Accuracy of duplex sonography before carotid endarterectomy--a comparison with angiography

Transforming growth factor-β2 is associated with atherosclerotic plaque stability and lower risk for cardiovascular events

AIMS

Transforming growth factor-beta (TGF-β) exists in three isoforms TGF-β1, -β2, and -β3. TGF-β1 has been suggested to be important for maintaining plaque stability, yet the role of TGF-β2 and -β3 in atherosclerosis remains to be investigated.This study explores the association of the three isoforms of TGF-β with plaque stability in the human atherosclerotic disease.

METHODS AND RESULTS

TGF-β1, -β2, and -β3 proteins were quantified in 223 human carotid plaques by immunoassays. Indications for the endarterectomy were: symptomatic carotid plaque with stenosis >70% or without symptoms and >80% stenosis. Plaque mRNA levels were assessed by RNA sequencing. Plaque components and extracellular matrix were measured histologically and biochemically. Matrix metalloproteinases and monocyte chemoattractant protein-1 (MCP-1) was measured with immunoassays. The effect of TGF-β2 on inflammation and protease activity was investigated in vitro using THP-1 and RAW264.7 macrophages. Patients were followed longitudinally for cardiovascular (CV) events.TGF-β2 was the most abundant isoform and was increased at both protein and mRNA levels in asymptomatic plaques. TGF-β2 was the main determinant separating asymptomatic plaques in an Orthogonal Projections to Latent Structures Discriminant Analysis. TGF-β2 correlated positively to features of plaque stability and inversely to markers of plaque vulnerability. TGF-β2 was the only isoform inversely correlated to the matrix-degrading matrix metalloproteinase-9 and inflammation in the plaque tissue. In vitro, TGF-β2 pre-treatment reduced MCP-1 gene and protein levels as well as matrix metalloproteinase-9 gene levels and activity. Patients with plaques with high TGF-β2 levels had a lower risk to suffer from future CV events.

CONCLUSIONS

TGF-β2 is the most abundant TGF-β isoform in human plaques and may maintain plaque stability by decreasing inflammation and matrix degradation.

Duplex ultrasound for diagnosing symptomatic carotid stenosis in the extracranial segments

BACKGROUND

Carotid artery stenosis is an important cause of stroke and transient ischemic attack. Correctly and rapidly identifying patients with symptomatic carotid artery stenosis is essential for adequate treatment with early cerebral revascularization. Doubts about the diagnostic value regarding the accuracy of duplex ultrasound (DUS) and the possibility of using DUS as the single diagnostic test before carotid revascularization are still debated.

OBJECTIVES

To estimate the accuracy of DUS in individuals with symptomatic carotid stenosis verified by either digital subtraction angiography (DSA), computed tomography angiography (CTA), or magnetic resonance angiography (MRA).

SEARCH METHODS

We searched CRDTAS, CENTRAL, MEDLINE (Ovid), Embase (Ovid), ISI Web of Science, HTA, DARE, and LILACS up to 15 February 2021. We handsearched the reference lists of all included studies and other relevant publications and contacted experts in the field to identify additional studies or unpublished data.

SELECTION CRITERIA

We included studies assessing DUS accuracy against an acceptable reference standard (DSA, MRA, or CTA) in symptomatic patients. We considered the classification of carotid stenosis with DUS defined with validated duplex velocity criteria, and the NASCET criteria for carotid stenosis measures on DSA, MRA, and CTA. We excluded studies that included < 70% of symptomatic patients; the time between the index test and the reference standard was longer than four weeks or not described, or that presented no objective criteria to estimate carotid stenosis.

DATA COLLECTION AND ANALYSIS

The review authors independently screened articles, extracted data, and assessed the risk of bias and applicability concerns using the QUADAS-2 domain list. We extracted data with an effort to complete a 2 × 2 table (true positives, true negatives, false positives, and false negatives) for each of the different categories of carotid stenosis and reference standards. We produced forest plots and summary receiver operating characteristic (ROC) plots to summarize the data. Where meta-analysis was possible, we used a bivariate meta-analysis model.

MAIN RESULTS

We identified 25,087 unique studies, of which 22 were deemed eligible for inclusion (4957 carotid arteries). The risk of bias varied considerably across the studies, and studies were generally of moderate to low quality. We narratively described the results without meta-analysis in seven studies in which the criteria used to determine stenosis were too different from the duplex velocity criteria proposed in our protocol or studies that provided insufficient data to complete a 2 × 2 table for at least in one category of stenosis. Nine studies (2770 carotid arteries) presented DUS versus DSA results for 70% to 99% carotid artery stenosis, and two (685 carotid arteries) presented results from DUS versus CTA in this category. Seven studies presented results for occlusion with DSA as the reference standard and three with CTA as the reference standard. Five studies compared DUS versus DSA for 50% to 99% carotid artery stenosis. Only one study presented results from 50% to 69% carotid artery stenosis. For DUS versus DSA, for < 50% carotid artery stenosis, the summary sensitivity was 0.63 (95% confidence interval [CI] 0.48 to 0.76) and the summary specificity was 0.99 (95% CI 0.96 to 0.99); for the 50% to 69% range, only one study was included and meta-analysis not performed; for the 50% to 99% range, the summary sensitivity was 0.97 (95% CI 0.95 to 0.98) and the summary specificity was 0.70 (95% CI 0.67 to 0.73); for the 70% to 99% range, the summary sensitivity was 0.85 (95% CI 0.77 to 0.91) and the summary specificity was 0.98 (95% CI 0.74 to 0.90); for occlusion, the summary sensitivity was 0.91 (95% CI 0.81 to 0.97) and the summary specificity was 0.95 (95% CI 0.76 to 0.99). For sensitivity analyses, excluding studies in which participants were selected based on the presence of occlusion on DUS had an impact on specificity: 0.98 (95% CI 0.97 to 0.99). For DUS versus CTA, we found two studies in the range of 70% to 99%; the sensitivity varied from 0.57 to 0.94 and the specificity varied from 0.87 to 0.98. For occlusion, the summary sensitivity was 0.95 (95% CI 0.80 to 0.99) and the summary specificity was 0.91 (95% CI 0.09 to 0.99). For DUS versus MRA, there was one study with results for 50% to 99% carotid artery stenosis, with a sensitivity of 0.88 (95% CI 0.70 to 0.98) and specificity of 0.60 (95% CI 0.15 to 0.95); in the 70% to 99% range, two studies were included, with sensitivity that varied from 0.54 to 0.99 and specificity that varied from 0.78 to 0.89. We could perform only a few of the proposed sensitivity analyses because of the small number of studies included.

AUTHORS' CONCLUSIONS

This review provides evidence that the diagnostic accuracy of DUS is high, especially at discriminating between the presence or absence of significant carotid artery stenosis (< 50% or 50% to 99%). This evidence, plus its less invasive nature, supports the early use of DUS for the detection of carotid artery stenosis. The accuracy for 70% to 99% carotid artery stenosis and occlusion is high. Clinicians should exercise caution when using DUS as the single preoperative diagnostic method, and the limitations should be considered. There was little evidence of the accuracy of DUS when compared with CTA or MRA. The results of this review should be interpreted with caution because they are based on studies of low methodological quality, mainly due to the patient selection method. Methodological problems in participant inclusion criteria from the studies discussed above apparently influenced an overestimated estimate of prevalence values. Most of the studies included failed to precisely describe inclusion criteria and previous testing. Future diagnostic accuracy studies should include direct comparisons of the various modalities of diagnostic tests (mainly DUS, CTA, and MRA) for carotid artery stenosis since DSA is no longer considered to be the best method for diagnosing carotid stenosis and less invasive tests are now used as reference standards in clinical practice. Also, for future studies, the participant inclusion criteria require careful attention.

