Asymptomatic High-grade Internal Carotid Artery Research Articles

Endarterectomy for asymptomatic high-grade internal carotid artery stenosis—Does age alone really matter?

Abstract Background The aim of this retrospective observational study was to assess whether patients ≥ 75 years of age had a significantly inferior 5-year stroke free survival rate compared to patients Methods All consecutive patients with asymptomatic high-grade internal carotid artery (ICA) stenosis operated on from January 1997 to December 1999. Of 273 consecutive patients with asymptomatic carotid artery stenosis, follow up was complete for 253 patients. Results Of 253 patients, 152 were younger and 102 older than 75 years at surgery (65 ± 8 years (range 43–74) and 79 ± 4 years (range 75–90); P Conclusion Age alone was not a predictor of inferior long-term outcome after carotid endarterectomy for asymptomatic high-grade stenosis. However, patient selection is crucial. If adhered to epidemiological data for risk factors of stroke and death, patients with a mean age of ≥ 75 years can be treated safely with acceptable long-term results. In the analyzed population older patients with a contralateral symptomatic carotid territory have a significantly inferior 5-year ipsilateral stroke free survival compared to patients

T2-Imaging to Assess Cerebral Oxygen Extraction Fraction in Carotid Occlusive Disease: Influence of Cerebral Autoregulation and Cerebral Blood Volume.

PurposeQuantitative T2'-mapping detects regional changes of the relation of oxygenated and deoxygenated hemoglobin (Hb) by using their different magnetic properties in gradient echo imaging and might therefore be a surrogate marker of increased oxygen extraction fraction (OEF) in cerebral hypoperfusion. Since elevations of cerebral blood volume (CBV) with consecutive accumulation of Hb might also increase the fraction of deoxygenated Hb and, through this, decrease the T2’-values in these patients we evaluated the relationship between T2’-values and CBV in patients with unilateral high-grade large-artery stenosis.Materials and MethodsData from 16 patients (13 male, 3 female; mean age 53 years) with unilateral symptomatic or asymptomatic high-grade internal carotid artery (ICA) or middle cerebral artery (MCA) stenosis/occlusion were analyzed. MRI included perfusion-weighted imaging and high-resolution T2’-mapping. Representative relative (r)CBV-values were analyzed in areas of decreased T2’ with different degrees of perfusion delay and compared to corresponding contralateral areas.ResultsNo significant elevations in cerebral rCBV were detected within areas with significantly decreased T2’-values. In contrast, rCBV was significantly decreased (p<0.05) in regions with severe perfusion delay and decreased T2’. Furthermore, no significant correlation between T2’- and rCBV-values was found.ConclusionsrCBV is not significantly increased in areas of decreased T2’ and in areas of restricted perfusion in patients with unilateral high-grade stenosis. Therefore, T2’ should only be influenced by changes of oxygen metabolism, regarding our patient collective especially by an increase of the OEF. T2’-mapping is suitable to detect altered oxygen consumption in chronic cerebrovascular disease.

Abstract 15788: Percutaneous and Surgical Carotid Artery Revascularization in Patients With Moderate and Severe (Stage 3 and 4) Chronic Kidney Disease: Insights of the Healthcare Cost and Utilization Project’s National Inpatient Sample

Background: Carotid artery stenting (CAS) has evolved into an alternative modality for the treatment of symptomatic and asymptomatic high-grade internal carotid artery stenosis, particularly in patients considered to be at a high surgical risk for carotid endarterectomy (CEA). Hypothesis: There is limited data on the outcomes of patients with moderate and severe chronic kidney disease (CKD) (GFR=15-59 mL/min/1.73m 2 ) (Stage 3 and 4) undergoing CEA or CAS. Methods: The Healthcare Cost and Utilization Project’s National Inpatient Sample was screened for hospital admissions of patients undergoing CAS and CEA from 2003-2012. Clinical characteristics and outcomes were identified in patients with stage 3 and 4 CKD. The primary outcome of interest was in-hospital major adverse cardiac and cerebrovascular events (MACCE) defined as the composite of in-hospital death, acute myocardial infarction (AMI) and acute cerebrovascular accident (CVA). Results: Our study population consisted of 3,608 patients that underwent CEA and 746 patients that underwent CAS. Patients undergoing CAS had significantly higher rates of coronary artery disease and peripheral vascular disease with similar rates of hypertension, diabetes and hyperlipidemia. There was a higher rate of in-hospital MACCE in patients undergoing CAS compared with patients that underwent CEA, mainly driven by a higher rate of in-hospital strokes (Fig. 1). AMI and mortality rates were similar in both groups. In a multivariable analysis, CAS (OR 1.52, 95% CI 1.25-1.84) was independently predictive of MACCE. Conclusions: In patients with moderate and severe CKD, CAS was associated with similar rates of in-hospital mortality and AMI rates but higher rates of stroke when compared with CEA.

