Home About us Contact
|
Home About us Contact | ||
|
|
||
Internal Carotid Artery Stenosis (internal + carotid_artery_stenosis)
Selected AbstractsIs Transcranial Doppler Ultrasound Undervalued for Detection of Intracranial Internal Carotid Artery Stenosis?JOURNAL OF NEUROIMAGING, Issue 3 2010Gustavo J. Rodriguez MD No abstract is available for this article. [source] A Broad Diagnostic Battery for Bedside Transcranial Doppler to Detect Flow Changes With Internal Carotid Artery Stenosis or OcclusionJOURNAL OF NEUROIMAGING, Issue 3 2001Ioannis Christou MD ABSTRACT Background and Purpose. The authors establish accuracy parameters of a broad diagnostic battery for bedside transcranial Doppler (TCD) to detect flow changes due to internal carotid artery (ICA) stenosis or occlusion. Methods. The authors prospectively studied consecutive patients with stroke or transient ischemic attack referred for TCD. TCD was performed and interpreted at bedside using a standard insonation protocol. A broad diagnostic battery included major criteria: collateral flow signals, abnormal siphon or terminal carotid signals, and delayed systolic flow acceleration in the middle cerebral artery. Minor criteria included a unilateral decrease in pulsatility index (, 0.6 or , 70% of contralateral side), flow diversion signs, and compensatory velocity increase. Angiography or carotid duplex ultrasound (CDU) was used to grade the degree of carotid stenosis using North American criteria. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of TCD findings were determined. Results. Seven hundred and twenty patients underwent TCD, of whom 517 (256 men and 261 women) had angiography and/or CDU within 8.8 ± 0.9 days. Age was 63.1 ± 15.7 years. For a 70% to 99% carotid stenosis or occlusion, TCD had sensitivity of 79.4%, specificity of 86.2%, PPV of 57.0%, NPV of 94.8%, and accuracy of 84.7%. For a 50% to 99% carotid stenosis or occlusion, TCD had sensitivity of 67.5%, specificity of 83.9%, PPV of 54.5%, NPV of 90.0%, and accuracy of 81.6%. TCD detected intracranial carotid lesions with 84.9% accuracy and extracranial carotid lesions with 84.4% accuracy (sensitivity of 88% and 79%, specificity of 85% and 86%, PPV of 24% and 54%, and NPV of 99% and 95%, respectively). The prevalence of the ophthalmic artery flow reversal was 36.4% in patients with , 70% stenosis or occlusion. If present, this finding indicated a proximal ICA lesion location in 97% of these patients. Conclusions. In symptomatic patients, bedside TCD can accurately detect flow changes consistent with hemodynamically significant ICA obstruction; however, TCD should not be a substitute for direct carotid evaluation. Because TCD is sensitive and specific for , 70% carotid stenosis or occlusion in both extracranial and intracranial carotid segments, it can be used as a complementary test to refine other imaging findings and detect tandem lesions. [source] Prevalence of and risk factors for extracranial internal carotid artery stenosis in Korean Type 2 diabetic patientsDIABETIC MEDICINE, Issue 12 2006J. H. Park Abstract Aims The objectives of this study were to evaluate the prevalence of and risk factors for extracranial internal carotid artery stenosis in Type 2 diabetic patients. Methods This study included 406 patients aged 40,79 years with Type 2 diabetes (male 55.4%, female 44.6%). Both carotid arteries of each patient were examined by carotid duplex scanning. The duplex ultrasound criteria based on the North American Symptomatic Carotid Endarterectomy Trial (NASCET) measurement method were used for the identification of carotid stenosis. Results Extracranial internal carotid artery stenosis , 40% by velocity criteria was detected in 5.2% of the patients. The prevalence of carotid stenosis increased with advancing age: 1.0% at 40,49 years of age, 5.0% at 50,59 years, 7.3% at 60,69 years and 9.5% at 70,79 years. The degree of stenosis was > 70% in 42.9% of patients with stenosis, Bilateral stenosis was detected in 14% of patients. Of the patients with , 40% carotid stenosis, 33% had a decreased ankle-brachial index, 38% had a previous history of stroke, and only one