Human Atherosclerotic Plaque Progression Is Dependent on Apoptosis According to Bomb-Pulse 14C Dating

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Individuals with rapidly progressing atherosclerotic plaques are at higher risk to experience acute complications. Using a ¹⁴C bomb-pulse dating method, we explored the importance of different biological components for the timeframe of plaque progression in human atherosclerosis.

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According to the ¹⁴C bomb-pulse dating method, increased apoptosis was the main component associated with a young physical plaque age, reflecting a rapid progression.

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Physically young atherosclerotic plaques also had more apoptotic cells and larger cores than physically old plaques.

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Our findings in combination with recent advances in imaging techniques could guide future diagnostic imaging strategies to identify rapidly progressing plaques or therapeutic targets, halting plaque progression.

Individuals with rapidly progressing atherosclerotic plaques are at higher risk of experiencing acute complications. Currently, we lack knowledge regarding factors in human plaque that cause rapid progression. Using the ¹⁴C bomb-pulse dating method, we assessed the physical age of atherosclerotic plaques and which biological processes were associated with rapidly progressing plaques. Interestingly, increased apoptosis was the main component associated with a young physical plaque age, reflecting rapid plaque progression. Our findings in combination with recent advances in imaging techniques could guide future diagnostic imaging strategies to identify rapidly progressing plaques or therapeutic targets, halting plaque progression.

Plaque Vulnerability Index Predicts Cardiovascular Events: A Histological Study of an Endarterectomy Cohort

Background

The balance between stabilizing and destabilizing atherosclerotic plaque components is used in experimental studies and in imaging studies to identify rupture prone plaques. However, we lack the evidence that this balance predicts future cardiovascular events. Here we explore whether a calculated histological ratio, referred to as vulnerability index (VI), can predict patients at higher risk to suffer from future cardiovascular events.

Methods and Results

Carotid plaques and clinical information from 194 patients were studied. Tissue sections were used for histological analysis to calculate the VI (CD68 [cluster of differentiation 68], alpha‐actin, Oil red O, Movat pentachrome, and glycophorin A). Postoperative cardiovascular events were identified through the Swedish National Inpatient Health Register (2005–2013). During the follow‐up (60 months) 45 postoperative cardiovascular events were registered. Patients with a plaque VI in the fourth quartile compared with the first to third quartiles had significantly higher risk to suffer from a future cardiovascular event (P=0.0002). The VI was an independent predictor and none of the 5 histological variables analyzed separately predicted events. In the 13 patients who underwent bilateral carotid endarterectomy, the VI of the right plaque correlated with the VI of the left plaque and vice versa (r=0.7, P=0.01).

Conclusions

Our findings demonstrate that subjects with a high plaque VI have an increased risk of future cardiovascular events, independently of symptoms and other known cardiovascular risk factors . This strongly supports that techniques which image such plaques can facilitate risk stratification for subjects in need of more intense treatment.

Cell-specific and divergent roles of the CD40L-CD40 axis in atherosclerotic vascular disease

Atherosclerosis is a major underlying cause of cardiovascular disease. Previous studies showed that inhibition of the co-stimulatory CD40 ligand (CD40L)-CD40 signaling axis profoundly attenuates atherosclerosis. As CD40L exerts multiple functions depending on the cell-cell interactions involved, we sought to investigate the function of the most relevant CD40L-expressing cell types in atherosclerosis: T cells and platelets. Atherosclerosis-prone mice with a CD40L-deficiency in CD4⁺ T cells display impaired Th1 polarization, as reflected by reduced interferon-γ production, and smaller atherosclerotic plaques containing fewer T-cells, smaller necrotic cores, an increased number of smooth muscle cells and thicker fibrous caps. Mice with a corresponding CD40-deficiency in CD11c⁺ dendritic cells phenocopy these findings, suggesting that the T cell-dendritic cell CD40L-CD40 axis is crucial in atherogenesis. Accordingly, sCD40L/sCD40 and interferon-γ concentrations in carotid plaques and plasma are positively correlated in patients with cerebrovascular disease. Platelet-specific deficiency of CD40L does not affect atherogenesis but ameliorates atherothrombosis. Our results establish divergent and cell-specific roles of CD40L-CD40 in atherosclerosis, which has implications for therapeutic strategies targeting this pathway.

Near-occlusion is difficult to diagnose with common carotid ultrasound methods

Purpose

To assess the sensitivity and specificity of common carotid ultrasound method for carotid near-occlusion diagnosis.

Methods

Five hundred forty-eight patients examined with both ultrasound and CTA within 30 days of each other were analyzed. CTA graded by near-occlusion experts was used as reference standard. Low flow velocity, unusual findings, and commonly used flow velocity parameters were analyzed.

Results

One hundred three near-occlusions, 272 conventional ≥50% stenosis, 162 <50% stenosis, and 11 occlusions were included. Carotid ultrasound was 22% (95%CI 14–30%; 23/103) sensitive and 99% (95%CI 99–100%; 442/445) specific for near-occlusion diagnosis. Near-occlusions overlooked on ultrasound were found misdiagnosed as occlusions (n = 13, 13%), conventional ≥50% stenosis (n = 65, 63%) and < 50% stenosis (n = 2, 2%). No velocity parameter or combination of parameters could identify the 65 near-occlusions mistaken for conventional ≥50% stenoses with >75% sensitivity and specificity.

Conclusion

Near-occlusion is difficult to diagnose with commonly used carotid ultrasound methods. Improved carotid ultrasound methods are needed if ultrasound is to retain its position as sole preoperative modality.

Blood Flow Lateralization and Collateral Compensatory Mechanisms in Patients With Carotid Artery Stenosis

Background and Purpose- Four-dimensional phase-contrast magnetic resonance imaging enables quantification of blood flow rate (BFR; mL/min) in multiple cerebral arteries simultaneously, making it a promising technique for hemodynamic investigation in patients with stroke. The aim of this study was to quantify the hemodynamic disturbance and the compensatory pattern of collateral flow in patients with symptomatic carotid stenosis. Methods- Thirty-eight patients (mean, 72 years; 27 men) with symptomatic carotid stenosis (≥50%) or occlusion were investigated using 4-dimensional phase-contrast magnetic resonance imaging. For each patient, BFR was measured in 19 arteries/locations. The ipsilateral side to the symptomatic carotid stenosis was compared with the contralateral side. Results- Internal carotid artery BFR was lower on the ipsilateral side (134±87 versus 261±95 mL/min; P<0.001). BFR in anterior cerebral artery (A1 segment) was lower on ipsilateral side (35±58 versus 119±72 mL/min; P<0.001). Anterior cerebral artery territory bilaterally was primarily supplied by contralateral internal carotid artery. The ipsilateral internal carotid artery mainly supplied the ipsilateral middle cerebral artery (MCA) territory. MCA was also supplied by a reversed BFR found in the ophthalmic and the posterior communicating artery routes on the ipsilateral side (-5±28 versus 10±28 mL/min, P=0.001, and -2±12 versus 6±6 mL/min, P=0.03, respectively). Despite these compensations, BFR in MCA was lower on the ipsilateral side, and this laterality was more pronounced in patients with severe carotid stenosis (≥70%). Although comparing ipsilateral MCA BFR between stenosis groups (<70% and ≥70%), there was no difference ( P=0.95). Conclusions- With a novel approach using 4-dimensional phase-contrast magnetic resonance imaging, we could simultaneously quantify and rank the importance of collateral routes in patients with carotid stenosis. An important observation was that contralateral internal carotid artery mainly secured the bilateral anterior cerebral artery territory. Because of the collateral recruitment, compromised BFR in MCA is not necessarily related to the degree of carotid stenosis. These findings highlight the importance of simultaneous investigation of the hemodynamics of the entire cerebral arterial tree.

Carotid IM-GSM is better than IMT for identifying patients with multiple arterial disease

OBJECTIVE

Atherosclerosis is a systemic inflammatory disease that can affect more than one arterial bed simultaneously. The aim of this study was to determine the relationship between ultrasound markers of atherosclerosis and multiple arterial disease.

