Carotid endarterectomy without angiography: can clinical evaluation and duplex ultrasonographic scanning alone replace traditional arteriography for carotid surgery workup? A prospective study

Duplex ultrasound for diagnosing symptomatic carotid stenosis in the extracranial segments

BACKGROUND

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

OBJECTIVES

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

SEARCH METHODS

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included studies and other relevant publications and contacted experts in the field to identify additional studies or unpublished data.

SELECTION CRITERIA

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

DATA COLLECTION AND ANALYSIS

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

MAIN RESULTS

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

AUTHORS' CONCLUSIONS

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

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

INTRODUCTION

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

CASE OUTLINE

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

CONCLUSION

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

Carotid artery velocity characteristics after carotid artery angioplasty and stenting

OBJECTIVE

Correlation of carotid duplex ultrasound (DUS) flow velocities with carotid artery stenosis before and after carotid endarterectomy is well established. With the evolution of catheter-based techniques, carotid stenosis increasingly is being treated with angioplasty and stenting (CAS). CAS changes the physical properties of the arterial wall, which may alter blood flow velocities compared with the nonstented carotid. Opinions differ about whether DUS is a reliable tool to assess technical outcome and recurrent stenosis after CAS. This study correlated carotid DUS flow velocity findings with carotid arteriography after CAS.

METHODS

Data from 77 pairs of carotid arteriograms with corresponding DUS after CAS in 68 patients were reviewed. Preintervention and postintervention DUS and carotid arteriogram data were evaluated for each patient. Peak systolic velocities (PSV), end-diastolic velocities (EDV), and internal carotid artery/common carotid artery ratios (ICA/CCA) were correlated with the post-CAS arteriogram.

RESULTS

The mean preintervention PSV was 390 +/- 110 cm/s (range, 216 to 691 cm/s), and the average EDV was 134 +/- 51 cm/s (range, 35 to 314 cm/s). Postintervention DUS was obtained a mean of 5 days after CAS (range, 1 to 30 days). Sixty (81%) post-CAS arteriograms were normal, and each corresponded to a normal postintervention DUS (PSV range, 30 to 118 cm/s; EDV range, 18 to 60 cm/s). In 14 arteries (19%), completion arteriograms revealed residual stenoses of 20% to 40% in 13, and 50% in one. The mean PSV was 175 cm/s (range, 137 to 195 cm/s), and the mean EDV was 44 cm/s (range, 20 to 62 cm/s). All velocities exceeded the threshold of a 50% stenosis by DUS criteria for a nonstented carotid artery. In three arteries (2 patients), high-grade recurrent stenoses detected by DUS developed that required reintervention during follow-up. This high-grade restenosis was confirmed by arteriography in each patient, providing an additional three correlations.

CONCLUSIONS

Normal DUS imaging reliably identifies arteriographically normal carotid arteries after CAS. Carotid velocities are disproportionately elevated with mild and moderate degrees of stenoses, and velocity criteria for quantitating stenoses in these patients require modification. However, DUS appropriately identifies severe recurrent stenoses after CAS.

Progression of atherosclerosis in asymptomatic carotid arteries after contralateral endarterectomy: a 10-year prospective study

OBJECTIVE

The best way to manage both symptomatic and asymptomatic severe carotid stenoses has been thoroughly demonstrated by large randomized clinical trials, but less is known about the natural history and management of the contralateral asymptomatic internal carotid artery (ICA). This prospective study was undertaken to determine whether disease progressed in the contralateral ICA of patients who had undergone carotid endarterectomy (CEA) and were followed up clinically and by duplex ultrasound (US) scan.

METHODS

The contralateral asymptomatic ICAs of 599 patients who had undergone CEA for severe carotid disease over a 10-year period were followed up clinically and with duplex US scan at 1 month and then every 6 months. ICA stenosis was classified as mild (30%-49%), moderate (50%-69%), severe (70%-99%), or occlusion. Progression was defined as an increase in ICA stenosis of 50% or more for ICAs with a less than 50% baseline lesion or as an increase to a higher category if the baseline stenosis was 50% or more. End points of the study were the incidence of contralateral disease progression and late neurologic events. Kaplan-Meier analysis was used to estimate freedom from disease progression and from neurologic events. The relationship between progression and risk factors was also analyzed.