patient (5%) had a documented history of coronary artery disease. Multivariate analysis, including variables determined to be significantly different by univariate analysis between patients with or without , 40% stenosis, indicated that age, systolic blood pressure and high-density lipoprotein (HDL)-cholesterol (inverse correlation) were independent risk factors associated with carotid stenosis. Conclusions Carotid duplex scanning is a useful strategy in identifying carotid stenosis in older Type 2 diabetic patients with high systolic blood pressure, or low levels of HDL cholesterol. The early identification and subsequent appropriate management of carotid stenosis, particularly in this group of patients, may facilitate efforts to reduce the incidence of macrovascular complications. [source] Cerebral vasomotor reactivity of bilateral severe carotid stenosis: is stroke unavoidable?EUROPEAN JOURNAL OF NEUROLOGY, Issue 2 2006A. Y. Gur We evaluated the cerebral hemodynamic features of severe bilateral carotid stenosis by assessing and comparing cerebral vasomotor reactivity (VMR) in the middle cerebral (MCA) and vertebral arteries (VA) by transcranial Doppler and the Diamox (1 g acetazolamide i.v.) test. VMR was evaluated by recording the percentage differences in peak systolic blood flow velocity in each MCA and VA at baseline and by the Diamox test. Twenty-eight symptomatic (SCAS) and 31 asymptomatic (ACAS) patients with bilateral severe (>70%) internal carotid artery stenosis were studied. The mean MCA VMR% was 29 ± 26.9% in SCAS and 43.2 ± 26.8% in ACAS patients (P < 0.01). Their respective mean VA VMR% was 30.2 ± 36.5% and 39.6 ± 24.4% (P = NS). VMR% of the symptomatic MCA side in SCAS patients was significantly lower than the opposite side (20.5 ± 31.1% and 39.2 ± 37.9% respectively; P < 0.03). In contrast, the VA VMR% of both sides in SCAS patients remained similar (28.1 ± 39.3% and 34.6 ± 47.9% respectively; P = NS). VMR% of the MCA and VA in ACAS patients was also similar for both sides of bilateral carotid stenosis. The cerebral hemodynamic features differ between SCAS and ACAS patients with bilateral carotid occlusive disease in the anterior part of the circle of Willis. An independent cerebral vascular reserve capacity of the posterior circulation is proposed. [source] Role of hyperlipidemia in atherosclerotic plaque formation in the internal carotid arteryJOURNAL OF CLINICAL ULTRASOUND, Issue 6 2006Levente Kerenyi MD Abstract Purpose. The role of hyperlipidemia in atherosclerotic changes of the carotid artery is controversial. The aims of this retrospective study were to assess (1) the relationship between total serum cholesterol and triglyceride and the grade of internal carotid artery stenosis and (2) whether total serum cholesterol and triglyceride levels are independent risk factors for internal carotid artery atherosclerosis. Methods. The files of 1,934 acute ischemic stroke patients were investigated retrospectively. The atherosclerotic involvement of the internal carotid artery was assessed via duplex sonography as percent of stenosis and was graded as follows: group 1, no plaque; group 2, <30% stenosis; group 3, 30,99% stenosis; and group 4, occlusion. Results. The mean age of the patients was 66.9 ± 12.8 years. Patients without any plaque had significantly lower cholesterol levels compared with those with any degree of internal carotid artery stenosis. Univariate analysis revealed that age (p < 0.001), sex (p < 0.001), hypertension (p < 0.05), cholesterol (p < 0.01), triglycerides(p < 0.05), and smoking (p < 0.001) were significant contributors to atherosclerosis. In the ordinal logistic regression model, age (p < 0.001), sex (p < 0.001), smoking(p < 0.001), and cholesterol (p < 0.05) remained independent predictors of internal carotid artery atherosclerosis. Conclusions. Total serum cholesterol level seems to be an independent risk factor of atherosclerosis in the carotid artery. © 2006 Wiley Periodicals, Inc. J Clin Ultrasound 34:283,288, 2006 [source] Echocardiographic Findings of Patients With Retinal Ischemia or EmbolismJOURNAL OF NEUROIMAGING, Issue 3 2002Mikael