DESIGN

We have included 87 currently asymptomatic carotid disease patients (mean age 69 ± 6 year, 34% females) in this study. Intima media thickness (IMT) and intima media-grey scale median (IM-GSM) were measured in the common carotid artery (CCA), and correlated with previous and/or current atherosclerotic vascular disease in the coronary, carotid and lower extremities. Patients were divided into three groups: (1) asymptomatic, (2) previous symptoms in one arterial territory and (3) previous symptoms in multiple arterial territories.

RESULTS

Patients with previous disease in the coronary arteries had higher IMT (p = .034) and lower IM-GSM (p < .001), and those with prior stroke had lower IM-GSM (p = .007). Neither IMT nor IM-GSM was different between patients with and without previous lower extremity vascular disease. IM-GSM was significantly different between groups, it decreased significantly with increasing number of arterial territories affected (37.7 ± 15.4 vs. 29.3 ± 16.4 vs. 20.7 ± 12.9) p < .001, for asymptomatic, symptoms in one and in multiple arterial systems, respectively. Conventional IMT was not significantly different between groups p = .49.

CONCLUSION

Carotid IMT was higher and IM-GSM lower in patients with symptomatic nearby arterial territories but not in those with peripheral disease. In contrast to conventional IMT, IM-GSM can differentiate between numbers of arterial territories affected by atherosclerosis, suggesting that it is a better surrogate for monitoring multiple arterial territory disease.

Spotty Carotid Plaques Are Associated with Inflammation and the Occurrence of Cerebrovascular Symptoms

Background

Echolucent carotid plaques have been related to an increased risk of ischemic cerebrovascular events. The aim of the present study was to evaluate whether a new objective ultrasonographic parameter, the statistical geometric feature (SGF), reflecting spottiness of carotid plaques, can be associated with cerebrovascular symptoms and with a rupture-prone plaque phenotype.

Methods

The plaques of 144 patients who underwent carotid endarterectomy were included in this study. SGF and plaque area were estimated by outlining the plaque on ultrasound (US) images. The correlation coefficient for inter- and intraobserver variability was 0.69 and 0.93, respectively. The SGF values were normalized to the degree of stenosis (SGF/DS). The plaques collected at surgery 1 day after the US were analyzed histologically, and inflammatory markers and matrix metalloproteinases (MMPs) were measured.

Results

Patients with ipsilateral hemispheric symptoms had higher SGF/DS compared to patients without symptoms (0.82 [0.59–1.16] vs. 0.70 [0.56–0.89], p = 0.01). Analysis of plaque components revealed a positive correlation between SGF/DS and the percentage of the plaque area stained for lipids, macrophages, and hemorrhage. A correlation was also found between SGF/DS and plaque expression of interleukin-6, monocyte chemoattractant protein-1, macrophage inflammatory protein-1β, vascular endothelial growth factor A, C-C motif chemokine 3 and 20, and MMP-9. An inverse correlation was found with plaque levels of osteoprotegerin.

Conclusions

The present study supports the concept that spottiness is a feature of the carotid plaques rich in inflammation and can be associated with the typical phenotype of high-risk plaques.

Carotid calcification in panoramic radiographs: radiographic appearance and the degree of carotid stenosis

OBJECTIVES:

Approximately 7% of patients examined with panoramic radiographs (PRs) for odontological reasons, and with incidental findings of carotid artery calcification (CAC), have significant (≥50%) carotid stenosis (SCS). The aim of this study was to determine if the radiographic appearance of CACs in PRs could be categorized such that we could improve the positive-predictive value (PPV) for SCS detection.

METHODS:

This cross-sectional study included 278 patients with CACs identified by PRs, 127 with SCS and 151 without SCS. CACs were categorized based on the following appearances: (1) single, (2) scattered or (3) vessel-outlining. Correlates were derived for each category according to positivity or not for SCS in the corresponding neck sides. For a representative adult population (in dentistry) presenting with CACs in PRs, PPVs for SCS prediction were then calculated for three subgroups based on different combinations of appearances (2) and/or (3).

RESULTS:

Vessel-outlining CACs corresponded to 65% of neck sides with SCS vs 47% without SCS (p < 0.001). Single CACs corresponded to 15% of neck sides with SCS vs 27% without SCS (p = 0.006). Scattered CACs corresponded to 20% of neck sides with SCS vs 26% without SCS (p = 0.127). In the representative population, the PPVs for SCS detection were comparable (7.2-7.8%) for all three subgroups and when the presence of a CAC is the sole criterion (7.4%).

CONCLUSIONS:

Stratifying the radiographic appearance of CACs in PRs does not improve the PPV for SCS detection. Whether different radiographic appearances are associated with future risk of stroke, or other cardiovascular events, remains unknown.

Recurrent stroke in symptomatic carotid stenosis awaiting revascularization: A pooled analysis

OBJECTIVE

We aimed to quantify the risk and predictors of ipsilateral ischemic stroke in patients with symptomatic carotid stenosis awaiting revascularization (carotid endarterectomy [CEA] or carotid artery stenting) by pooling individual patient data from recent prospective studies with high rates of treatment with modern stroke prevention medications.

METHODS

Data were included from 2 prospective hospital-based registries (Umeå, Barcelona) and one prospective population-based study (Dublin). Patients with symptomatic 50%-99% carotid stenosis eligible for carotid revascularization were included and followed for early recurrent ipsilateral stroke or retinal artery occlusion (RAO).

RESULTS

Of 607 patients with symptomatic 50%-99% carotid stenosis, 377 met prespecified inclusion criteria. Ipsilateral recurrent ischemic stroke/RAO risk pre-revascularization was 2.7% (1 day), 5.3% (3 days), 11.5% (14 days), and 18.8% (90 days). On bivariate analysis, presentation with a cerebral vs ocular event was associated with higher recurrent stroke risk (log-rank p = 0.04). On multivariable Cox regression, recurrence was associated with older age (adjusted hazard ratio [HR] per 10-year increase 1.5, p = 0.02) with a strong trend for association with cerebral (stroke/TIA) vs ocular symptoms (adjusted HR 2.7, p = 0.06), but not degree of stenosis, smoking, vascular risk factors, or medications.

CONCLUSIONS

We found high risk of recurrent ipsilateral ischemic events within the 14-day time period currently recommended for CEA. Randomized trials are needed to determine the benefits and safety of urgent vs subacute carotid revascularization within 14 days after symptom onset.

Direct association between diet and the stability of human atherosclerotic plaque

Mediterranean diet has been suggested to explain why coronary heart disease mortality is lower in southern than northern Europe. Dietary habits can be revealed by isotope ratio mass spectrometry (IRMS) measurement of carbon (δ(13)C) and nitrogen (δ(15)N) in biological tissues. To study if diet is associated with human plaque stability, atherosclerotic plaques from carotid endarterectomy on 56 patients (21 Portuguese and 35 Swedish) were analysed by IRMS and histology. Plaque components affecting rupture risk were measured. Swedish plaques had more apoptosis, lipids and larger cores, as well as fewer proliferating cells and SMC than the Portuguese, conferring the Swedish a more rupture-prone phenotype. Portuguese plaques contained higher δ(13)C and δ(15)N than the Swedish, indicating that Portuguese plaques were more often derived from marine food. Plaque δ(13)C correlated with SMC and proliferating cells, and inversely with lipids, core size, apoptosis. Plaque δ(15)N correlated with SMC and inversely with lipids, core size and apoptosis. This is the first observational study showing that diet is reflected in plaque components associated with its vulnerability. The Portuguese plaques composition is consistent with an increased marine food intake and those plaques are more stable than those from Swedish patients. Marine-derived food is associated with plaque stability.