Quantitative High-Field Diffusion Tensor Imaging of Cerebral White Matter in Asymptomatic High-Grade Internal Carotid Artery Stenosis

Background: Recently, several studies using diffusion-sensitized MRI reported changes in patients with high-grade internal carotid artery stenosis (ICAS) suggestive of subtle brain tissue damage. We used diffusion tensor imaging (DTI) to investigate the microstructural cerebral white matter integrity in asymptomatic patients with high-grade ICAS. Methods: In 15 asymptomatic patients with unilateral high grade (>70%) ICAS, we used 3T MRI including DTI. We used a region-of-interest approach comparing quantitative DTI metrics between both hemispheres including the so-called border zones. MR images were also assessed for periventricular white matter lesions (PWML) as well as collaterals via the circle of Willis. Results: There was no significant intraindividual difference of fractional anisotropy or mean diffusivity values between the hemispheres for any region. PWML was graded 0° in 6 patients, I° in 9 and II° in 2. Conclusions: In clinically asymptomatic patients with high-grade unilateral ICAS, there was no difference between the DTI parameters of the affected and the unaffected hemisphere. These findings contrast with other studies in asymptomatic high-grade ICAS, which is likely due to patient selection. These findings argue against concomitant chronic tissue integrity changes and implicate the benignity of asymptomatic carotid artery disease in individual patients.

N-terminal pro B-type natriuretic peptide (NT pro-BNP) is a predictor of long-term survival in male patients of 75 years and older with high-grade asymptomatic internal carotid artery stenosis

Carotid endarterectomy (CEA) is commonly performed for asymptomatic high-grade internal carotid artery (ICA) stenosis to prevent stroke. However, despite advancing age of the society, for patients older than 75 years, there is no recommendation by the European guidelines for CEA, as this age group might not benefit from this intervention due to a limited life expectancy. We assessed N-terminal pro B-type natriuretic peptide (NT pro-BNP) as a predictive marker for long-term survival in this particular patient population in order to stratify patients for an improved surgical outcome. In a nonrandomized single-center clinical trial, we prospectively studied mortality rates of 205 consecutive patients (80 women, 125 men; mean age, 75 ± 10 years) with asymptomatic high-grade ICA stenosis in relation to preoperative plasma NT pro-BNP levels. We estimated cumulative survival over 5 years by Kaplan-Meier curves and established a proportional hazard-model by Cox regression. In male patients, higher levels of preoperative NT pro-BNP levels were associated with a significantly increased long-term mortality. Those 75 years or older had the same survival rate as younger patients, if NT pro-BNP levels were low, making them thus eligible for CEA. The results of our study suggest that preoperative plasma levels of NT pro-BNP are a valuable tool for the stratification of male patients. Male patients older than 75 years with low levels of NT pro-BNP should be referred for carotid revascularization, as they will most likely enjoy the benefit of surgery.

The Value of the Serum Neurofilament Protein Heavy Chain as a Biomarker for Peri-operative Brain Injury After Carotid Endarterectomy

This prospective study examined the value of serum neurofilament protein levels for detecting peri-operative brain damage following carotid endarterectomy. An ELISA was used for quantification of neurofilament protein heavy chain (NfH(SMI35)) levels from patients undergoing endarterectomy for symptomatic (n = 17) and asymptomatic high-grade internal carotid artery stenosis (n = 30). All patients underwent diffusion-weighted brain imaging before and after the procedure. NfH(SMI35) levels were significantly higher in patients with a symptomatic carotid artery stenosis (0.131 ng/ml) if compared to asymptomatic patients (0.055 ng/ml, P = 0.01). However, serum NfH(SMI35) levels were not related to signs of brain ischemia on routine brain imaging techniques. Our pilot data suggests that raised NfH(SMI35) serum levels in patients with symptomatic carotid artery disease may be a sensitive biomarker for diffuse ischemic damage to the CNS. We conclude that NfH(SMI35) failed to qualify as a biomarker for peri-operative brain injury in CEA and factors that may have compromised the validation of this biomarker are discussed and need to be taken into account for the design of further studies.

Chlamydia pneumoniae, Herpes simplex virus and Cytomegalovirus in symptomatic and asymptomatic high-grade internal carotid artery stenosis. Does infection influence plaque stability?