Mouradian MD ABSTRACT Background and Purpose. A potential source of emboli is not detected in more than 50% of patients with retinal arterial occlusive events. Echocardiographic studies are not always included in the diagnostic workup of these patients. The authors studied the diagnostic yield of transthoracic (TTE) and/or transesophageal (TEE) echocardiography in identifying potential sources of emboli in patients with retinal ischemia or embolism. Methods. In a prospective study, 73 consecutive patients with clinically diagnosed retinal ischemia or embolism received a standardized diagnostic workup including retinal photography, echocardiography, and imaging studies of the internal carotid arteries. TTE was performed in 83.6% of patients, TEE was performed in 5.5% of patients, and both TTE and TEE were per-formed in 11.0% of patients. Ophthalmological diagnoses consisted of amaurosis fugax (n= 28), asymptomatic cholesterol embolism to the retina (n= 34), and branch or central retinal artery occlusion (n= 11). Results. Echocardiography identified a potential cardiac or proximal aortic source for embolism in 16 of 73 (21.9%) patients, including 8 who also had either atrial fibrillation or internal carotid artery stenosis of more than 50% on the side of interest. Thus, 8 of 73 (11.0%) patients had lesions detected only by echocardiography. The most commonly identified lesions were proximal aortic plaque of more than 4 mm thickness (n= 7, 9.6%) and left ventricular ejection fraction of less than 30% (n= 6, 8.2%). TEE was particularly helpful in identifying prominent aortic plaques. Conclusion. Echocardiography frequently identifies lesions of the heart or aortic arch that can act as potential sources for retinal ischemia or embolism. Further studies are needed to evaluate the prognostic and therapeutic relevance of these findings. [source] Association of carotid artery atheromatous plaque types with cerebral perfusionANZ JOURNAL OF SURGERY, Issue 11 2009Dong Yan Gao Abstract Background:, In an attempt to define the association of internal carotid artery atheromatous plaque morphology with potential cerebral ischaemia, we have investigated the relationship of different carotid plaque types with defects in cerebral perfusion. Methods:, In 130 patients requiring surgical correction of internal carotid artery stenoses greater than 70%, defects in cerebral perfusion due to both haemodynamic insufficiency and intracerebral vessel occlusion were identified using single photon emission computed tomography scans (SPECT). Carotid artery plaques in these patients were classified as homogeneous or heterogeneous based on preoperative Doppler Duplex Scanning and on the macroscopic characteristics of the plaques recorded by the surgeon during carotid endarterectomy, with sub-classification into potentially embolus-generating and non- embolus-generating plaques. In individual patients, plaque types were then correlated with the perfusion defects found in the SPECT scans. Results:, Of 130 patients, 112 (86%) had cerebral perfusion defects. In 56 asymptomatic patients in the study, 48 (85.7%) had perfusion defects as did 64 (86.5%) of 74 symptomatic patients. Cerebral infarcts were seen in 41 (31.5%). Occlusive infarcts (66%) were twice as frequent as haemodynamic insufficiency infarcts (34%). Eighteen patients with small cerebral infarcts on SPECT scanning gave no medical history of cerebral symptoms. Statistical analysis of the results revealed that there was no statistically identifiable association between carotid plaque type and the generation of cerebral symptoms or infarction. Conclusion:, This study found that internal carotid plaque morphology has no statistically significant association with perfusion defects, symptoms or cerebral infarction in patients with significant internal carotid artery stenosis. Also, it is suggested that haemodynamic cerebral infarction may be more common that previously believed (34% of infarcts identified in the study). Further, it is suggested that plaque morphology alone is not an indication for carotid endarterectomy. [source] Why do some patients with > 80% stenosis of