Common carotid intima-media features determine distal disease phenotype and vulnerability in asymptomatic patients

OBJECTIVES

There is a growing awareness of the importance of carotid plaque features evaluation in stroke prediction. Carotid intima-media thickness (IMT) and recently its echogenicity were used for stroke prediction, although their clinical relevance was not well determined. The aim of this study was to assess the relationship between common carotid artery (CCA) ultrasound markers of atherosclerosis and distal, bifurcation and internal carotid artery (ICA), plaque features.

METHODS

We analyzed 137 carotid arteries in 87 asymptomatic patients with known carotid disease (mean age 69 ± 6 year, 34.5% females). Intima media thickness (IMT) and its gray scale median (IM-GSM) were measured at the CCA. Plaque textural features including gray scale median (GSM), juxtaluminal black area (JBA-mm(2)) without a visible cap, and plaque coarseness, at bifurcation and ICA were also determined. CCA measurements were correlated with those of the distal plaques.

RESULTS

An increased IMT in CCA correlated with plaque irregularities in the bifurcation and ICA (r=0.53, p<0.001), while IM-GSM was closely related to plaque echogenicity (GSM) (r=0.76, p<0.001), and other textural plaque features. Both, IMT and IM-GSM correlated weakly with stenosis severity (r=0.27, p=0.001 and r=-0.18, p=0.026) respectively.

CONCLUSION

In asymptomatic patients, measurements of CCA reflect distal, bifurcation and ICA disease, with IMT reflecting plaque irregularities and IM-GSM as markers of textural plaque abnormalities. Integrating measurements of both IMT and IM-GSM in a model could be used as a better marker of disease vulnerability over and above each measure individually.

Atherosclerotic Calcification Detection: A Comparative Study of Carotid Ultrasound and Cone Beam CT

BACKGROUND AND AIM

Arterial calcification is often detected on ultrasound examination but its diagnostic accuracy is not well validated. The aim of this study was to determine the accuracy of carotid ultrasound B mode findings in detecting atherosclerotic calcification quantified by cone beam computed tomography (CBCT).

METHODS

We analyzed 94 carotid arteries, from 88 patients (mean age 70 ± 7 years, 33% females), who underwent pre-endarterectomy ultrasound examination. Plaques with high echogenic nodules and posterior shadowing were considered calcified. After surgery, the excised plaques were examined using CBCT, from which the calcification volume (mm3) was calculated. In cases with multiple calcifications the largest calcification nodule volume was used to represent the plaque. Carotid artery calcification by the two imaging techniques was compared using conventional correlations.

RESULTS

Carotid ultrasound was highly accurate in detecting the presence of calcification; with a sensitivity of 88.2%. Based on the quartile ranges of calcification volumes measured by CBCT we have divided plaque calcification into four groups: <8; 8-35; 36-70 and >70 mm3. Calcification volumes ≥8 were accurately detectable by ultrasound with a sensitivity of 96%. Of the 21 plaques with <8 mm3 calcification volume; only 13 were detected by ultrasound; resulting in a sensitivity of 62%. There was no difference in the volume of calcification between symptomatic and asymptomatic patients.

CONCLUSION

Carotid ultrasound is highly accurate in detecting the presence of calcified atherosclerotic lesions of volume ≥8 mm3; but less accurate in detecting smaller volume calcified plaques. Further development of ultrasound techniques should allow better detection of early arterial calcification.

Symptomatic carotid near-occlusion with full collapse might cause a very high risk of stroke

BACKGROUND

The risk of early stroke recurrence amongst patients with symptomatic carotid near-occlusion with and without full collapse is unknown. Therefore, the aim of this study was to analyse the 90-day risk of recurrent ipsilateral ischaemic stroke in patients with symptomatic carotid near-occlusion both with and without full collapse.

METHODS

This study was a secondary analysis of the Additional Neurological SYmptoms before Surgery of the Carotid Arteries: a Prospective study (ANSYSCAP). We prospectively analysed 230 consecutive patients with symptomatic 50-99% carotid stenosis or near-occlusion. Based on the combination of several imaging modalities, 205 (89%) patients were classified as having 50-99% carotid stenosis, and 10 (4%) and 15 (7%) as having near-occlusion with and without full collapse, respectively. The 90-day risk of recurrent ipsilateral ischaemic stroke was compared between these three groups. Only events that occurred before carotid endarterectomy were analysed.

RESULTS

The 90-day risk of recurrent stroke was 18% [95% confidence interval (CI) 12-25%; n = 29] for patients with 50-99% carotid stenosis, 0% for patients with near-occlusion without full collapse and 43% (95% CI 25-89%; n = 4) for patients with near-occlusion with full collapse (P = 0.035, log-rank test). The increased risk of recurrent ipsilateral ischaemic stroke for patients with symptomatic near-occlusion with full collapse remained significant after multivariable adjustment for age, sex and type of presenting event.

CONCLUSIONS

Patients with symptomatic carotid near-occlusion with full collapse might have a very high risk of stroke recurrence. Carotid endarterectomy could be considered for these patients.

Low elastin content of carotid plaques is associated with increased risk of ipsilateral stroke

OBJECTIVES

Atherosclerotic plaques with a low content of connective tissue proteins are believed to have an increased risk of rupture and to give rise to clinical events. The aim of the present study was to investigate if the content of elastin, collagen and of the matrix metalloproteinase (MMP) -1, -3, -9 and -12 in plaques removed at surgery can be associated with the occurrence of ipsilateral symptoms.

METHODS

The atherosclerotic plaques of 221 patients undergoing carotid endarterectomy were analyzed and their composition was related to the incidence of preoperative, intraoperative and postoperative neurological events.

RESULTS

Elastin, collagen and MMP-12 contents were lower in males and diabetic patients. Elastin (P .010), MMP-3 (P .008) and MMP-9 (P < .0001) were lower, while MMP-1 (P .004) and MMP-9 (P .002) were higher in plaques of patients with preoperative symptoms, even after correction for the time between the occurrence of symptoms and surgery. Elastin and MMP-12 decreased (r = -0.17, P .009 and r = -.288, P <.0001 respectively) while MMP-1 (r = 0.17, P .012) and MMP-9 (r = .21 P <.0001) increased with age. After a mean follow-up time of 39.6 ± 16.6 months, 7.7% of patients had suffered one or multiple ipsilateral neurological events. Patients with plaque elastin levels lower than the median (52 mg/g) had increased post-operative incidence of ipsilateral stroke (P for trend 0.009 using Log Rank Chi-square test). This finding was confirmed when controlling for age, gender, hypertension, diabetes, smoking, pre-operative symptoms and statin usage in a Cox Proportional Hazard model (hazard ratio 7.38, 95% C.I. 1.50-36.31).

CONCLUSIONS

These observations support the concept that elastin may be important for plaque stability, and suggest that a low plaque content of elastin is associated with a higher risk for ipsilateral stroke.

Treatment with betablockers is associated with higher grey-scale median in carotid plaques

Background

The presence of echolucent carotid plaques as defined by low ultrasound grey-scale median (GSM) is associated with a higher risk of stroke and myocardial infarction. Betablockers have shown possible anti-atherosclerotic effects. The aim of the present study was to determine if there is an association between carotid plaque GSM and treatment with betablockers.

Methods

The GSM of the carotid plaques of 350 patients who underwent carotid endarterectomy (CEA) for asymptomatic (n = 113) or symptomatic (n = 237) carotid disease was measured. Patients were divided in two groups based on the absence/presence of an on-going long-term (i.e. at least 6 months) oral treatment with betablockers at the time of CEA.

Results

The prevalence and type of preoperative neurological symptoms were similar in the two groups. Patients with betablockers had more frequently arterial hypertension (P < .0001), diabetes (P = .035) and a higher BMI (P = .0004), while patients without betablockers were most frequently smokers (P = .017).

