Measuring carotid artery stenosis

OBJECTIVE: Five different calliper methods for assessing the degree of carotid artery stenosis and visual estimation ("eyeballing") of postmortem carotid arteriograms were compared with the planimetric gold standard of the area reduction at the site of the stenosis. METHODS: During autopsy 53 carotid specimens were removed in toto from 31 neurological patients. Carotid arteries were ligated and redistended to a physiological degree for standardised three-plane arteriography. Afterwards, the entire specimen was filled with an embedding medium under the same conditions and sectioned. Slices at the site of stenoses were histologically processed. Computerised planimetric analysis of the lumen area reduction was performed and compared with the arteriographic findings. Arteriograms were evaluated by two independent observers by means of linear Common Carotid Artery (CC), the European Carotid Surgery Trial (ECST) and the North American Symptomatic Carotid Endarterectomy Trial (NASCET), and squared measurements (NASCET2, ECST2) after applying the pi r2 function. Further, three independent observers performed eyeballing of the degree of stenosis from the postmortem arteriographies. RESULTS: Planimetry was carried out in 29 internal carotid artery (ICA) and 17 common carotid artery (CCA) stenoses ranging from 8.5 to 100%. The smallest mean differences of the degree of stenosis in % between planimetry and arteriography were -0.5 and 0.6%. The narrowest 95 %-limits of agreement covered a range of +/-24.1 and 26.3% of stenoses, and the highest correlation coefficients were both 0.9 for the CC and ECST2 techniques, respectively. By eyeballing, the degree of stenosis was underestimated by 13.5 to 15.8% on average. The narrowest limits of agreement between two observers for eyeballing covered a range of 35%. CONCLUSION: Three-plane arteriography has only a moderate accuracy and reproducibility in detecting and measuring carotid artery stenosis independent of the technique of measurement used.     

Prediction of angiographic carotid artery stenosis indexes by colour Doppler-assisted duplex imaging. A critical appraisal of the parameters used

The aim of our study was to establish colour Doppler-assisted duplex imaging (CDDI)-criteria to predict an angiographic internal carotid artery (ICA) stenosis of at least 70%, according to the North American Symptomatic Carotid Endarterectomy Trial (NASCET) and European Carotid Surgery Trialists (ECST) methods of measurement. In the following, we describe the findings in 79 patients who were screened for carotid endarterectomy by CDDI and further evaluated by digital subtraction angiography (DSA). In 158 carotid arteries, 107 stenoses of > 30% and nine occlusions were found. Receiver operator characteristic graphs were constructed in order to calculate sensitivities and specificities of the assessment by CDDI in the prediction of high-grade stenoses determined by angiography. Optimal cut-off points were defined by highest accuracy which reflects the combination of high sensitivity and specificity. The critical index of a high-grade ICA stenosis according to the ECST method could be predicted with an accuracy greater than 90% by a systolic peak velocitiy of 1.25 m/s or an area reduction by CDDI of 70%. Corresponding values, 1.6 m/s and 80% area reduction, predicted the stenosis indexes according to the NASCET method less reliably, with accuracies of between 80% and 90%. Flow velocity criterion was slightly less accurate than the area reduction criterion by CDDI. Finally, double-blind evaluation performed by two readers per examination modality showed that the measurement of area reduction in CDDI is at least as reliable as stenosis indexes according to ECST and NASCET methods.     