Current debates are focused on inflammatory processes in atherosclerotic lesions as a possible pathomechanism for destabilization and thrombembolism. In this prospective study the role of systemic and local infection in patients with high-grade internal carotid artery stenosis (ICA) was evaluated. Serum antibody titers of 109 consecutive patients, who underwent surgery for ICA stenosis (asymptomatic n = 40, symptomatic n = 69) were prospectively measured for Chlamydia pneumoniae (Cpn) (IgA and IgG), Herpes simplex virus (HSV) (IgG, IgM) and Cytomegalovirus (CMV) (IgG, IgM) respectively. 53 carotis plaques of this group (asymptomatic n = 17, symptomatic n = 36) could be analyzed by polymerase chain reaction (PCR) for Cpn-, HSV- and CMV-DNA presence. Seropositivity was found in 61,5% for Cpn, 91,7% for HSV and 72,5% CMV respectively. No significant relation was found between symptomatic and asymptomatic patients as well as no difference was seen for presence of IgA antibodies against Cpn comparing both groups. Plaque-PCR revealed Cpn in 7 cases (13,2%), HSV in 2 cases (3,8%) and no CMV had been detected. Again, no significant relationship was found concerning symptomatic and asymptomatic patients. All 9 PCR-positive plaques displayed lesions of "complicated atherosclerosis" as central fibrous necrosis and calcification or plaque bleeding and surface thrombosis. Our results do not support the hypothesis that systemic Cpn, HSV or CMV- infection or evidence of Cpn-, HSV- or CMV-DNA in carotid plaques causes plaque destabilization and cerebral thromboembolism. Plaque infection could only be observed in cases with advanced atherosclerosis.

Geographical inequality in the provision of carotid endarterectomy in Scotland. Scottish Vascular Audit Group.

Carotid endarterectomy (CEA) is a proven method of stroke prevention in patients with symptomatic and asymptomatic high-grade internal carotid artery stenosis. This study examined whether site of residence affects access to CEA in Scotland. Scottish Morbidity Record hospital discharge data were collected by the Information and Statistics Division of the National Health Service in Scotland and analysed for the interval 1 January 1989 to 31 December 1995. The number of CEAs performed in the hospitals of each of the 15 regional Health Boards, and CEA rate per 100000 population resident in each Health Board region, were determined. In 1989, 65 CEAs were performed in the hospitals of five Health Boards and in 1995, 431 CEAs were performed in nine Health Boards. In 1989, the CEA rate per 100000 resident population varied between 0 (four regions) and 4 (one region), with one region significantly different from Scotland as a whole (P<0.001). In 1995, the CEA rate varied between 0 (two regions) and 19 (one region), with two regions significantly different from Scotland as a whole (P< 0.01). Despite a sixfold increase in the number of CEAs being performed, and a rise in the number of centres performing CEA, there is increasing geographical inequality in the provision of CEA in Scotland.

B-mode Ultrasound Imaging in Symptomatic Internal Carotid Artery Stenosis: Correlation with Clinical and Operative Findings

B-mode ultrasound (duplex) imaging is a technique that enables the evaluation of plaque characteristics. The purpose of this study was to determine the accuracy and usefulness of duplex imaging by comparing a relationship between the preoperative clinical neurologic status, preoperative duplex findings, and operative findings in patients who had carotid endarterectomy (CEA) for symptomatic high-grade internal carotid artery (ICA) stenosis. Sixty patients with symptomatic ICA stenosis who underwent CEA from September 1995 to August 1998 were included in this study. Plaque morphology was categorized in terms of echogenicity by preoperative duplex imaging. A correlation between the frequency of preoperative ischemic stroke and duplex and operative findings was prospectively evaluated. Thirty-eight patients had recent and multiple cerebral ischemia, and 22 experienced a single episode more than 1 month before CEA. Recent and multiple events occurred in 24 (72.7%) of 33 patients with echolucent plaques, but only 6 (40.0%) of 15 with echogenic plaques (p&lt;0.05). Thirty-six (75%) of 48 patients with soft plaques by operative findings had recent and multiple events, but only two (16.7%) of 12 with calcified plaques experienced recent and multiple events (p&lt;0.01). Overall sensitivity, specificity, and accuracy of duplex imaging were 79.5%, 77.8%, and 79.2%, respectively. Duplex imaging is reliable in determining ICA plaque characteristics. Recent and multiple cerebral ischemia occurred more frequently in patients with echolucent plaques by preoperative duplex and soft plaques by operative findings. The presence of echolucent plaque may be used as a strong indication for CEA in patients who have asymptomatic high-grade ICA stenosis.