Patients with betablockers revealed to have higher GSM (37.79 ± 25 vs 32.61 ± 23.50 P = .036). Echogenic plaques (i.e. with GSM > 30) showed to be more frequent in patients with betablockers also after correction for age, gender, the occurrence of preoperative symptoms, diabetes, hypertension, smoking and statins use (P = .024).

Conclusions

These results suggest the use of standardized ultrasound techniques as an important tool in evaluating the effect of anti-atherosclerotic medications and underline the need of.further prospective randomized studies on larger patient cohorts in order to confirm these results.

Vulnerable plaques in the contralateral carotid arteries in symptomatic patients: a detailed ultrasound analysis

BACKGROUND AND AIM

Carotid plaques may represent a generalized atherosclerotic syndrome or a localized disease. The aim of this study was to assess the morphological and textural features of carotid plaques located contralateral to the symptomatic side and compare them with the symptomatic side and with plaques from asymptomatic patients.

METHODS

We studied 66 arteries in 39 patients (mean age 70 ± 7 year, 33% females). Arterial plaques were classified as either symptomatic (n = 30), contralateral to symptomatic (n = 25) or asymptomatic (n = 11). We compared several plaque features between these groups including the mean values of the grey scale median (GSM), entropy, juxtaluminal black area (JBA) without visible echogenic cap, GSM of the JBA and surface irregularity.

RESULTS

The plaques contralateral to symptomatic arteries had similar morphological and textural features to those in the symptomatic arteries. In contrast, they had more vulnerable morphological and textural features than those in asymptomatic arteries: less smooth plaques (12% vs. 55%) and instead more often mildly irregular (60% vs 36%) or markedly irregular (28% vs. 9%; p = 0.03), lower GSM (26.2 ± 8 vs. 49.4 ± 14, p < 0.001) and lower GSM of the JBA (5.0 ± 3.6 vs. 11.4 ± 2.1, p = 0.008). The frequency of entropy and plaque calcification was similar in all groups.

CONCLUSION

Symptomatic patients with carotid artery disease seem to have similar morphological and textural features of vulnerability in the symptomatic and the contralateral carotid arteries, which are profound compared with asymptomatic carotid arteries. These findings support the concept of generalized carotid atherosclerotic pathology rather than incidental unilateral disease, and also emphasize a need for aggressive measures for plaque stabilization, particularly in symptomatic patients.

Detection of calcifications in panoramic radiographs in patients with carotid stenoses ≥50%

OBJECTIVE

Carotid stenoses ≥50% are associated with increased risk for stroke that can be reduced by prophylactic carotid endarterectomy (CEA). Calcifications in arteries can be detected in panoramic radiographs (PRs). In a cross-sectional study, we analyzed (1) extirpated plaques for calcification, (2) how often PRs disclosed calcified plaques, (3) how often patients with stenoses ≥50% presented calcifications in PRs, and (4) the additional value of frontal radiographs (FRs).

STUDY DESIGN

Patients (n = 100) with carotid stenosis ≥50% were examined with PRs and FRs before CEA. Extirpated carotid plaques were radiographically examined (n = 101).

RESULTS

It was found that 100 of 101 (99%) extirpated plaques were calcified, of which 75 of 100 (75%) were detected in PRs; 84 of 100 (84%) patients presented carotid calcifications in the PRs, in 9.5% contralateral to the stenosis ≥50%.

CONCLUSIONS

Carotid calcifications are seen in PRs in 84% of patients with carotid stenosis ≥50%, independent of gender. FRs do not contribute significantly to this identification.

Treatment with beta-blockers is associated with lower levels of Lp-PLA2 and suPAR in carotid plaques

OBJECTIVES

To determine whether a long-term treatment with beta-blockers influences the inflammatory activity in carotid artery disease by reducing the carotid plaque levels of lipoprotein-associated phospholipase A2 (Lp-PLA2), its enzymatic products lysophosphatidylcholine (lysoPCs), and of soluble urokinase plasminogen activator receptor (suPAR).

MATERIALS AND METHODS

One hundred and thirty-four patients with significant symptomatic or asymptomatic carotid stenosis undergoing surgery were prospectively included and divided into two groups (Group A or B) based on the absence or presence of an on-going long-term oral treatment with beta-blockers. The harvested carotid plaques were analyzed for the levels of lysoPCs using mass spectrometry and Lp-PLA2 and suPAR by Enzyme-linked immunosorbent assay (ELISA).

RESULTS

Plaques of patients on long-term treatment with beta-blockers revealed lower levels of Lp-PLA2 (Group A 0.752 ± 0.393 ug/g vs. Group B 0.644 ± 0.445 ug/g, P=.049) as well as suPAR (Group A 0.044 ± 0.024 μg/g vs. Group B 0.036 ± 0.025 μg/g, P=.028). Levels of Lp-PLA2 and suPAR were positively correlated (r=.637, P<.0001). Lp-PLA2 and suPAR levels were also correlated (P<.0001) with the three lysoPC species tested (lysoPC 16:0, lysoPC 18:0. lysoPC 18:1). All the above-mentioned findings were confirmed after correction for age, gender, hypertension, coronary artery disease, and statin usage.

CONCLUSIONS

The reduced levels of Lp-PLA2 and suPAR in human carotid plaques of subjects on long-term treatment with beta-blockers suggest their possible protective role in plaque inflammation. Our findings support an even more selective Lp-PLA2 and suPAR inhibition as a possible strategy for the prevention of cardiovascular disease.

Carotid velocities determine cerebral blood flow deficits in elderly men with carotid stenosis <50%

To examine if mild carotid stenosis correlates with silent vascular brain changes, we studied a prospective population-based cohort “Men born in 1914.” Data from followups at ages 68 and 81, have been used. Carotid ultrasound was performed at age 81, and cerebral blood flow (CBF) was measured with SPECT at age 82. Out of 123 stroke-free patients, carotid stenosis <50% was observed in 94% in the right and 89% in the left internal carotid arteries (ICAs). In these subjects, Peak Systolic Velocities in ICA correlated negatively with CBF in a majority of several brain areas, especially in mesial temporal area. Results were limited to normotensive until their seventies, who developed late-onset hypertension with a subsequent blood pressure, pulse pressure, and ankle-brachial index growth. Elderly with asymptomatic carotid stenosis <50% and peak systolic velocities in ICA 0.7–1.3 m/s, should be offered an intensified pharmacotherapy to prevent stroke or silent cerebrovascular events.

Risk of Recurrent Stroke before Carotid Endarterectomy: The ANSYSCAP Study

Background

Carotid endarterectomy yields greater risk reduction for ipsilateral ischemic stroke when performed within two-weeks of the last cerebrovascular symptom than when performed two-weeks or more after the last symptom. However, additional benefit might be gained if carotid endarterectomy is performed earlier than within two-weeks.

Aims

To investigate the 90-day risk of ipsilateral ischemic stroke recurrence after amaurosis fugax, retinal artery occlusion, transient ischemic attack, or minor ischemic stroke in patients with 50–99% carotid stenosis before carotid endarterectomy, with emphasis on the first 14 days.

Methods

Prospective cohort study. 230 consecutive patients with symptomatic 50–99% carotid stenosis (North American Symptomatic Carotid Endarterectomy Trial grading method) who underwent evaluation before carotid endarterectomy. Of these, 183 underwent carotid endarterectomy; the median delay to carotid endarterectomy was 29 days. Blood pressure lowering medication was used by 93% and lipid-lowering medication by 90%.

Results

The risk of ipsilateral ischemic stroke recurrence before carotid endarterectomy was 5·2% ( n = 12) within two-days, 7·9% ( n = 18) within seven-days, 11·2% ( n = 25) within 14 days, and 18·6% ( n = 33) within 90 days of the presenting event. The risk of ipsilateral ischemic stroke recurrence was higher if the presenting event was a stroke (adjusted hazard ratio 12·4, P = 0·015) or transient ischemic attack (adjusted hazard ratio 10·2, P = 0·026) compared with an amaurosis fugax.