Carotid endarterectomy: Trials and tribulations

Since its introduction 40 years ago, the value of carotid endarterectomy has been controversial. In the early 1980s, several clinical trials were initiated to determine the efficacy of this operation in patients with carotid stenoses who were either symptomatic or asymptomatic for retinal or hemispheric ischemia. In 1991, interim results were published for the North American Symptomatic Carotid Endarterectomy Trial (NASCET) and the European Carotid Surgery Trial (ECST), both reporting efficacy for surgery in patients with symptomatic carotid artery stenosis of greater than 70%. Subgroup analyses revealed variable risk groups. The Veterans Administration (VA) Symptomatic Trial (Cooperative Studies Program 309 of the Department of Veterans Affairs) terminated early because of these results and its findings were consistent with the results of the larger trials. NASCET and ECST continue for symptomatic patients with carotid stenoses between 30% and 69%. The results of three trials in asymptomatic patients, the Mayo asymptomatic trial, the Carotid Artery Stenosis with Asymptomatic Narrowing: Operation Versus Aspirin trial, and the VA Asymptomatic Trial (Cooperative Studies Protocol 167 of the Department of Veterans Affairs), have been reported. None showed a statistically significant benefit for surgery in the prevention of stroke or death. However, none was sufficiently large to exclude such a benefit. The large Asymptomatic Carotid Atherosclerosis Study is in progress. Differences in the results and design of these trials are discussed as are restrictions in the applicability of their results.     

Accurate Measurement of Carotid Stenosis

The methods used for measurement of carotid artery stenosis are not uniform. Witness the chaos that developed when the North American Symptomatic Carotid Endarterectomy Trial (NASCET) group changed its classification system from area to linear measurements only to discover that the European Carotid Stenosis Trial (ECST) used still another angiographic definition of degree of stenosis so that the data from the two studies were not comparable. Fortunately, this has been reconciled by recalculation of the data. In still other studies, using unvalidated ultrasound instruments has made it difficult or impossible to compare results. In part, these problems have been the result of misdirected attempts to amalgamate concepts from Doppler and duplex ultrasound with those of arteriography. The former is more precise and accurate than the latter, yet its methodology is harder to apply and has not been generally distributed. Even such anatomical terms as “carotid bulb” are not standard. Ultrasonographers consider it to be the distal common carotid artery, to vascular surgeons it is the carotid sinus, while still others consider it to be both or neither. The present authors advocate a uniform methodology utilizing duplex ultrasound and predict that it plus magnetic resonance angiography will become the standard by which extracranial carotid artery disease is evaluated in the     

颈动脉闭塞性疾病外科治疗发展史简

本文简单回顾了颈动脉闭塞性疾病的外科治疗历史。特别指出,自1991年北美症状性颈动脉内膜切除术试验和欧洲颈动脉外科手术试验等多中心大规模随机对照临床试验结果公布后,颈动脉内膜切除术在颈动脉粥样硬化性疾病治疗中的地位已毋庸置疑。该项外科手术技术虽然在中国起步较晚,但其发展前景良好。     

Measurement of Carotid Stenosis: Comparisons Between Duplex and Different Angiographic Grading Methods

BACKGROUND AND PURPOSE: Endarterectomy has been proved to be an effective stroke prevention procedure. However, there are still inconsistencies between the results of different preoperative evaluation methods, which may sometimes complicate treatment plans. This study measured the discrepancies between different angiographic grading methods and attempted to further assess the accuracy of the carotid duplex examination according to these different angiographic grading methods. METHODS: One hundred seventy-one preendarterectomy carotid duplex examinations and angiograms were reviewed. All angiograms were measured blindly by one of the authors using the North American Symptomatic Carotid Endarterectomy Trial (N), the European Carotid Surgery Trial (E), and the common carotid (C) methods. The measurement results were further converted into the area of stenosis indices (N2, E2, and C2, respectively). By using regression testing, all results could be compared. The duplex examination data were then compared with the results of different angiographic measurement methods to evaluate their accuracy. RESULTS: The measurement results of all angiographic grading methods were well correlated. Using different angiographic grading systems as the gold standard, duplex examination for screening endarterectomy candidates produced the following results: According to the N method, accuracy was 74%; according to the E method, accuracy was 90%; and according to the C method, the accuracy rate was 92%. According to N2, accuracy was 88%; according to E2, accuracy was 94%; and according to C2, the accuracy rate was 93%. CONCLUSIONS: The measurement results of all 3 commonly used angiographic grading methods were linearly correlated with one another. (It is important to note that none of those standards should be treated as the only gold standard.) In this study, the duplex criteria have a greater accuracy rate according to E or C rather than N. However, this study also demonstrated that the cut point of the Doppler criteria is the determinant factor for accuracy rather than which gold standard was compared. Through careful adjustment of the cutoff criteria, carotid duplex can be highly accurate, despite the use of different reference standards.     

