Effect Of Carotid Endarterectomy Research Articles

Reproducibility of Measures of Visit-to-Visit Variability in Blood Pressure after Transient Ischaemic Attack or Minor Stroke

Background: In certain patients in routine practice, blood pressure (BP) measurements differ substantially from week to week or month to month. Although often assumed to be random, such variability could provide information on underlying pathology or prognosis. In order to be informative, however, visit-to-visit BP variability would have to be neither random (i.e. it should be reproducible over time within individuals) nor artefactual (i.e. it should not be an artefact of the method/timing of measurement, for example). Methods: We quantified visit-to-visit variability in BP and explored potential confounding factors by analysing repeat measurements obtained every few months during follow-up in two large trials in patients with a transient ischaemic attack (TIA) or minor ischaemic stroke: the UK-TIA Aspirin Trial (effect of aspirin, effect of season and day of the week of measurement) and the European Carotid Surgery Trial (ECST – effect of carotid endarterectomy). By comparing different periods of follow-up, we also determined the reproducibilities of mean and several different measures of variability for both systolic (SBP) and diastolic BP (DBP). Results: The mean absolute difference between adjacent SBP readings was 14.7 mm Hg in the UK-TIA Trial and 16.0 mm Hg in ECST. Visit-to-visit variability in both SBP and DBP were independent of the potentially confounding factors studied, but reproducibility of all the variability measures was statistically significantly greater than zero. Reproducibility (intraclass correlation) of standard deviation of SBP was 0.32 (p < 0.0001) in the UK-TIA Trial and 0.18 (p = 0.0007) in ECST. Consequently, classification of patients with high (top quintile) or low (bottom quintile) variability was consistent over time (observed/expected = 2.21, 95% confidence interval 1.71–2.85, p < 0.0001, and 1.65, 1.23–2.21, p = 0.0007, respectively). Reproducibility increased with the number of measurements used to calculate variability, and was independent of any correlation with mean BP. Conclusions: Visit-to-visit variability in BP in these populations was reproducible, independently of any correlation with mean BP, demonstrating that visit-to-visit intra-individual BP variability is not random.

Efficacy of the Carotid Endarterectomy in Asymptomatic and Symptomatic Carotid Stenosis and in Patients with Multifocal Atherosclerosis

Aim. The aim of the research was to study the effect of carotid endarterectomy (CEA) at patients with asymptomatic and symptomatic carotid stenosis, also in the patients with multifocal atherosclerosis (MFA): carotid stenosis in patients with peripheral arterial disease (PAD) of the limbs and ischemic heart disease (IHD). Material and methods. Colour Duplex Doppler was used for screening of carotid pathology in 1104 patients with PAD, IHD, transitory ischemic attacks and an ischemic stroke. The group of 205 patients who had stenosis of a. carotis interna >60%, were divided into three subgroups – patients with asymptomatic carotid stenosis (ACS), patients with symptomatic carotid stenosis (SCS) and patients with multifocal atherosclerosis MFA. Results. All 205 patients were subjected to CEA, conducted by a patch or shunt, which was successful performed at 201 patients (98%). Significant improvement of hemodynamic of the regional carotid as well as intracranial arteries on the side of the surgery was determined using Colour Duplex and Transcranial Doppler Sonography (TDS). At a second stage, after the successful CEA, a vascular reconstruction was carried out or an aorto-coronary bypass created in the case of patients with MFA. Conclusion. CEA in the case of patients with asymptomatic and symptomatic carotid stenosis and a concurrent MFA is an efficient curative method of removing the carotid pathology with a minimum percentage of vascular complications. OPEN ACCESS

What happens to the external carotid artery following carotid endarterectomy?