RESULTS

Overall, disease progressed in 25.2% of patients (151/599) after a mean follow-up of 4.1 years. Disease progressed in 34.3% of patients (101/294) with mild stenosis vs 47.9% of patients with moderate stenosis (47/98; P = .016). Three additional patients with mild lesions at baseline progressed to severe lesions. The median time to progression was 29.8 months for mild and 18.5 months for moderate stenoses (P = .033). The rate of late neurologic events referable to the contralateral ICA was 3.2% (19/599) for the entire series and 4.8% (19/392) for patients with a 30% or greater ICA stenosis: these included 4 (0.7%) strokes and 15 (2.5%) transient ischemic attacks. All but 3 events (16.3%; 16/98) occurred in patients with disease progression from moderate to severe stenosis. Overall, 53 late CEAs were performed.

CONCLUSIONS

This prospective analysis has shown that disease progression in contralateral asymptomatic ICAs after CEA is relatively common in patients with a diseased ICA at the baseline and strongly supports duplex US surveillance, approximately every 6 months, in patients with more than mild disease. A baseline lesion is significantly predictive of progression to severe stenosis, and progression from moderate to severe stenosis is strongly associated with neurologic clinical events. No demographic or clinical factor proved useful in identifying patients likely to experience disease progression.

Duplex Ultrasound Verified by Angiography in Patients with Severe Primary and Restenosis of Internal Carotid Artery

There are very limited data in the literature about the reliability of duplex ultrasound (DU) verified by angiography in patients with restenosis of the internal carotid artery (ICA) after carotid surgery compared with primary carotid artery stenosis patients. Our objective was to compare the reliability of DU verified by conventional angiography in the diagnosis of severe primary stenosis versus restenosis of ICA. One hundred thirty-four patients (238 arteries) were examined by both DU and angiography. Severe stenosis (>70%) was found in 47 primary stenotic arteries and in 70 restenotic arteries. Accuracy, specificity, sensitivity, positive predictive value (PPV), and negative predictive value were obtained for basic DU criteria after verification of ultrasound data by angiography. The best accuracy for detection of >70% stenosis by end diastolic velocity was found for the velocity of 70 cm/sec or more in both groups, but accuracy for the restenosis group was significantly higher (96.9% vs. 89.8%, p = 0.025). Additionally, specificity (p = 0.01) and PPV (p = 0.01) were significantly higher in the restenosis group. The best accuracy for detection of >70% stenosis by peak systolic velocity was found for the velocity of 220 cm/sec or more for restenoses and 200 cm/sec or more for primary stenoses. The accuracy of the ultrasound was significantly higher in the restenosis group (94.6% vs. 87%, p = 0.04), as were specificity (p = 0.01) and PPV (p = 0.02). The diagnosis of severe restenosis by DU is reliable and can be used for decision making regarding surgery or stenting without angiography. In patients with Doppler parameters pointing to borderline moderate/severe primary carotid stenosis and technically complicated cases, angiography in addition to sonography before surgery is recommended.

Cerebral hemodynamics after contralateral carotid endarterectomy in patients with symptomatic and asymptomatic carotid occlusion: a 10-year follow-up

We sought to investigate whether carotid endarterectomy (CEA) can achieve long-term cerebral hemodynamic improvement and reduce recurrence of cerebral ischemic events in symptomatic and asymptomatic patients with severe (>70%) carotid artery stenosis contralateral to carotid occlusion (CO). Thirty-nine patients with severe carotid lesion contralateral to CO were studied before (1 day) and after CEA (at 7 days, 1, 3 and 6 months, and then yearly thereafter). Collateral flow and cerebral vasomotor reactivity (VMR) were assessed by transcranial Doppler sonography (TCD). A total of 32 unoperated patients with severe carotid lesion contralateral to CO, who were comparable with respect to age and sex, served as a control group. The average period of TCD follow-up was 10 years and was obtained in all patients; during this period, major clinical events (stroke, acute myocardial infarction and death) were also recorded. The proportion of patients with collateral flow via the anterior communicating artery increased significantly from 61.5% before to 89.7% after CEA (P = 0.01). Cerebral VMR ipsilateral to CO improved in 85.7% of patients (30 of 35) within 30 days of CEA, and in all patients within 90 days. No significant spontaneous VMR recovery was recorded in the control group. After the initial recovery, no significant change in VMR was observed in the surgical group or the control group during the follow-up. In conclusion, in patients with severe carotid stenosis, CEA contralateral to symptomatic and asymptomatic CO determines a durable cerebral hemodynamic improvement not only on the side of the CEA but also on the contralateral side, with no difference between symptomatic and asymptomatic patients.