Concordance rates of Doppler ultrasound and CT angiography in the grading of carotid artery stenosis: a systematic literature review

Physicians have been increasingly relying on noninvasive imaging methods to grade carotid stenosis. The accuracy of Doppler ultrasound (DUS) and CT angiography (CTA) versus intra-arterial angiography (IA) has been assessed in many studies and at least two meta-analyses. Here, we performed a systematic review of studies that compared DUS to CTA. In a PubMed review of the literature from 2000 to 2009, we found 12 studies that compared DUS and CTA-based grading of carotid stenosis. Only 4 of them included at least 20 patients and provided data to classify the diseased arteries into the following categories: mild, moderate or severe NASCET stenosis or occlusion. We extracted 431 arteries from 244 patients (range per study: 48-164). It was not possible to distinguish symptomatic from asymptomatic stenoses. Nearly half arteries had severe stenosis (46% based on DUS and 43% based on CTA). The weighted kappa was 0.85 (95% CI 0.76-0.94), and the accuracy was 0.78. When the arteries were classified into medical and potentially surgical groups, the kappa was 0.76 (95% CI 0.70-0.83), and the accuracy was 0.89. Overall, 17% of the stenoses classified as medical based on DUS were reclassified as surgical based on CTA and 14% of the stenoses classified as medical based on CTA were reclassified as surgical based on DUS. The sparse available data comparing DUS and CTA suggest that the grading of a carotid stenosis as medical or potentially surgical remains uncertain in a relatively high proportion of patients.     

Prospective study on the complication rate of carotid surgery

BACKGROUND: Randomized trials of carotid endarterectomy for high-grade stenosis have shown a benefit for surgery under the condition of low perioperative complication rates. Concerns have been expressed that the complication rates of carotid surgery are higher in everyday practice and may vary considerably between centers. We prospectively established the complication rate for carotid surgery in a single institution. DESIGN: Prospective 2-year study. All patients received pre- and postoperative neurological evaluation. Laboratory tests included pre- and postoperative brain imaging, intracranial and neck vessel sonography, conventional angiography, magnetic resonance angiography, and intraoperative monitoring. PARTICIPANTS: 108 consecutive patients: 54 symptomatic patients fulfilling the inclusion criteria of the European Carotid Surgery Trial (ECST) and 54 asymptomatic patients fulfilling the inclusion criteria of the North American Trial on Asymptomatic Stenoses (ACAS). SETTING: Single academic center with a high volume of carotid endarterectomies (>50 per year). Participating center in ECST. MAIN OUTCOME MEASURES: Stroke or death as defined in the randomized trials. RESULTS: The overall complication rate was 8.3% (95% CI 4.1-15.6%). Complications were more frequent in patients with symptomatic stenosis (11.1%, CI 4.6-23.3%) than in asymptomatic cases (5.6%, CI 1.5-16.4%). Three patients died (2 strokes, 1 myocardial infarction). Disabling strokes were found in 2 patients (Rankin scale scores 3 and 4). Nondisabling strokes (Rankin scale score 1 and 2) occurred in 4 patients. The complication rates for symptomatic and asymptomatic patients were higher than the ones reported in the randomized trials, but 95% confidence intervals showed that the differences were not statistically significant. The point estimates of complication rates still supported a benefit of surgery for patients with symptomatic stenosis, but denied a positive effect of endarterectomy for patients with asymptomatic stenosis. CONCLUSION: In this center, a beneficial effect of carotid surgery for asymptomatic stenoses cannot be safely assumed.     