AimsThe effect of carotid endarterectomy on the patency of the external carotid artery is unknown. We conducted a retrospective study to evaluate the long-term changes in the external carotid artery following carotid endarterectomy.MethodsData was prospectively recorded for all patients who had carotid endarterectomy between 1997 and 2006 in our vascular surgical unit. These patients had follow-up with carotid duplex ultrasound to assess the patency of the internal and external carotid artery. The data were retrieved and evaluated for patency and flow characteristic in both arteries before and after surgery.ResultsCarotid endarterectomy was performed on 255 occasions in 236 patients over the ten year study period. Immediate and long-term outcome of carotid endarterectomy is comparable to results at other major centers. Stenosis of the external carotid artery as detected by duplex scan occurred in 5.5% of patients and was totally asymptomatic.ConclusionOur results of carotid endarterectomy are comparable to other centers. Long-term follow up of the external carotid artery with duplex scan showed asymptomatic stenosis in a small percentage of patients.

Cognitive Functions in Carotid Artery Disease before Endarterectomy

Restorative effects of carotid endarterectomy (CEA) on cognitive functioning in patients with severe atherosclerotic disease presuppose the existence of cognitive deficits prior to the intervention. Thorough examination of this premise received only minor attention. The present study assessed symptomatic and asymptomatic patients with severe unilateral or bilateral stenosis of the carotid arteries one day before CEA. Healthy volunteers with similar demographic characteristics served as control subjects. Patients overall showed decreased functioning on tests of attention, verbal and visual memory, verbal fluency, and psychomotor speed and executive functioning, even after correction for the effects of mood. Simple motor skills and visuospatial functioning were not affected. Patients grouped according to presence and type of previous clinical symptoms and severity of contralateral stenosis only slightly differed from each other. The findings leave open the potential of improving cognitive function after CEA. We thank the staff of the Department of Vascular Surgery from the St. Antonius Hospital for help in the arrangement of meetings with patients, and Nicole Dreessen, Christi-Anne van Hattum, Cindy de Graag, Lindsey Ossewaarde, Greet Huisman, Roeland van der Zouwen, and Ingrid Verkerk for their help in data collection.

Effect of carotid endarterectomy on cerebral blood flow and its response to hypercapnia.

Cerebral blood flow (CBF) was measured in 14 patients before carotid endarterectomy, 3 h after surgery and 2 days postoperatively using the intravenous xenon-133 technique. In 11 of the patients CBF was remeasured at 6 months and in 8 patients CBF and the response to hypercapnia (5 per cent CO2 in air) was measured pre-operatively and 6 months following surgery. All operations were performed using an intraluminal Javid shunt and internal carotid artery (ICA) 'stump' pressure was recorded. CBF measured at 3 h after endarterectomy revealed a postoperative cerebral hyperperfusion with significantly increased flows in both hemispheres. There was a significant correlation between carotid cross clamping time and ipsilateral hemispheric CBF increase which implied an ischaemic aetiology for the hyperperfusion and supported the routine use of an intraluminal shunt in carotid endarterectomy. Six months after surgery, CBF had returned to its preoperative value but reactivity to CO2 was significantly improved, which suggested that the operation had increased cerebral reserve.

Serial imaging of the carotid bifurcation and cerebrovascular reserve after carotid endarterectomy.

A radioisotopic method of quantifying mean cerebral transit time was used to assess the immediate effects of carotid endarterectomy on cerebrovascular reserve (CVR) in 69 patients. In addition, serial postoperative data were acquired on CVR, clinical status and non-invasive imaging of the internal carotid arteries in 56 patients over a period of 6-48 (median 24) months. Twenty-one patients (30 per cent) had preoperative evidence of impaired CVR in the symptomatic hemisphere. Within 4 days of surgery, however, reserve had returned to normal in 17 of the 21 patients. During follow-up, four of the 56 patients developed recurrent stenosis (> 50 per cent) or occlusion of the artery operated on but only two of these had impairment of CVR and none was symptomatic. Three patients suffered recurrent transient ischaemic attacks (TIAs) but none had recurrent internal carotid artery disease or impaired CVR. One patient suffered a TIA in the territory of the non-operated artery during follow-up in association with disease progression and CVR impairment. However, the TIA preceded recognition of either of these changes. Twelve other patients had (or developed) stenosis (> 50 per cent) in the non-operated artery during follow-up but none was symptomatic or developed impairment of CVR. Although assessment of CVR provided useful information on the frequency of haemodynamic compromise before carotid endarterectomy and on the natural history of disease progression, neither serial assessment of reserve nor non-invasive imaging of the carotid bifurcation influenced clinical practice during follow-up.