Discussion

The risk of recurrent ipsilateral ischemic stroke was high within the first days of the presenting event. Many recurrences would likely have been avoided if carotid endarterectomy had been performed within the first days of the presenting event.

Ultrasound screening for asymptomatic carotid stenosis in subjects with calcifications in the area of the carotid arteries on panoramic radiographs: a cross-sectional study

BACKGROUND

Directed ultrasonic screening for carotid stenosis is cost-effective in populations with > 5% prevalence of the diagnosis. Occasionally, calcifications in the area of the carotid arteries are incidentally detected on odontological panoramic radiographs. We aimed to determine if directed screening for carotid stenosis with ultrasound is indicated in individuals with such calcifications.

METHODS

This was a cross-sectional study. Carotid ultrasound examinations were performed on consecutive persons, with findings of calcifications in the area of the carotid arteries on panoramic radiography that were otherwise eligible for asymptomatic carotid endarterectomy.

RESULTS

Calcification in the area of the carotid arteries was seen in 176 of 1182 persons undergoing panoramic radiography. Of these, 117 fulfilled the inclusion criterion and were examined with carotid ultrasound. Eight persons (6.8%; 95% CI 2.2-11.5%) had a carotid stenosis--not significant over the 5% pre-specified threshold (p = 0.232, Binomial test). However, there was a significant sex difference (p = 0.008), as all stenoses were found in men. Among men, 12.5% (95%CI 4.2-20.8%) had carotid stenosis--significantly over the 5% pre-specified threshold (p = 0.014, Binomial test).

CONCLUSIONS

The incidental finding of calcification in the area of the carotid arteries on panoramic radiographs should be followed up with carotid screening in men that are otherwise eligible for asymptomatic carotid endarterectomy.

TRIAL REGISTRATION

The study was registered at http://www.clinicaltrials.gov; NCT00514644.

Changing From Conventional to Eversion Endarterectomy in Carotid Artery Disease—A Safe Transition Process in the Short and Long Term

Objectives: To evaluate the transition process from conventional carotid endarterectomy (cCEA) to eversion carotid endarterectomy (eCEA). Methods: Patients operated with carotid endarterectomy (CEA; 164 patients, 171 CEA) in 2002-2003 were retrospectively included. Results: In 2002, cCEA was applied in 64 (80%) and eCEA in 16 (20%) patients. There was an inversion on the preponderant surgical technique in 2003 (cCEA in 34 patients [37%] and eCEA in 57 patients [63%]). Perioperative stroke or death occurred in 3 patients (3.8%) in 2002 and 5 (5.5%) in 2003 (P = .78). Perioperative myocardial infarction occurred in 2 patients (2.5%) in 2002 and 2 in 2003 (2.2%, P = 1.00). Median follow-up was 83 (79-86) and 70 (67-74) months for the 2002 and 2003 cohorts, respectively, and there were no differences in survival or ipsilateral stroke between the groups. Conclusions: The transition from cCEA to eCEA is possible without significant changes in morbidity and mortality perioperatively and during follow-up.

[Internal carotid artery occlusion or subocclusion--contemporary diagnostic challenges: case report]

INTRODUCTION

Measurement of vessel stenosis using ultrasonography or magnetic resonance is still the principal method for determining the severity of carotid atherosclerosis and need for endarterectomy.

CASE OUTLINE

A 56-year-old male was admitted to the Cardiovascular Institute "Dedinje" due to a clinically asymptomatic restenosis of the operated left internal carotid artery (ICA). Angiography and magnetic resonance angiography (MRA) in previous hospitalization had revealed occluded right ICA. However, routine duplex ultrasonography revealed a high-grade restenosis (85%) of the left ICA and subocclusion of the right ICA by an ulcerated plaque (confirmed on repeated MRA).

CONCLUSION

Selective arteriography examination could misrepresent the degree of stenosis especially in patents with the ICA that seems to be occluded. MRA is considered the method of choice for identifying pseudo-occlusions of ICA.

Carotid bruits as predictor for carotid stenoses detected by ultrasonography: an observational study

Background

Carotid surgery in asymptomatic subjects with carotid stenosis is effective to prevent ischemic stroke. There is, however, uncertainty how to find such persons at risk, because mass screening with carotid artery ultrasonography (US) is not cost-effective. Signs of carotid bruits corresponding to the carotid arteries may serve as a tool to select subjects for further investigation. This study is thus aimed at determining the usefulness of carotid bruits in the screening of carotid stenoses.

Methods

1555 consecutive carotid ultrasonography investigations from 1486 cases done between January 2004 and March 2006 at Norrlands University Hospital, Sweden, were examined. 356 subjects, medium age 69 (27–88) years, had a significant (≥ 50%) US-verified carotid stenosis uni- or bilaterally, 291 had been examined for signs of carotid bruits. The likelihood ratios for carotid bruits to predict US-verified carotid stenoses were calculated and expressed as likelihood percentages.

Results

Thirty-one out of 100 persons (31%) with carotid bruit as an indication to perform carotid US had a significant (≥ 50%) carotid stenosis. 281 of the 356 (79%) cases with significant carotid stenoses were found among patients with cerebrovascular disease (CVD). 145 of 226 (64%) CVD patients with a significant carotid stenosis had a carotid bruit. In patients with 50–99% carotid stenoses carotid bruits had an accuracy of 75% (436/582), a sensitivity of 71% (236/334), a specificity of 81% (200/248), a positive likelihood ratio at 3.65 and a negative likelihood at 0.36. Patients with 70–99% stenoses had the highest sensitivity at 77% (183/238). In patients with 100% carotid stenoses, carotid bruits had a sensitivity of 26% (15/57) and a specificity of 49% (256/525).

Conclusion

Although carotid bruits are not accurate to confirm or to exclude significant carotid stenoses, these signs are appropriate for directed screening for further investigation with carotid US if the patient lacks contraindications for surgery. Lack of carotid bruits in CVD patients does not exclude a carotid stenosis.

Delay from symptoms to carotid endarterectomy

OBJECTIVES

To investigate the time between cerebrovascular symptom and carotid endarterectomy (CEA), what prolongs this time and if and when the patients suffer additional cerebrovascular events.

DESIGN

Observational.

SETTING

Single Centre study at a specialized Stroke Centre.

SUBJECTS

A total of 275 patients with > or =50% symptomatic carotid stenosis (according to the NASCET-criteria) between 1 January 2004 and 31 March 2006.

MAIN OUTCOME MEASURES

Time between cerebrovascular symptom and CEA, time between different parts of the investigation, additional cerebrovascular symptoms before CEA and as perioperative complication.

RESULTS

A total of 128 patients underwent CEA. The median time between symptom and CEA was 11.7 weeks in the beginning and 6.9 weeks at the end of the study. Seven per cent were operated within 2 weeks and 11% between 2 and 4 weeks after their cerebrovascular symptom. The time delays were most pronounced between symptom onset and arrival at the Umeå Stroke Centre from the secondary hospitals and between the decision to recommend CEA and the CEA. Twenty-eight per cent of the patients who were intended for surgery suffered additional cerebrovascular events, 1.4% suffered a major stroke which excluded the indication of CEA and 3.0% of the CEA patients suffered a stroke with functional dependence within 30 days of the operation.

CONCLUSIONS

The delay between symptom and CEA was substantially longer than the desired 2 weeks. Many patients suffered additional cerebrovascular events before CEA. The risk of a severe additional stroke before CEA was about the same as the risk of a severe complication from the CEA.

Increased Echolucency of Carotid Plaques in Patients With Type 2 Diabetes

BACKGROUND AND PURPOSE

Diabetes is associated with the presence of moderate to large atherosclerotic carotid plaques. Previous carotid ultrasound studies have associated plaques with low echogenicity with a higher risk of cerebrovascular events. The aim of this study was to evaluate whether patients with type 2 diabetes have different plaque echogenicity than do nondiabetic subjects.