High-grade symptomatic and asymptomatic carotid stenosis in the very elderly. A challenge for proponents of carotid angioplasty and stenting

Background

Carotid angioplasty and stenting (CAS) is often considered as the preferred treatment for severe carotid occlusive disease in patients labelled as "high risk", including those aged 80 or more. We analyzed 30-day stroke risk and death rates after carotid endarterectomy (CEA) for severe symptomatic or asymptomatic carotid disease in patients aged 80 or more, by comparison with the outcome of CAS reported in the recently- published literature.

Methods

A retrospective review was conducted on a prospectively compiled computerized database of all primary CEAs performed by a single surgeon at our institution from 1990 to 2003. Descriptive demographic data, risk factors, surgical details, perioperative strokes and deaths, and other complications were recorded.

Results

In all, 1260 CEAs were performed in 1099 patients; 1145 were performed in 987 patients less than 80 years old, and 115 were performed in 112 patients aged 80 or more. There were 11 perioperative strokes in the 1145 procedures in the younger group, for a stroke rate of 0.8%, and no strokes in the 115 procedures in the older group. The death rates were 0% for the octogenarians and 0.3% for the younger group.

Conclusion

The conviction that older age means higher risk needs to be revised. Patients aged 80 or more can undergo CEA with no more perioperative risks than younger patients. Proponents of CAS should bear this in mind before recommending CAS as the best therapeutic option for such patients.

Extracranial Severe Carotid Stenosis and Incidental Intracranial Aneurysms

Among 474 patients having 547 carotid endarterectomies (CEAs) over an 80-month period, 11 (2.3%) with symptomatic (n = 8) and asymptomatic (n = 3) severe (>70%) carotid stenosis had 12 asymptomatic intracranial aneurysms (IAs). None had postoperative stroke or died, and none had surgical or endovascular IA treatment before or after CEA. In an average 5-year follow-up, no patients had subarachnoid hemorrhage. Having an IA does not seem to be an additional risk factor for CEA, nor does CEA seem to increase the chance of IA rupture.

Is carotid duplex scanning sufficient as the sole investigation prior to carotid endarterectomy?

Carotid endarterectomy (CEA) is the accepted treatment for certain patients who have had, or who are at risk of having, a stroke if they have a significant narrowing of the internal carotid artery. Rapid and accurate classification of the degree of stenosis is important as the benefit of surgery is highly dependent on this. The aim of this study was to assess whether the addition of angiography to duplex scanning resulted in a change in patient management in a unit where duplex scanning was used as the sole imaging investigation prior to CEA. The study population consisted of 64 patients with significant internal carotid artery stenosis on duplex scanning who were suitable for, and wished to be considered for, CEA. All patients underwent an angiogram. In this study 9 (14%) patients did not proceed to surgery on the basis of angiography and in a further 11 (17%) patients insufficient views of the distal vessel were obtained on duplex scanning. Three of these patients had extensive disease which excluded surgery. One patient experienced a transient ischaemic attack (TIA) at the time of angiography. In conclusion, this audit has highlighted the limitations in performing duplex scanning alone, and the costs that this can incur on the patient who may undergo an unnecessary operation. We cannot recommend duplex scanning as the sole investigation prior to CEA. There is need to evaluate the role of additional non-invasive carotid imaging such as magnetic resonance angiography or CT angiography in the assessment of these patients.

Prospective Randomized Study on Asymptomatic Severe Carotid Stenosis and Perioperative Stroke Risk in Patients Undergoing Major Vascular Surgery: Prophylactic or Deferred Carotid Endarterectomy?

We compared the perioperative (30-day) stroke risk in asymptomatic patients with severe carotid stenosis who underwent carotid endarterectomy (CEA) before or after major vascular surgery. Seventy-nine patients with asymptomatic severe carotid lesion were randomly assigned to group I (n = 40) or group II (n = 39) to receive prophylactic CEA (within 1 week before major surgery) or deferred CEA (between 30 days and 6 months after major surgery), respectively. All procedures were eversion CEAs performed under deep general anesthesia and cerebral protection involving continuous electroencephalographic monitoring for selective shunting. There were no perioperative deaths or strokes relating to the major surgical procedure in either group. All group II patients underwent deferred CEA as planned (median 47 days, range 38-94) with no subsequent perioperative deaths or strokes. Two of these patients (5.1%) suffered a minor stroke, however, 65 and 78 days after their major surgical procedure, while awaiting carotid revascularization. Although data emerging from this analysis indicate that severe asymptomatic carotid disease may be safely postponed in patients undergoing major noncarotid vascular surgery, only a multicenter prospective study could determine the most appropriate management of this subset of patients.