The effects of carotid endarterectomy on the mechanical properties of the carotid sinus and carotid sinus nerve activity in atherosclerotic patients.

Abstract The hypothesis that instability of blood pressure occurring after carotid endarterectomy is related to interference with mechanical properties of the arterial wall in the region of the carotid sinus was investigated in 11 patients undergoing carotid surgery for transient ischaemic neurological disturbances. The operative procedure was found to change the mechanical properties of the arterial wall, there being an overall increase in diameter and reduction in distensibility, and these changes were reflected in the recorded change of spontaneous sinus nerve activity and the systemic blood pressure. It is suggested that the sinus nerve and carotid baroreceptor region should be carefully preserved during carotid endarterectomy to prevent reflex postoperative hypertension. Should hypotension occur in the postoperative phase it can be treated by local anaesthesia of the sinus region, anaesthetic blockade being maintained until secondary adaptation of the receptors takes place.

Extracranial carotid artery flow measurement during carotid endarterectomy using a Doppler ultrasonographic flowmeter.

A study was performed to evaluate immediate changes in carotid artery blood flow after carotid endarterectomy using a Doppler ultrasonographic flowmeter. Forty-seven consecutive patients aged 49-78 (median 64) years with symptomatic internal carotid artery (ICA) stenosis underwent carotid endarterectomy. Volume flow, resistance and pulsatility index were measured in the common carotid artery (CCA) and ICA both before and after operation. ICA flow increased by 54 per cent (P < 0.01) and resistance decreased by 58 per cent (P = 0.01). CCA flow rose by 17 per cent (P = 0.1) and resistance fell by 21 per cent (P = 0.02). The pulsatility index did not change significantly. The Doppler ultrasonographic flowmeter offers a simple, non-invasive and convenient means of improving understanding of the immediate haemodynamic effects of carotid endarterectomy. It is useful in everyday practice to confirm the adequacy of endarterectomy, particularly in the absence of other methods of quality control. Duplex ultrasonography might still be necessary after surgery if the flowmeter does not demonstrate an increase in flow compared with the preoperative value.

Effect of awake Carotid Endarterectomy under local anaesthesia on peri-operative blood pressure: blood pressure is normalised when carotid stenosis is treated under local anaesthesia

Carotid Endarterectomy can be performed under local, regional or general anaesthesia. One of the most important effects of the type of anaesthetic used is on the systemic blood pressure. Although variations in blood pressure during and following carotid endarterectomy have been studied previously, the effects of awake carotid endarterectomy under local anaesthesia on blood pressure and its comparison with similar procedures under similar types of anaesthesia have not. Peri-operative blood pressure measurements were collected from the records of 25 consecutive patients for each of the following five procedures; Carotid Endarterectomy under general anaesthesia (CEAGA), Anterior Cervical Discectomy and Fusion under general anaesthesia (ACDF), Cerebral Angiography under local anaesthesia (ANG), Carotid Endarterectomy patients under local anaesthesia who were symptomatic (CEALAS) and Carotid Endarterectomy patients under local anaesthesia who were asymptomatic (CEALAA). The recordings were then analysed to find out if there were any clinically significant variations in peri-operative blood pressure. There is a significant and consistent difference when the pre-operative value was compared with the 4 hour and 24 hour post-operative recordings between the local and general anaesthetic groups for carotid endarterectomy. Carotid endarterectomy reduces the systolic and diastolic blood pressures post-operatively when performed under local anaesthesia and only the diastolic pressure was reduced when performed under general anaesthesia. The study provides evidence about the effect of carotid endarterectomy on the systemic blood pressure and its variations when performed under different types of anaesthesia. There is significant post-operative reduction in both the systolic and diastolic blood pressure values and the intraoperative fluctuation is minimal when local anaesthesia is used. Further studies are required to find out how this affects the long-term blood pressure and clinical outcome of the patient.