the internal carotid artery not undergo surgery?ANZ JOURNAL OF SURGERY, Issue 11 2001A retrospective review Background: Carotid endarterectomy is known to benefit both symptomatic and asymptomatic patients with high-grade internal carotid artery stenosis. Duplex scanning is the ,gold standard' for non-invasive preoperative investigation of carotid artery stenosis. The aim of the present study was to analyse the indications for duplex scanning and to identify other factors that influenced the management of patients with high-grade stenosis who did not undergo carotid endarterectomy. Methods: A total of 271 patients was observed to have > 80% stenosis of the internal carotid artery on duplex scanning during the period of review. Of these patients, 85 did not undergo carotid endarterectomy. The vascular laboratory database and hospital records of these patients were retrospectively reviewed. Results: The indications for requesting a carotid duplex scan in the 85 patients were transient ischaemic attack (22%), stroke (25%), symptomatic bruit (7%), asymptomatic bruit (12%), and stroke and symptomatic bruit combined (7%). Falls and preoperative carotid assessment prior to coronary surgery were the commonest indications in the remaining patients. The main risk factors were cardiac (68%), hypertension (60%), respiratory (21%), diabetes (25%), peripheral vascular disease (19%), neoplasm (16%) and renal disease (16%). Twenty-five per cent of the patients were over 80 years of age. Conclusion: In the present study risk factors associated with increased perioperative morbidity and mortality were the commonest explanation for patients with high-grade stenosis of the internal carotid artery not undergoing surgery. These patients would generally not meet the inclusion criteria for the major carotid endarterectomy trials. [source] Association between intraplaque haemorrhage in the carotid atherosclerotic lesion, the degree of internal carotid artery stenosis and timing of ischaemic neurological eventsBRITISH JOURNAL OF SURGERY (NOW INCLUDES EUROPEAN JOURNAL OF SURGERY), Issue 4 2001R. Mofidi Background: Expansion of carotid atherosclerotic plaques as a result of intraplaque haemorrhage has been implicated in the development of ischaemic neurological events. The relationship between the quantity of haemorrhage in the dominant atherosclerotic lesion, the degree of internal carotid artery (ICA) stenosis and the chronology of patients' symptoms was examined. Methods: Consecutive patients undergoing carotid endarterectomy were included. The nature and timing of symptoms were recorded. Aortic arch injection digital subtraction angiography was performed before operation. Carotid endarterectomy specimens were serially sectioned and examined histologically. The amount of intraplaque haemorrhage was measured with digital image analysis. The influence of timing of symptoms on the quantity of intraplaque haemorrhage was compared with Kaplan,Meier analysis. Correlation between degree of ICA stenosis and quantity of intraplaque haemorrhage was assessed by means of regression analysis. Results: Seventy-four patients (20 asymptomatic, 54 symptomatic) were included. The median latency of symptoms was 28 (1,600) days. Intraplaque haemorrhage was common: 54 (73 per cent) of 74 patients. Mean(s.e.m.) cumulative symptom-free survival before operation for patients with no intraplaque haemorrhage was 0·71(0·11), compared with 0·58(0·11) in those exhibiting haemorrhage in less than 50 per cent of the plaque area, and 0·20(0·07) in lesions with over 50 per cent (P = 0·002). A close correlation was observed between the degree of ICA stenosis and haemorrhagic content of the dominant atherosclerotic lesion (r2 = 0·433, P < 0·001). Conclusion: These results confirm the association between intraplaque haemorrhage and the degree of ICA stenosis. They further demonstrate an association between the size of haemorrhage and timing of neurological events, suggesting a causative role for intraplaque haemorrhage in the development of ischaemic neurological events. © 2001 British Journal of Surgery Society Ltd [source] | ||||||||||||||||||||||