颈动脉支架成形术与药物治疗颈动脉狭窄的对比研究

目的 分析颈动脉支架成形术（CAS）与药物治疗颈动脉狭窄的疗效，并评价其安全性。方法 2003年11月至2006年3月采用颈动脉支架成形术治疗颈内动脉狭窄（狭窄率≥50％）21例,于围手术期进行抗血小板治疗及控制危险因素。单纯药物治疗组53例，药物治疗方案同治疗组。临床随访6～28个月。结果 21例手术操作完全成功，术后残余狭窄＜30％，术中3例患者出现一过性心率减慢、血压下降，2例出现颈内动脉远端血管痉挛，治疗后好转；术后未发生新的卒中，颈动脉超声未显示再狭窄。药物治疗组随访期间，5例患者再发卒中，颈动脉超声检查发现14例患者狭窄程度加重，其中2例血管造影证实颈内动脉完全闭塞。结论 与药物治疗组比较，CAS治疗颈内动脉狭窄可以提高患者的生活质量，而且比较安全，短期疗效较好，但有待大样本研究结果证实     

Comparison of ultrasound and IV-DSA for carotid evaluation

Sixty carotid bifurcations in 34 symptomatic patients were examined prospectively with ultrasound (continuous wave Doppler and high resolution, B-mode imaging) and intravenous digital subtraction angiography (IV-DSA). The overall quality of examination was better with DSA than with ultrasound. Imaging of the external carotid artery was particularly difficult with sonography. For evaluation of the common and internal carotid arteries, eight percent of IV-DSA studies were poor or inadequate as compared with 12% for B-mode imaging. Overall for detection of atherosclerotic plaque, high resolution B-mode sonography was 84% sensitive and DSA 81% sensitive. When only the common and internal carotid arteries were considered, the sensitivity of high resolution sonography improved to 93% and the sensitivity of IV-DSA increased to 86%. Ultrasound (combined high resolution, B-mode sonography and CW Doppler) correctly identified all six internal carotid occlusions in the series. While IV-DSA correctly identified five of the six occlusions, the sensitivity for detection of lesions causing 70% or more stenosis was 95% for both ultrasound and IV-DSA. Sensitivity for 50% or greater obstruction was 79% for ultrasound and 85% for IV-DSA. Ultrasound sensitivity for greater than 50.9% stenoses rose to 87% when only the common and internal carotid were considered while IV-DSA sensitivity remained at 85%. Specificity was good at all levels of obstruction. It may be concluded from this study that the accuracy of ultrasound and IV-DSA are quite similar for evaluation of the carotid bifurcation and that either test is a satisfactory screening method for carotid bifurcation atheromatous disease.     

Time trends in the published risks of stroke and death due to endarterectomy for symptomatic carotid stenosis

BACKGROUND: Large randomised trials performed in the 1980s and early 1990s showed that carotid endarterectomy (CEA) is beneficial for patients with recently symptomatic severe stenosis. Some surgeons have argued that the operative risk of stroke and death has fallen over the last decade due to refinements in operative technique, and that the indications for surgery should therefore now be broadened. Yet, studies of routinely collected data report higher operative mortality than in the trials, and surgical case series without independent post-operative assessment by a neurologist may not provide reliable data on stroke risk. METHODS: We performed a systematic review of all studies published between 1994 and 2001 inclusive that which reported the risks of stroke and death for symptomatic carotid stenosis, and compared the reported risks and patient characteristics with those in the ECST and NASCET and with our previous review of studies published prior to 1995. Pooled estimates of the operative risk of stroke and death were obtained by Mantel-Haenszel meta-analysis. RESULTS: Of 383 studies published between 1994 and 2001, only 45 reported operative risks for patients with symptomatic stenosis separately. The pooled operative risk of stroke and death reported in studies published by surgeons only (4.2%, 95% CI = 2.9-5.5, 34 studies) was significantly lower (p < 0.0001) than that in the ECST and NASCET combined (7.0%, 95% CI = 6.2-8.0), whereas the pooled risk reported in studies that involved neurologists was similar (6.5%, 95% CI = 4.3-8.7, 11 studies, p = 0.6). In contrast, operative mortality in ECST and NASCET was significantly lower than in other studies published between 1994 and 2001. By comparison with our previous review, when stratified according to involvement of neurologists, we found no evidence of a reduction in published risks of death or stroke and death due to CEA between 1985 and 2001. CONCLUSIONS: There is no evidence of a systematic reduction over the last decade in the published risks of stroke and death due to CEA for symptomatic stenosis. Operative risks in studies with comparable outcome assessment are similar to ECST and NASCET. The surgical data from the large trials are still likely therefore to be applicable to routine clinical practice.     