Effects of carotid endarterectomy on motor evoked potentials elicited by transcranial magnetic stimulation

To investigate the within 3 days effects of carotid endarterectomy (CEA) on functional status of the central motor system in patients with carotid stenosis by means of transcranial magnetic stimulation (TMS). We studied 30 consecutive patients, 20 males and 10 females with a mean age of 69.2+/-7.1 years, who underwent CEA for symptomatic carotid stenosis. All patients had suffered an ischemic attack 6 months prior to the operation. Two TMS studies, one before and one shortly after CEA were performed on both sides in each of the patients. Resting motor threshold, motor evoked potentials (MEP) amplitude at rest, MEP latency at rest and during contraction and silent period duration (SPD) were recorded and analyzed. Two groups of data were collected. Group 1 consisted of data from the operated side in all 30 patients. Group 2 consisted of data from the contralateral side and served as a control. Motor resting thresholds were similar in the two groups. Intragroup pre and post CEA comparisons showed no difference in the operated group and significant increased threshold after CEA on the non-operated side. There was no significant difference of TMS intensity for maximal MEP in either side before or after CEA. Latency at rest and during voluntary contraction and amplitude at rest showed no significant differences between or within groups' comparisons. In group 1 SPD showed a statistically significant increase after CEA as opposed to baseline. In group 2 SPD showed a non significant increase after CEA. In the absence of other MEP changes, our finding of prolonged SPD post-operatively suggests preferential influence of the inhibitory cortical circuits. The potential favorable effect of CEA in patients with hyperexcitability such as disabling spasticity after stroke should be further studied.