METHODS

Forty-seven type 2 diabetic and 51 nondiabetic subjects with a carotid plaque in the right artery were included in this study. All patients were born in 1935 to 1936 and were participants in a population-based study. Carotid ultrasonography was performed and the risk factors for cardiovascular disease were determined. Plaque echogenicity was assessed quantitatively on B-mode ultrasound images by standardized gray-scale median values.

RESULTS

Gray-scale median values were significantly lower, indicating more echolucent plaques, in patients with type 2 diabetes compared with nondiabetics (37.0+/-14.8 vs 45.5+/-15.4, P=0.007). Of the other risk factors studied, only triglycerides were significantly associated with the echogenicity of the plaque.

CONCLUSIONS

Patients with type 2 diabetes have more echolucent plaques compared with nondiabetic subjects. This might be associated with the higher risk of cardiovascular events among diabetics.

Duplex ultrasound and magnetic resonance angiography compared with digital subtraction angiography in carotid artery stenosis: a systematic review

BACKGROUND AND PURPOSE

The purpose of this work was to review and compare published data on the diagnostic value of duplex ultrasonography (DUS), MR angiography (MRA), and conventional digital subtraction angiography (DSA) for the diagnosis of carotid artery stenosis.

METHODS

We performed a systematic review of published studies retrieved through PUBMED, from bibliographies of review papers, and from experts. The English-language medical literature was searched for studies that met the selection criteria: (1) The study was published between 1994 and 2001; (2) MRA and/or DUS was performed to estimate the severity of carotid artery stenosis; (3) DSA was used as the standard of reference; and (4) the absolute numbers of true positives, false negatives, true negatives, and false positives were available or derivable for at least one definition of disease (degree of stenosis).

RESULTS

Sixty-three publications on duplex, MRA, or both were included in the analysis, yielding the test results of 64 different patient series on DUS and 21 on MRA. For the diagnosis of 70% to 99% versus <70% stenosis, MRA had a pooled sensitivity of 95% (95% CI, 92 to 97) and a pooled specificity of 90% (95% CI, 86 to 93). These numbers were 86% (95% CI, 84 to 89) and 87% (95% CI, 84 to 90) for DUS, respectively. For recognizing occlusion, MRA yielded a sensitivity of 98% (95% CI, 94 to 100) and a specificity of 100% (95% CI, 99 to 100), and DUS had a sensitivity of 96% (95% CI, 94 to 98) and a specificity of 100% (95% CI, 99 to 100). A multivariable summary receiver-operating characteristic curve (ROC) analysis for diagnosing 70% to 99% stenosis demonstrated that the type of MR scanner predicted the performance of MRA, whereas the presence of verification bias predicted the performance of DUS. For diagnosing occlusion, no significant heterogeneity was found for MRA; for DUS, the presence of verification bias and type of DUS scanner were explanatory variables. MRA had a significantly better discriminatory power than DUS in diagnosing 70% to 99% stenosis (regression coefficient, 1.6; 95% CI, 0.37 to 2.77). No significant difference was found in detecting occlusion (regression coefficient, 0.73; 95% CI, -2.06 to 3.51).

CONCLUSIONS

These results suggest that MRA has a better discriminatory power compared with DUS in diagnosing 70% to 99% stenosis and is a sensitive and specific test compared with DSA in the evaluation of carotid artery stenosis. For detecting occlusion, both DUS and MRA are very accurate.

Duplex sonographic criteria for measuring carotid stenoses

PURPOSE

The aim of this retrospective study was to determine optimal duplex sonographic criteria for use in our institution for diagnosing severe carotid stenoses and to correlate those findings with angiographic measurements obtained by the European Carotid Surgery Trial (ECST), North American Symptomatic Carotid Endarterectomy Trial (NASCET), and Common Carotid (CC) methods of grading carotid stenoses.

METHODS

We analyzed the angiographic data using the ECST, NASCET, and CC methods and compared the results with the duplex sonographic findings. We then calculated the sensitivity, specificity, positive and negative predictive values, and accuracy of the duplex sonographic method. Taking these parameters into account, the optimal intrastenotic peak systolic velocity (PSV) and end diastolic velocity (EDV) were derived for diagnosing severe stenoses according to the 3 angiographic methods.

RESULTS

Optimal PSV and EDV values for diagnosing a 70% or greater stenosis in our laboratory were as follows: with the NASCET method of angiographic grading of stenoses, PSV 220 cm/second or greater and EDV 80 cm/second or greater, and with the ECST and CC methods, PSV 190 cm/second or greater, and EDV 65 cm/second or greater. The optimal PSV and EDV for diagnosing a stenosis of 80% or greater with the ECST grading method were 215 cm/second or greater and 90 cm/second or greater, respectively.

CONCLUSIONS

Duplex sonography is a sensitive and accurate tool for evaluating severe carotid stenoses. Optimal PSVs and EDVs vary according to the angiographic method used to grade the stenosis. They are similar for stenoses 70% or greater with the NASCET method and for stenoses 80% or greater with the ECST method.

Diagnostic performance of duplex ultrasonography in the detection of high grade internal carotid artery stenosis

OBJECTIVES

to establish on a national basis whether the diagnostic accuracy of carotid duplex justifies carotid surgery without preoperative angiography.

DESIGN

prospective national multicentre study with 10 participating university and county hospitals.

MATERIAL AND METHODS

one hundred and thirty-four patients, aged 69+/-9 years, were subjected to routine carotid duplex ultrasonography and angiography. The influence of relevant factors on the relation between ultrasonographic and angiographic variables was evaluated using multiple regression analysis. The capacity of carotid ultrasonography to detect internal carotid artery (ICA) stenosis > or =80% was assessed by receiver operating characteristic analysis.

RESULTS

the correlation between peak systolic velocity in ICA (PSV(ICA)) and the angiographic degree of stenosis was strong and significantly influenced only by the applied Doppler angle. Accordingly, the optimal PSV(ICA) cutpoint values for the diagnosis of ICA stenosis > or =80% (ECST method) differed substantially (2.1 and 3.2 m/s) between the two considered angle ranges (0-49 degrees and 50-62 degrees ), the ability to identify high grade ICA stenosis being significantly better at small Doppler angles (0-49 degrees ).

CONCLUSION

ultrasonographic duplex technique identifies high grade ICA stenosis with a high degree of accuracy, which can be further improved by the application of small Doppler angles and the use of angle range specific PSV(ICA) cut-off points.

Acupuncture Improves Peripheral Perfusion in Patients with Reflex Sympathetic Dystrophy

Patients with stage II reflex sympathetic dystrophy syndrome (algodystrophy) often describe a sensation of beneficial warmth in the affected limb when receiving acupuncture treatment. In a case control study of 10 patients with unilateral algodystrophy stage II, and 10 healthy sex and age-matched controls, we investigated whether acupuncture has an effect in blood volume flow and correlated this with a clinical assessment. Blood volume flow was measured by duplex sonography before, during, and after acupuncture. During acupuncture, blood volume flow increased significantly (+31.1%, p (one-tailed) = 0.024) in the patients' effected limbs (by algodystrophy) compared with the patients' untreated limbs (contralateral). It was also elevated compared with the controls' treated limbs (+23.9%, p = 0.046). The corresponding data after acupuncture were +29.5%, p = 0.057 and +38.3%p = 0.014. All but one patient reported improved symptoms. However, only subjective improvement in function, not pain, was positively correlated to the increase in blood volume flow. In patients with algodystrophy stage II, a significant increase of blood volume flow was attributed to acupuncture and was correlated to functional improvement.

Carotid endarterectomy in diabetic patients

OBJECTIVE

The purpose of the current study was to identify the possible short- and long-term effects of diabetes on the outcome of carotid endarterectomy.