Ultrasonographic confirmation of carotid artery atheromas diagnosed via panoramic radiography

BACKGROUND

Studies have shown that panoramic radiographs can capture images of calcified atheromas in the internal carotid artery (ICA) in some neurologically asymptomatic patients receiving routine dental care. However, the prevalence of these hemodynamically significant lesions--that is, those causing greater than 50 percent vessel lumen occlusion with the consequent heightened risk of stroke--has been evaluated rarely. The purpose of this study was to use Doppler ultrasonography (DUS) to determine the prevalence of large occlusive lesions detected initially via panoramic radiography. Aggressive medical and surgical interventions directed toward these large lesions have been shown to moderate the risk of stroke.

STUDY DESIGN

The authors analyzed the panoramic radiographs of 1,548 consecutively treated, neurologically asymptomatic dental patients who were 50 years or older. Those with presumptive atheromas underwent DUS for confirmation of the diagnosis and for determination of the degree of stenosis.

RESULTS

The radiographs of 65 patients (4.2 percent) showed at least one ICA atheroma. Thirty-eight patients had bilateral opacities and 27 had unilateral opacities. DUS evaluation of the 103 sides of the neck with a radiographically identified atheroma revealed that none of the ICAs were normal, 81 (79 percent) had less than 50 percent stenosis, 18 (17 percent) had 50 to 69 percent stenosis and four (4 percent) had 70 percent or greater stenosis. Four of the ICAs on the 27 sides without calcifications were deemed normal and 23 had less than 50 percent stenosis.

CONCLUSIONS

These results demonstrate that a subset of patients (15 [23 percent] of 65) with an occult atheroma discovered on panoramic radiography had significant (> 50 percent) levels of ICA stenosis.

CLINICAL IMPLICATIONS

Dentists should refer all patients with radiographically identified atheromas to a physician for confirmation of the diagnosis and a determination of the magnitude of disease, because antiatherogenic interventions have been shown to prevent a stroke.

Carotid Endarterectomy: Experience in 5425 Cases

From 1992 to December 2002, 3967 patients (2619 males; 1348 females) with a mean age of 68.4A years (range 32-92) underwent 5425 carotid endarterectomy (CE) procedures at our institute. Neurological history was positive for stroke in 1130 cases (21%) and for transient ischemic attack (TIA) in 2121 cases (39%). In 2174 cases (40%) patients were neurologically asymptomatic or presented nonspecific symptoms. Our current clinical protocol has been designed to optimize resources and reduce complications. Some of the major features, along with the respective percentages in this series, are as follows. Duplex scanning was performed at a validated laboratory as the principal preoperative exam (86.9%). Locoregional anesthesia and neurological monitoring were performed during carotid cross-clamping (96.3%). Selective shunting was carried out with a Javid shunt (10.7%). The choice of surgical technique was made according to carotid anatomy and cerebral tolerance of cross-clamping. Those used were a standard technique (now abandoned, 12.1%), synthetic patching (46.4%), and eversion endarterectomy (41.5%). Intraoperative completion arteriography was routinely performed for eversion endarterectomy and only in dubious cases with other techniques. The option of staying in an postoperative intensive care unit (ICU) was available (selective use, 2%). In uncomplicated cases, early discharge (after 1.5 postoperative days) was considered safe. The overall perioperative mortality was 0.37% (20/5425). Causes of death were myocardial infarction in seven cases, ischemic stroke in six cases, hemorrhagic stroke in five cases, respiratory failure caused by cervical hematoma in one case, and wound infection in one case. Perioperative neurological morbidity was 1.31% (71/5425); there were 43 major and 28 minor strokes. In conclusion, CE is effective for stroke prevention when there is significant symptomatic and asymptomatic carotid stenosis, as low mortality and morbidity may be achieved in an experienced center. At our institute, the reduction of costs did not have negative consequences on the quality of the surgical care.

Durability of carotid endarterectomy for treatment of symptomatic and asymptomatic stenoses

PURPOSE

Although many studies have well established that carotid endarterectomy (CEA) is beneficial in selected patients with severe carotid disease, only a few large studies have focused on the durability of the surgical procedure. Carotid artery angioplasty and stenting (CAS) has recently been proposed as a potential alternative to CEA. We analyzed the incidence of late occlusion and recurrent stenosis after CEA.