Overestimation of moderate carotid stenosis assessed by both Doppler US and contrast enhanced 3D-MR angiography in the CARMEDAS study

Purpose

To evaluate the agreement and diagnostic accuracy of Contrast enhanced magnetic resonance angiography (CE-MRA), Doppler ultrasound (DUS) and Digital subtraction angiography (DSA) in the assessment of carotid stenosis.

Methods

DUS, CE-MRA and DSA were performed in 56 patients included in the Carotide-angiographie par résonance magnétique-échographie-doppler-angioscanner (CARMEDAS) multicenter study with a carotid stenosis ≥ 50%. Three readers evaluated stenoses on CE-MRA and DSA (NASCET criteria). Velocities criteria were used for stenosis estimation on DUS.

Results

CE-MRA had a sensitivity and specificity of 96–98% and 66–83% respectively for carotid stenoses ≥ 50% and a sensitivity and specificity of 94% and 76–84% respectively for carotid stenoses ≥ 70%. The interobserver agreement of CE-MRA was excellent, except for moderate stenoses (50–69%). DUS had a sensitivity and specificity of 88 and 75% respectively for carotid stenoses ≥ 50% and a sensitivity and specificity of 83 and 86% respectively for carotid stenoses ≥ 70%. Combined concordant CE-MRA and DUS had a sensitivity and specificity of 100 and 85–90% respectively for carotid stenoses ≥ 50% and a sensitivity and specificity of 96–100% and 80–87% respectively for carotid stenoses ≥ 70%. The positive predictive value of the association CE-MRA and DUS for carotid stenoses ≥ 70% is calculated between 77 and 82% while the negative predictive value is calculated between 97 and 100%. CE-MRA and DUS have concordant findings in 63–72%, and the overestimations cases were recorded only for carotid stenosis ≤ 69%.

Conclusion

Combined DUS–CE-MRA is excellent for evaluation of severe stenosis but remains debatable in moderate stenosis (50–69%) due to the risk of overestimations.     

Association between arterial bifurcation anatomy and angiographic plaque ulceration among 4,627 carotid stenoses

Stability of atheromatous plaques is influenced by local mechanical and haemodynamic factors, such as plaque motion and shear stress. However, although blood vessel anatomy is an important determinant of haemodynamics, particularly at bifurcations, there have been no previous clinical studies of the association between arterial anatomy and plaque ulceration. We therefore studied arterial anatomy and plaque ulceration using angiograms of 4,627 carotid bifurcations with atheromatous disease from the European Carotid Surgery Trial (ECST). We studied the vessel diameter and area ratios that have been shown in flow models to affect local haemodynamics and shear stress, and which are known to vary widely between and within individuals (internal to common, external to common, external to internal carotid artery and outflow/inflow area). Angiographic plaque surface morphology was defined as ulcerated or not ulcerated. To avoid any potential bias due to selective inclusion of patients in the ECST, we studied the contralateral, and usually asymptomatic, as well as the symptomatic carotid artery. To correct for the effects of systemic factors that might influence plaque stability, we also studied the relationship between the degree of asymmetry of bifurcation anatomy within individuals and the presence of plaque ulceration. Despite considerable inter-individual variation in carotid anatomy, we found no association between the prevalence of angiographic plaque ulceration and any of the anatomical parameters studied in either symptomatic or contralateral carotid arteries. There were also no associations between ipsilateral bifurcation anatomy and plaque ulceration in individuals with unilateral plaque ulceration. Carotid arterial anatomy does not appear to be an important determinant of plaque stability. Other factors that influence local haemodynamics, such as the anatomy and composition of the plaque itself may be more important.     

Continuous wave Doppler ultrasonography in the detection of carotid stenosis and occlusion.

Directional continuous wave Doppler ultrasonography has been used to assess the extracranial carotid arteries of over 500 patients, 90 of whom have had angiography performed. The angiographic and Doppler findings are compared, showing that this simple ultrasound technique is able to detect carotid stenosis and occlusion, but is unreliable in the detection of mild atheromatous change. In this series, the method detected 90% of the angiographically proven carotid stenoses, being considerably more accurate than routine auscultation. It would seem that continuous wave ultrasonography is a safe and practical screening test in those patients in whom arteriography is being considered.     