Invited Commentary

Bossema et al have presented a study of cognitive function in patients undergoing carotid endarterectomy. The neuropsychologic tests may not be familiar to vascular surgeons, although this topic has been addressed in several recent articles.1Antonelli Incalzi R. Gemma A. Landi F. Pagano F. Capparella O. Snider F. et al.Neuropsychologic effects of carotid endarterectomy.J Clin Exp Neuropsychol. 1997; 19: 785-794Crossref PubMed Scopus (27) Google Scholar, 2Ucles P. Almarcegui C. Lorente S. Romero F. Marco M. Evaluation of cerebral function after carotid endarterectomy.J Clin Neurophysiol. 1997; 14: 242-249Crossref PubMed Scopus (14) Google Scholar, 3Irvine C.D. Gardner F.V. Davies A.H. Lamont P.M. Cognitive testing in patients undergoing carotid endarterectomy.Eur J Vasc Endovasc Surg. 1998; 15: 195-204Abstract Full Text PDF PubMed Scopus (53) Google Scholar, 4Aharon-Peretz J. Tomer R. Gabrieli I. Aharonov D. Nitecki S. Hoffman A. Cognitive performance following endarterectomy in asymptomatic severe carotid stenosis.Eur J Neurol. 2003; 10: 525-528Crossref PubMed Scopus (27) Google Scholar, 5Fearn S.J. Hutchinson S. Riding G. Hill-Wilson G. Wesnes K. McCollum C.N. Carotid endarterectomy improves cognitive function in patients with exhausted cerebrovascular reserve.Eur J Vasc Endovasc Surg. 2003; 26: 529-536Abstract Full Text Full Text PDF PubMed Scopus (63) Google Scholar, 6Kishikawa K. Kamouchi M. Okada Y. Inoue T. Ibayashi S. Iida M. Effects of carotid endarterectomy on cerebral blood flow and neuropsychological test performance in patients with high-grade carotid stenosis.J Neurol Sci. 2003; 213: 19-24Abstract Full Text Full Text PDF PubMed Scopus (51) Google Scholar, 7Pearson S. Maddern G. Fitridge R. Cognitive performance in patients after carotid endarterectomy.J Vasc Surg. 2003; 38: 1248-1253Abstract Full Text Full Text PDF PubMed Scopus (31) Google Scholar Comparison with a group without known vascular disease and a group undergoing surgery for lower extremity arteriosclerosis is novel. Experimental groups were comparable for other than the usual predictors of atherosclerosis. Control subjects did not undergo repeat testing, which would have allowed better assessment of the training effect addressed in the surgical groups. However, the study provides some fascinating insights into possible cognitive dysfunction in subjects with both carotid and lower-extremity atherosclerosis. Subjects with overt stroke were excluded, implying no evidence of cerebral dysfunction on conventional neurologic examination. Nevertheless, when compared using neuropsychologic tests, subjects with carotid or lower-extremity atherosclerosis scored less well than healthy controls, suggesting the presence of some systemic vascular disease. This also speaks to the crudeness of the standard neurologic examination as a test for higher cerebral functions. The investigators showed no cognitive improvement with carotid endarterectomy. Pearson et al7Pearson S. Maddern G. Fitridge R. Cognitive performance in patients after carotid endarterectomy.J Vasc Surg. 2003; 38: 1248-1253Abstract Full Text Full Text PDF PubMed Scopus (31) Google Scholar made similar observations in this journal. This may at first seem disappointing, but is consistent with the concept that carotid endarterectomy is prophylactic. This conflicts with the results of some previous studies,1Antonelli Incalzi R. Gemma A. Landi F. Pagano F. Capparella O. Snider F. et al.Neuropsychologic effects of carotid endarterectomy.J Clin Exp Neuropsychol. 1997; 19: 785-794Crossref PubMed Scopus (27) Google Scholar, 5Fearn S.J. Hutchinson S. Riding G. Hill-Wilson G. Wesnes K. McCollum C.N. Carotid endarterectomy improves cognitive function in patients with exhausted cerebrovascular reserve.Eur J Vasc Endovasc Surg. 2003; 26: 529-536Abstract Full Text Full Text PDF PubMed Scopus (63) Google Scholar, 6Kishikawa K. Kamouchi M. Okada Y. Inoue T. Ibayashi S. Iida M. Effects of carotid endarterectomy on cerebral blood flow and neuropsychological test performance in patients with high-grade carotid stenosis.J Neurol Sci. 2003; 213: 19-24Abstract Full Text Full Text PDF PubMed Scopus (51) Google Scholar but there may be methodologic problems with some of those studies.3Irvine C.D. Gardner F.V. Davies A.H. Lamont P.M. Cognitive testing in patients undergoing carotid endarterectomy.Eur J Vasc Endovasc Surg. 1998; 15: 195-204Abstract Full Text PDF PubMed Scopus (53) Google Scholar We wonder what might have been observed had cognitive testing been performed in trials such as NASCET, ECST, and ACAS.8North American Symptomatic Carotid Endarterectomy Trial CollaboratorsBeneficial effect of carotid endarterectomy in symptomatic patients with high-grade carotid stenosis.N Engl J Med. 1991; 325: 445-453Crossref PubMed Scopus (7402) Google Scholar, 9European Carotid Surgery Trialists’ Collaborative GroupMRC European Carotid Surgery Trial interim results for symptomatic patients with severe (70–99%) or with mild (0–29%) carotid stenosis.Lancet. 1991; 337: 1235-1243Abstract PubMed Scopus (2977) Google Scholar, 10Executive Committee for the Asymptomatic Carotid Atherosclerosis StudyEndarterectomy for asymptomatic carotid artery stenosis.JAMA. 1995; 273: 1421-1428Crossref PubMed Scopus (4853) Google Scholar Would the status of nonsurgical subjects have deteriorated as assessed by cognitive testing? Would the number of nonsurgical subjects whose status deteriorated have exceeded the number identified on conventional examination as having had a stroke? Future trials in carotid intervention, including carotid angioplasty, should build on the observations of Bossema et al and should consider designs that allow serial neuropsychologic testing in all treatment arms, including control groups without known vascular disease.