METHODS

Medical records were reviewed for 781 carotid endarterectomies (in 734 patients) performed by the same vascular surgeon in a university medical center between January 1994 and December 1998. Patients were divided two groups: those with diabetes (n = 181 patients; 193 operations) and those without diabetes (n = 553; 588 operations). The two groups were similar with respect to mean age, male-female ratio, and contralateral lesions. The only significant differences were a higher prevalence of peripheral vascular disease and dyslipidemia in the diabetic group and a higher prevalence of hemispheric transient ischemic attacks among the nondiabetic patients. Carotid color duplex ultrasound scan had been performed in all patients, and in 56 patients from the diabetic group and 56 patients from the nondiabetic group (matched for age, sex, and contralateral lesions), the distal extension of the lesion from the carotid bifurcation had also been defined. Both of these subgroups were fully representative of their respective groups of origin. Carotid endarterectomy was performed after the induction of general anesthesia; electroencephalographic monitoring was continuous.

RESULTS

Except for the significantly higher prevalence of calcified plaques in the diabetic patients (P <.0001), the characteristics of the carotid disease in the two groups were similar. In the 56-member subgroups, 73.2% of the diabetic and 35.7% of the nondiabetic patients (P <.0001) had lesions extending more than 2 cm beyond the carotid bifurcation. Mean length of plaque beyond the bifurcation was 2.3 +/- 0.09 cm for the diabetic and 1.7 +/- 0.08 cm for the nondiabetic patients (P <.0001). Diabetes was the only factor significantly correlated with plaque length. In the diabetic subgroup, surgery was characterized by significantly longer carotid arteriotomies (P =.03) and clamp times (P <.003). Operative mortality was 1.5% in the diabetic group (2 myocardial infarctions + 1 stroke) and 0.5% in the nondiabetic group (1 myocardial infarction + 2 strokes; P value not significant); stroke rates were 1.5% (3 major strokes) and 0.5% (2 major strokes + 1 minor stroke), respectively (P = not significant). Long-term survival (5 years) was not significantly lower among the diabetic patients.

CONCLUSIONS

Diabetes mellitus does not seem to significantly increase the surgical risk for carotid endarterectomy. The presence of more extensive plaques has no significant effect on the results of surgery.

Assessment of collateral perfusion: a pharmacodynamic study with buflomedil hydrochloride

The aim of the study was to assess the influence of Buflomedil hydrochloride on collateral function. Ten patients with isolated superficial femoral occlusions were investigated twice by duplex sonography with measurement sites at the common femoral artery (CF) and the popliteal artery (PA). After the second scan 200 mg of Buflomedil hydrochloride were infused; the infusion was followed by a third duplex examination. Endpoints assessed included the arterial diameter (D(CF), D(PA)), the systolic peak velocity (Vmax), the mean velocity of the maximum envelope (Vmean m.e.), the intensity weighted time average mean velocity (Vmean i.w.), the maximum reverse flow velocity (Vrev), the end-diastolic velocity (Venddiast), the calculated volume flow (Q), the pulsatility and the resistance indices (PI, RI), and PI and RI based segmental damping factors (DF(PI), DF(RI)). For the CF measurement site the infusion of Buflomedil hydrochloride resulted in a significant reduction in Vrev and PI (p<0.05), whereas trends in the opposite direction (increase) were observed for both measures of Vmean and for Q (0.1<p<0.05). No significant changes were reported for the PA measurement site. DF(PI) numerically decreased (0.1<p<0.05). The pattern of changes suggest that Buflomedil hydrochloride induces collateral vasodilation and thus improves collateral function.

Carotid endarterectomy without angiography does not compromise operative outcome

OBJECTIVES

Carotid angiography is associated with a 2% risk of stroke and, since the advent of colour-duplex ultrasound, its role in the assessment of patients with carotid disease has been the subject of debate. The aim of this study was to evaluate a policy of adopting routine duplex supplemented by selective angiography on operative outcome over a 5-year period.

METHODS

A prospective audit of the results of carotid endarterectomy without routine angiography from January 1992 to December 1996. Angiography was performed only if the ultrasonography was concerned about the distal or proximal extent of disease or to assess subocclusion.

RESULTS

During the study period, 494 carotid endarterectomies were performed but only 35 patients underwent carotid angiography. The indications for angiography were subocclusion/string sign in 22 patients, to assess the limits of proximal or distal disease in 12 and abnormal anatomy in one. During the 5-year study period the overall perioperative death and/or stroke rate was 4.2%. By 1997, the perioperative stroke rate had fallen to 1.3%. In no case in this series was the operation abandoned due to unexpected findings.

CONCLUSION

Although concerns exist about the precise duplex criteria for diagnosing a severe stenosis, this study has shown that a policy of selective angiography does not compromise patient safety or operability and avoids the unnecessary mortality, morbidity and costs associated with routine angiography.

Three-dimensional ultrasound study of carotid arteries before and after endarterectomy; analysis of stenotic lesions and surgical impact on the vessel

BACKGROUND AND PURPOSE

It has been proved that symptomatic patients with severe carotid stenosis benefit from endarterectomy. Currently used methods for quantitation of the severity of carotid stenosis have limitations, and the impact of endarterectomy on the operated region of carotid artery remains unknown. The purpose of this study was to examine the accuracy of a 3-D ultrasound system for quantitation of stenotic lesions and to evaluate changes in regional vessel volume and cross-sectional area after carotid endarterectomy.

METHODS

We studied 14 patients with both carotid angiography and 3-D ultrasound. Of 13 patients who underwent surgery, 12 were reexamined with 3-D ultrasound after surgery. The length and volume of 20 randomly selected plaques were measured from 3-D data sets. The severity of stenosis was quantified by 3-D ultrasound using both a diameter method and an area method on cross-sectional views at the most stenotic site; the results were then compared with those from carotid angiography. The segmental vessel volume and average cross-sectional area of the operated artery both before and after endarterectomy were measured from 3-D ultrasound data.

RESULTS

Good correlation was obtained between 3-D ultrasound and carotid angiography in quantitative analysis of carotid stenosis (SEE=12.4%, r=0.76, and mean difference=7.0+/-12.3% with the diameter method; SEE=10.5%, r=0.82, and mean difference=1.8+/-10.5% with the area method by 3-D ultrasound). 3-D ultrasound had excellent reproducibility and small intraobserver and interobserver variability in plaque length and volume measurements. No significant changes in segmental vessel volume and average cross-sectional area of the operated artery were observed after surgery in patients with suture closure. However, a significant increase in segmental vessel volume was obtained in patients with polyfluorethylene patches applied to the surgical opening of the artery.

CONCLUSIONS

3-D ultrasound can be used for both qualitative and quantitative analysis of plaques in the carotid artery and to detect and quantify significant carotid stenosis. Its volumetric potential has important clinical implications in serial follow-up studies for observing the progression or regression of stenotic lesions and for evaluating the outcome of interventional procedures such as endarterectomy or stent placement.

Cost management strategies for carotid endarterectomy

BACKGROUND

We developed a model for capitation and global pricing for carotid endarterectomy.

METHODS

A care algorithm for diagnosis, perioperative management, and postoperative care using cost data was developed. Perioperative care charges were extrapolated from a 1-year experience and applied to models to determine pricing for a 1-year global fee and a 5-year capitated contract.

RESULTS

Global pricing was estimated at $12,071 per patient while a capitated price for 5-year care was $17,175. Based on the age mix of the population, a per member, per month cost could be calculated assuming a frequency of 414 procedures per 100,000 patients over age 65 and 31 procedures per 100,000 patients under 65. Sources of costs were extensive preoperative diagnostic testing, particularly angiography, brain imaging, and cardiac evaluation.

CONCLUSIONS

Global pricing and capitation are both feasible for carotid endarterectomy. Each approach has unique risks and benefits.