Analysis of agreement between measurements of continuous variables: general principles and lessons from studies of imaging of carotid stenosis

Clinical research often involves measurement of continuous variables. However, clinical measurements are seldom precise. It is frequently necessary, therefore, either for the reproducibility of measurement to be assessed (observer agreement studies), or for measurements made by different techniques to be compared (method comparison studies). There are numerous ways in which data can be analysed and reported in such studies, and several pitfalls. In order to determine which methods are commonly used in the medical literature, a systematic review of studies involving measurement of carotid stenosis was performed. A random sample of 40 studies were selected for detailed assessment. The methods of analysis of reproducibility of measurement of stenosis and/or comparison of two alternative techniques of measurement were recorded. Ten different methods were identified. The advantages and disadvantages of each of the methods are discusses in a non-technical and non-mathematical manner, and illustrated using data from a study of measurement of carotid stenosis by two observers on 1001 carotid angiograms. Received: 25 April 2000 / Accepted: 2 May 2000     

颈动脉内膜斑块剥脱术治疗颈内动脉狭窄(附16例报告)

目的探讨颈动脉内膜斑块剥脱术的手术适应证、操作要点和麻醉方法。方法回顾性分析2004年11月至2009年12月经颈动脉内膜斑块剥脱术治疗的16例颈内动脉狭窄患者的临床资料。16例患者均有临床症状,其中颈内动脉中度狭窄者2例,重度狭窄者14例。均采用经气管内插管全身麻醉,术中应用诱导性高血压,应用显微外科技术剥除颈动脉内膜斑块,所有病例均未应用术中转流术。结果术后均行多普勒超声检查,结果示颈动脉血流量较术前明显增加。12例反复发作一过性脑缺血的患者术后随访6个月均未再发作。1例糖尿病合并高血压有脑卒中史者死亡,其余患者随访6个月至2年脑缺血症状明显改善。结论颈内动脉内膜斑块剥脱术是颈动脉狭窄安全有效的治疗方法。     

Small Carotid Thrombus and Minimal Stenosis Causing Repeated Embolic Strokes

Despite current developments in neuroradiology, the sources of infarctions go undiagnosed in 28% of cases. An embolic source in the setting of minimal stenosis at the carotid bifurcation has rarely been reported. The authors report a previously healthy 48‐year‐old woman, without any risk factors for cerebrovascular events, sustained multiple cerebral infarctions in the right anterior and middle cerebral artery territory. Repeated imaging of the heart and cerebral vessels missed a very small abnormality arising from the posterior wall of the internal carotid artery, until it was diagnosed by computed tomographic angiography. This is problematic because by North American Symptomatic Carotid Endarterectomy Trial (NASCET) criteria, minimal stenosis essentially excludes the carotid artery as an embolic source. Despite maximum antiplatelet and anticoagulation therapy, she continued to have neurological deteriortation by progression of her strokes. She underwent standard carotid endarterectomy and sustained no new embolic phenomena. Histopathological examination showed an endothelial hyperplasia with organizing thrombus, which on the posterior wall of the internal carotid artery, is likely a hemodynamically induced on top of preexisting atherosclerotic plaque.     

Stroke prevention by surgery for symptomatic disease in carotid territory.

The benefit of surgical procedures in preventing stroke is of concern to physicians, surgeons, and all health-care providers. The multicenter randomized trial has been applied in evaluating these strategies. Extracranial-intracranial anastomosis has failed to measure up to this rigid form of scientific scrutiny and the reasons for the demise of this procedure are reviewed. By contrast, for symptomatic disease of the internal carotid artery, patients with very severe stenosis are better treated by endarterectomy than with medical care alone. The ongoing North American Symptomatic Carotid Endarterectomy Trial (NASCET) is reviewed and the compelling reasons to continue the trial for patients with moderate disease are outlined.     