Is mild vascular cognitive impairment reversible? Evidence from a study on the effect of carotid endarterectomy

Mild vascular cognitive impairment (mVCI) is a broader term that is intended to detect cognitive loss before the development of dementia. The identification of preventable risk factors as well as therapeutic strategies of intervention is still unclear. It has been suggested that carotid endarterectomy (CEA) improves cognitive functions, beyond the well-known preventive effect upon future stroke events. In the present study, we evaluated the beneficial effect of CEA in restoring mVCI. Among a large sample of subjects, who underwent CEA for severe carotid stenosis, two groups were identified according to the absence (CON) or the presence of cognitive impairment (mVCI). A multidimensional neuropsychological and behavioural assessment was performed in the week prior, and at a 3-month follow-up after CEA. The incidence of mVCI in this sample was 38%. Seventy-eight patients completed the follow-up (48 CON, 30 mVCI). Both groups showed a clinical improvement after CEA, although the effect was significantly higher in the mVCI group in regard to verbal memory (short story, p < 0.05), and attention (digit span, p < 0.05) scores. At follow-up, 60% of mVCI subjects were classified as having normal cognitive functions. Index of disease severity and peripheral arterial disease were found to be the predictors of improvement. These findings support that mVCI represents a heterogeneous, in some cases reversible condition. CEA might be considered a therapeutic option to treat and prevent cognitive decline in mVCI patients.

Effects of carotid endarterectomy on cerebral blood flow and neuropsychological test performance in patients with high-grade carotid stenosis

We examined the changes in cognitive function following carotid endarterectomy (CEA) in relation to the cerebral blood flow (CBF) in patients with high-grade carotid stenosis. The subjects consisted of 23 patients who underwent CEA and 17 controls matched by age and education. Single photon emission computed tomography (SPECT) and neuropsychological tests were performed 2 weeks before and 4 weeks after CEA in all patients. The preoperative CBF tests revealed a decreased vasodilatory reserve in the ipsilateral cerebral hemisphere in nine patients, which was increased after CEA. In these patients, the grade of carotid stenosis was significantly higher than in those with a normal perfusion reserve (90.2±8.1% vs. 78.6±11.3%, respectively, p<0.05). In the patient group, the postoperative scores (27.2±2.9) of the mini-mental state examination (MMSE) improved significantly over the preoperative ones (26.1±3.2, p<0.05). Moreover, the scores in the block-design test after CEA (86.8±19.8) were significantly higher than those before the operation (81.8±22.3, p<0.01). The error score in immediate retention improved from 9.0±3.1 to 7.7±4.0 following CEA ( p<0.05). In the control group, none of the test scores showed significant improvement between the first and second tests. In the patients with an impaired vasodilatory reserve, the mean score of the block-design test significantly improved from 65.6±22.1 to 74.0±19.2 after CEA compared with those in patients without impairment ( p<0.05). High-grade carotid stenosis was thus concluded to cause cognitive impairment due to cerebral hemodynamic failure, which is presumably reversed by CEA.

Prognosis after transient monocular blindness associated with carotid-artery stenosis

Background Transient monocular blindness associated with internal-carotid-artery stenosis is a risk factor for stroke. The effect of carotid endarterectomy in patients who present with transient monocular blindness has not been determined. Methods We compared the risk of stroke among patients presenting with transient monocular blindness with the risk among patients presenting with hemispheric transient ischemic attack. The effect of endarterectomy was assessed in patients with transient monocular blindness. The analyses were based on data from the North American Symptomatic Carotid Endarterectomy Trial. Results A total of 198 medically treated patients with transient monocular blindness had a three-year risk of ipsilateral stroke that was approximately half of that among 417 medically treated patients with hemispheric transient ischemic attack (adjusted hazard ratio, 0.53; 95 percent confidence interval, 0.30 to 0.94). Six factors were associated with a higher risk of stroke in patients with monocular bl...

Prognosis after transient monocular blindness associated with carotid-artery stenosis.

