tissue in the plaque (p = 0.02). CONCLUSION: The intensity of the reflected B-mode ultrasound signal appears related to the histological composition of the plaque. The association between intraplaque haemorrhage and a high lipid content may support the theory of the lipid-rich plaque being more prone to rupture.

Histopathological features of in situ vein bypass stenoses.

OBJECTIVES: To analyse the histopathological features of in situ vein bypass stenoses. MATERIALS AND METHODS: Nineteen specimens of primary (n = 16) or recurrent (n = 3) vein graft stenoses obtained from 17 patients during surgical revision were prepared for light microscopy and immunohistochemical investigation. The median time interval from bypass surgery to stenosis excision was 5 months (range 2-52 months). Twenty-seven saphenous vein segments obtained from patients undergoing primary bypass surgery served as controls. RESULTS: Graft stenoses were characterised by moderate to severe intimal hyperplasia composed of actin positive but desmin negative cells, interspersed with areas of fibrosis. A single layer of factor VIII positive endothelial cells were identified on the luminal surface. The media, separated from the intima by a poorly defined elastic lamina, usually appeared normal or mildly hyperplastic and consisted of smooth muscle cells, which stained positive for actin as well as for desmin. The adventitia was composed of loose connective tissue in which lymphocytes, plasma cells and giant cells were occasionally seen. Atheromatous material was absent from intragraft lesions, but was observed in one specimen, which was harvested from a proximal anastomotic lesion. The majority of pre-bypass vein segments showed evidence of intimal thickening whereas medial hyperplasia was less common. CONCLUSIONS: In situ vein bypass stenoses mainly consisted of intimal hyperplasia and varying degrees of fibrosis. Similar but less pronounced morphological changes were found in pre-bypass vein segments. The nature of the actin positive but desmin and factor VIII negative intima cells is uncertain, and further studies are needed to characterise this cell type.

Echolucent carotid artery plaques are associated with elevated levels of fasting and postprandial triglyceride-rich lipoproteins.

BACKGROUND AND PURPOSE: Echolucent carotid atherosclerotic plaques are associated with an increased risk of neurological symptoms. Elevated plasma triglycerides is a risk factor for cerebral and coronary infarction. This study examined these individual pathogenetic risk factors to determine whether they were related. METHODS: We included 85 symptomatic patients with at least 40% carotid artery stenosis. Plaque morphology of the relevant artery was evaluated by high-resolution B-mode ultrasonography as echolucent, echo-rich, or intermediate. Fasting and postprandial lipids and lipoproteins were measured before and at hourly intervals for 4 hours after a fatty meal (1 g cream fat per kilogram body weight). RESULTS: When we compared patients with echolucent plaques to patients with echo-rich or intermediate plaques, the former had higher fasting and postprandial plasma triglycerides (P < or = .006), higher chylomicron remnants/VLDL cholesterol (P = .02) and triglycerides (P < or = .004), a larger area under the plasma triglyceride curve 0 to 4 hours after a fatty meal, with (AUCTG-TG oh) or without (AUCTG) subtraction of fasting levels (P = .007 and P = .003), a larger body mass index (P = .03), and were younger (P = .01). Multiple logistic regression analysis found that when age and body mass index were taken into account, fasting plasma and VLDL triglycerides, postprandial chylomicron remnants/VLDL triglycerides, AUCTG-TG oh and AUCTG with odds ratios of 4.1, 3.8, 3.0, 2.7, and 4.3, respectively, were independent predictors of an echolucent plaque. CONCLUSIONS: Echolucent carotid artery plaques are associated with elevated levels of triglyceride-rich lipoproteins in the fasting or postprandial state.