Cerebral microembolism and the risk of ischemia in asymptomatic high-grade internal carotid artery stenosis.

Previous work has shown that cerebral microembolism detected with transcranial Doppler sonography distal to internal carotid artery stenosis occurs more frequently in recently symptomatic compared with asymptomatic patients. It has remained unclear whether cerebral microembolism also indicates a higher risk of future cerebral or retinal ischemia. Sixty-four asymptomatic patients with unilateral 70% to 90% internal carotid artery stenosis were investigated prospectively (mean follow-up, 72 weeks). Five patients developed ischemic symptoms attributable to the stenosis (transient ischemic attack, 2 patients; stroke, 3 patients). A microembolic rate of > or = 2 per hour in the ipsilateral middle cerebral artery was associated with a substantially increased risk of developing ischemia of the corresponding carotid territory (odds ratio, 31; 95% confidence interval, 3 to 302; P = .005). This prospective pilot study suggests that cerebral microembolism detected with transcranial Doppler sonography may define a high-risk subgroup among patients with asymptomatic high-grade internal carotid artery stenosis.

Asymptomatic high-grade internal carotid artery stenosis: Is stratification according to risk factors or duplex spectral analysis possible?

High-grade (80% to 99% diameter reduction) asymptomatic internal carotid artery stenoses are associated with an increased neurologic event rate (transient ischemic attack, stroke, asymptomatic internal carotid artery occlusion) compared to less severe asymptomatic lesions. However, many do remain free of associated events. To determine which are most dangerous, we compared risk factors and duplex scan results in two groups with asymptomatic high-grade internal carotid artery stenoses. Group A included 31 patients with 33 unoperated high-grade lesions that remained asymptomatic for at least 12 months (mean 30 months). Group B included 25 patients with 26 initially asymptomatic lesions that subsequently were associated with a neurologic event (mean time to event 7.4 months). The groups did not differ significantly in average age, sex, aspirin use, smoking, or prevalence of hypertension, diabetes, or cardiac disease. With respect to the index high-grade lesion, there was no difference in the frequency of a >50% contralateral internal carotid artery stenosis or >50% ipsilateral external carotid stenosis. However, on duplex scanning, high-grade stenoses with >6.5 kHz end-diastolic frequencies were more frequently associated with an event than high-grade lesions with lower end-diastolic frequency (p = 0.0004). Similarly, seven of 23 lesions (30%) with end-diastolic frequency >6.0 kHz were associated with subsequent internal carotid artery occlusion compared to only one of 29 (3.5%) with end-diastolic frequency ≤6.0 kHz (p = 0.025). Analysis of internal carotid artery end-diastolic frequency may help select a subgroup of patients with asymptomatic high-grade lesions who are at greatest risk for subsequent neurologic symptoms or ICA occlusion or both.

Asymptomatic high-grade internal carotid artery stenosis: is stratification according to risk factors or duplex spectral analysis possible?

High-grade (80% to 99% diameter reduction) asymptomatic internal carotid artery stenoses are associated with an increased neurologic event rate (transient ischemic attack, stroke, asymptomatic internal carotid artery occlusion) compared to less severe asymptomatic lesions. However, many do remain free of associated events. To determine which are most dangerous, we compared risk factors and duplex scan results in two groups with asymptomatic high-grade internal carotid artery stenoses. Group A included 31 patients with 33 unoperated high-grade lesions that remained asymptomatic for at least 12 months (mean 30 months). Group B included 25 patients with 26 initially asymptomatic lesions that subsequently were associated with a neurologic event (mean time to event 7.4 months). The groups did not differ significantly in average age, sex, aspirin use, smoking, or prevalence of hypertension, diabetes, or cardiac disease. With respect to the index high-grade lesion, there was no difference in the frequency of a greater than 50% contralateral internal carotid artery stenosis or greater than 50% ipsilateral external carotid stenosis. However, on duplex scanning, high-grade stenoses with greater than 6.5 kHz end-diastolic frequencies were more frequently associated with an event than high-grade lesions with lower end-diastolic frequency (p = 0.0004). Similarly, seven of 23 lesions (30%) with end-diastolic frequency greater than 6.0 kHz were associated with subsequent internal carotid artery occlusion compared to only one of 29 (3.5%) with end-diastolic frequency less than or equal to 6.0 kHz (p = 0.025). Analysis of internal carotid artery end-diastolic frequency may help select a subgroup of patients with asymptomatic high-grade lesions who are at greatest risk for subsequent neurologic symptoms or ICA occlusion or both.