Background Transient monocular blindness associated with internal-carotid-artery stenosis is a risk factor for stroke. The effect of carotid endarterectomy in patients who present with transient monocular blindness has not been determined. Methods We compared the risk of stroke among patients presenting with transient monocular blindness with the risk among patients presenting with hemispheric transient ischemic attack. The effect of endarterectomy was assessed in patients with transient monocular blindness. The analyses were based on data from the North American Symptomatic Carotid Endarterectomy Trial. Results A total of 198 medically treated patients with transient monocular blindness had a three-year risk of ipsilateral stroke that was approximately half of that among 417 medically treated patients with hemispheric transient ischemic attack (adjusted hazard ratio, 0.53; 95 percent confidence interval, 0.30 to 0.94). Six factors were associated with a higher risk of stroke in patients with monocular bl...

Quantitative evaluation of cerebral metabolites and cerebral blood flow in patients with carotid stenosis

We examined the metabolic and hemodynamic status of patients with severe carotid stenosis and evaluated the effectiveness of carotid endarterectomy (CEA) by comparing pre- and post-operative results of quantitative proton magnetic resonance spectroscopy (1H-MRS) and single-photon emission computed tomography (SPECT). Quantitative 1H-MRS and SPECT were performed in 17 patients with severe carotid stenosis before CEA; in 10 patients the examinations were repeated after CEA. There was a significant correlation between the degree of internal carotid artery (ICA) stenosis and the N-acetyl-aspartate (NAA) concentration, and between CBF and NAA in the basal ganglia. In 10 of the 17 patients (58.8%) we noted a decrease of NAA on 1H-MRS. After CEA in these patients, NAA was significantly increased, and in 7 of 8 patients whose pre-operative SPECT had indicated impairment of cerebral vasoreactivity, it was improved. Quantitative 1H-MRS and CBF measurements can indicate the severity of metabolic and hemodynamic impairment in patients with severe carotid stenosis, and can help to assess the effectiveness of CEA. [Neurol Res 2001; 23: 573-580]

Effect of carotid endarterectomy on chronic ocular ischemic syndrome due to internal carotid artery stenosis. Kawaguchi S, Okuno S, Sakaki T, Nishikawa N. Neurosurgery 2001;48:328–333.

Ocular ischemic syndrome, albeit rare, can cause devastating visual dysfunction. The most common cause of chronic ocular hypoperfusion is severe, usually bilateral, carotid artery disease. In this study, 11 patients with various degrees of ocular ischemic syndrome who had hemodynamically-significant ipsilateral carotid artery stenosis (>70% stenosis) were evaluated clinically and with ophthalmic artery color Doppler flow imaging before and after ipsilateral carotid endarterectomy. All patients had minimal or no iris rubeosis. Ophthalmic artery color Doppler flow imaging indicating ophthalmic artery flow direction and peak systolic flow velocity was performed before and at one week, one month, and three months after surgery. Before undergoing carotid endarterectomy, five patients showed reversed ophthalmic artery flow. In the other six patients who experienced antegrade ophthalmic artery flow, the average peak systolic flow velocity was 0.09 ± 0.05 m/s (mean ± standard deviation). Preoperative reversed flow resolved in each patient one week after undergoing surgery. All patients showed antegrade ophthalmic artery flow post-operatively. The average peak systolic flow velocity in the patients who had preoperative antegrade flow rose significantly, to 0.21 ± 0.14 m/s (P < 0.05). These values were still less than the value of the lower limit of the control patients. During the follow-up period (mean, 32.4 months), no patients complained of recurrent visual symptoms. At the end of the study period, visual acuity had improved in five patients and had not worsened in the other six patients. In these 11 patients with nonadvanced disease, carotid endarterectomy was effective in improving or preventing the progress of chronic ocular ischemia related to internal carotid artery stenosis.—Nancy J. Newman

Effect of Carotid Endarterectomy on Chronic Ocular Ischemic Syndrome Due to Internal Carotid Artery Stenosis