Cerebrovascular reserve capacity

Cerebrovascular reserve capacity (CVR) describes how far cerebral perfusion can increase from a baseline value after stimulation. Measurement of cerebral blood flow (CBF) can be done by PET or SPECT. Noninvasive and easily performed transcranial Doppler sonography (TCD) is mostly used as indirect perfusion measurement. Stimulation of cerebral perfusion is often done by CO2 inhalation or acetazolamide injection. Alternative stimuli are breath holding or cerebral activation by hand-gripping. Normal values for these tests are presented. The hemodynamic effect of stenoses of the internal carotid artery (ICA) can be estimated using CVR. The relevance of CVR is discussed controversially, since cerebral infarction due to stenosis of arteries supplying the brain is probably mostly of embolic, not hemodynamic origin. The indication for carotid artery surgery according the NASCET and ECST investigations takes into account only the degree of the stenoses and not the CVR. According to recent studies, the risk of cerebral infarction in these patients is considerably higher with reduced CVR. Therefore, CVR can be used as an additional parameter if the indication for surgery is not defined, especially in asymptomatic carotid artery stenosis. It seems also possible to identify patients who might profit from an extra-intracranial bypass operation and high-risk patients for cerebral ischemia with cerebral microangiopathy. Furthermore, the risk of cerebral infarction during carotid artery surgery and also during heart surgery can be estimated using CVR. More studies with a higher number of patients are needed to confirm the potential predictive diagnostic value of CVR in order to establish CVR measurement as part of a routine diagnostic neuroangiologic program.     

脑血流有效灌注压的无创检测及其对急性脑梗死的临床意义

目的 探索脑血流有效灌注压（effective cerebral perfusion pressure,CPPe）的无创检测方法的有效性
以及急性脑梗死患者CPPe与颈内动脉血管狭窄程度的相关性。
方法 本研究为前瞻性研究,收集2010年1月～2012年1月在广州医科大学附属第二医院神经内科住院
的41例发病1周内的急性脑梗死患者,所有患者均经数字减影血管造影（digital subtraction angiography,
DSA）和经颅多普勒超声（transcranial Doppler ultrasonography,TCD）评估颈内动脉狭窄程度及大脑中动
脉无创血压、有创血压及血流速度,根据上述检测结果计算CPPe,比较TCD、DSA评价CPPe的有效性。
同时根据北美症状性颈动脉狭窄内膜切除研究（North American Symptomatic Carotid Endarterectomy
Trial,NASCET）标准分为轻度狭窄组、中度狭窄组和重度狭窄组,比较各组间的血管狭窄危险因素、
CPPe和美国国立卫生研究院卒中量表（National Institutes of Health Stroke Scale,NIHSS）评分,以及CPPe
和NIHSS评分与颈内动脉血管狭窄程度的相关性。
结果 所有急性脑梗死患者的有创和无创CPPe比较,结果发现有创CPPe的中位数为56.6 mmHg,无
创CPPe的中位数为57.8 mmHg,两者之间的差异无显著性（P＞0.05）。轻度狭窄组、中度狭窄组和重度
狭窄组3组急性脑梗死患者的有创CPPe的中位数分别为60.6 mmHg、42.5 mmHg和1.6 mmHg;无创CPPe
的中位数分别为62.2 mmHg、42.7 mmHg和0.27 mmHg;NIHSS评分的中位数分别为4、3和8;比较CPPe、
NIHSS评分在各组间的差异有显著性,H值分别为26.906、26.906及11.233（P＜0.01）。相关分析显示急
性脑梗死患者CPPe与DSA显示的血管狭窄程度密切相关,相关系数分别为－0.782和－0.814,差异有显
著性（P＜0.01）;而NIHSS评分与DSA显示的血管狭窄程度无相关性,相关系数为0.222,差异无显著性
（P＞0.05）。
结论 通过TCD无创检测并计算CPPe的新方法可以获得较为准确的CPPe,而且CPPe与急性脑梗死患
者的颈内动脉狭窄程度密切相关,这使得CPPe可能可以为脑血管病患者无创脑血流检测、指导个体
化血压调控提供可靠证据。