Effect of Carotid Endarterectomy on Chronic Ocular Ischemic Syndrome Due to Internal Carotid Artery Stenosis

Acetazolamide SPECT Scans in the Evaluation of Symptomatic and Asymptomatic Patients with Carotid Occlusive Disease

Acetazolamide (ACZ)-enhanced Single Photon Emission Computer Tomography (SPECT) scans can assess both cerebral perfusion and vascular reactivity. Patients with poor reactivity lack perfusion reserve, and are at risk for stroke should perfusion diminish further. This study compared the preoperative ACZ-enhanced SPECT scans of 60 symptomatic to 40 asymptomatic patients with internal carotid artery stenosis (ICAS) in an effort to better define the cause of their symptoms and effects of carotid endarterectomy (CEA) on cerebral perfusion and reactivity in these two groups of patients. Symptomatic patients had at least a 60% (x=84%) ICAS. Asymptomatic patients had at least an 80% (x=90%) ICAS. Preoperative ACZ SPECT scans were obtained usually one week before CEA. All patients underwent CEA. Postoperative ACZ SPECT scans were obtained in 78 of the patients, usually at the first postoperative (-30 days) visit. [Table: see text] Asymptomatic patients demonstrated poorer perfusion than symptomatic patients, which tends to support the premise that most strokes and carotid symptoms are secondary to emboli rather than hypoperfusion. Interestingly, cerebral reactivity was poor in both symptomatic and asymptomatic patients before CEA, suggesting inadequate collaterals and dependency on the ipsilateral carotid. Carotid endarterectomy improved vasoreactivity in 84% of the patients. ACZ SPECT scans provided evidence of the return of cerebral perfusion and reactivity following endarterectomy.

Comparison of Preoperative and Postoperative Duplex Ultrasound Evaluation of the Contralateral Carotid Artery

Duplex ultrasound has become the dominant imaging modality used in the evaluation and preoperative planning for carotid artery stenosis. Numerous studies have addressed the impact of contralateral stenoses on the accurate assessment of ipsilateral disease. Several of these investigators have employed arteriography as a standard of comparison, but this technique is less commonly used and often underestimates the degree of plaque bulk and stenosis. The authors therefore used duplex ultrasound to examine the postprocedural effect of carotid endarterectomy (CEA) on contralateral velocity measurements. They retrospectively reviewed the noninvasive laboratory records of all patients who underwent CEA from January 1996 to August 1998. Inclusion criteria required a preoperative and postoperative scan within 6 months of surgery and patency of both internal carotid arteries. Velocities were expressed in centimeters per second (cm/sec). Results were categorized into groups according to severity of the stenosis (0-49%, 50-79%, 80-99%). Peak systolic and end-diastolic velocities were recorded, and the difference between contralateral velocities before and after surgery was determined. Ipsilateral systolic and diastolic velocities were compared with the contralateral differences. Paired Student's t test and correlation coefficients were employed in the statistical analysis with significance assumed for a p value &lt;0.05. Seventy-nine patients met the study criteria. The preoperative contralateral carotid systolic velocity ranged from 53 to 516 cm/sec and the diastolic velocity from 0 to 182 cm/sec. The contralateral systolic velocity and diastolic velocities did not change after ipsilateral CEA (p=0.59 and p=0.63, respectively). No significant correlation between changes in either contralateral systolic or diastolic velocities and ipsilateral systolic or diastolic velocities were observed (r &lt;0.13 for all comparisons). After CEA, the contralateral carotid changed categories in 10 patients: six decreased from 50-79% to &lt;50% and four increased from &lt;50% to 50-79%. No changes in patient management resulted from these shifts. There is debate over the accuracy of contralateral duplex evaluation of a carotid artery when ipsilateral disease exists. Even after taking into account the severity of the ipsilateral stenosis, we identified no statistical difference in measured contralateral velocities after CEA. Duplex ultrasound appears to provide an accurate assessment of carotid artery stenosis even in bilateral disease.