METHODS

Over 13 years 1000 patients underwent 1150 CEA procedures to treat symptomatic and asymptomatic high-grade carotid stenosis. CEA procedures involving either traditional CEA with patching (n = 302) or eversion CEA (n = 848) were all performed by the same surgeon, with patients under deep general anesthesia and cerebral protection involving continuous electroencephalographic monitoring for selective shunting. All patients underwent postoperative duplex ultrasound scanning and clinical follow-up at 1, 6, and 12 months, and yearly thereafter. New neurologic events, late occlusions, and recurrent stenoses 50% or greater were recorded. Complete follow-up (mean, 6.2 years; range, 6-156 months) was obtained in 95% of patients (949 of 1000), for an overall average of 95% of procedures (1092 of 1150). Survival analysis was performed with the Kaplan-Meier life table method.

RESULTS

Perioperative (30-day) mortality rate was 0.3% (3 of 1000), and stroke rate was 0.9% (11 of 1150), with a combined mortality and stroke rate of 1.2%. The incidence of late occlusion and recurrent stenosis 70% or greater was 0.6% and 0.5%, respectively, with a combined occlusion and restenosis rate of 1.1%. Kaplan-Meier analysis showed that the rate of freedom from occlusion, restenosis 70% or greater, and combined occlusion and restenosis 70% or greater at 12 years was 99,4%, 99.5%, and 98.8%, respectively. Occlusion and restenosis developed asymptomatically.

CONCLUSIONS

CEA is a low-risk procedure for treating severe symptomatic and asymptomatic carotid disease, with excellent long-term durability. Proponents of CAS should bear this in mind before considering CAS as a routine alternative to CEA.

Selective shunting with eversion carotid endarterectomy

PURPOSE

The consensus is that eversion carotid endarterectomy (CEA) is a safe, effective, and durable surgical technique. Concern remains, however, regarding insertion of a shunt during the procedure. We studied the advisability of shunting with eversion CEA by comparing patients who underwent eversion CEA with and without shunting.

METHODS

Over 9 years, 624 primary eversion CEAs were performed in 580 selected patients to treat symptomatic (n = 398, 63.8%) and asymptomatic (n = 226, 36.2%) carotid lesions. All eversion CEAs were performed by the same surgeon (E.B.), with the patient under deep general anesthesia, with continuous electroencephalographic (EEG) monitoring for selective shunting, based exclusively on EEG changes consistent with cerebral ischemia. A Pruitt-Inahara shunt was used in 43 eversion CEAs (6.9%). All patients underwent postoperative duplex ultrasound scanning and clinical follow-up at 1, 6, and 12 months and once a year thereafter. Mean follow-up was 52 months (range, 3-91 months). The main end points were perioperative (30-day) stroke and death, and recurrent stenosis.

RESULTS

No perioperative death occurred in this series. Overall, ischemic perioperative stroke occurred in 4 of 624 patients (0.6%). Two strokes were minor and two were major. Only one (major) stroke occurred in the group with shunt insertion (1 of 43, 2.3%; P = not significant); the everted internal carotid artery was patent. Long-term follow-up was performed in all living patients. There was no late recurrent stenosis (>50%), and one late asymptomatic occlusive event occurred in the group without shunt insertion.

CONCLUSIONS

Shunt insertion can be safely performed during eversion CEA. Perioperative mortality and morbidity after eversion CEA are not statistically modified with shunting.

Carotid endarterectomy then and now: outcome and cost-effectiveness of modern practice

BACKGROUND

During the past decade, our practice of performing carotid endarterectomy (CEA) has changed dramatically, most notably by an abrupt shift from routine to selective preoperative angiography, reliance on defined care plans with full-time nurse practitioner oversight, and increasing reliance on eversion endarterectomy and cervical block anesthesia. This study was designed to determine whether these shifts in policy have been associated with lower costs without sacrificing clinical outcome.

METHODS

All patients undergoing CEA from July 1993 to December 2000 were identified, and inpatient and outpatient charts were reviewed. Cost data were obtained from the central hospital accounting system and converted to 2001 dollars. Thirty-day outcomes and costs were quantified each year and compared between each of 2 temporally well-defined groups: those undergoing "routine" versus "selective" angiography and those cared for before and after defined patient care protocols were instituted.

RESULTS

A total of 1168 CEAs were analyzed. Thirty-day combined stroke and death rate was 3.1%, and no trends or significant differences over time were seen. From 1993 to 2000 the cost of CEA fell from $9302 to $6216 (P<.0002), and length of stay was reduced 1 full day (P=.005). Institution of "selective" angiography was associated with an immediate cost savings of approximately $2000 per case (P<.0001), and nurse practitioner oversight along with institution of defined clinical protocols with a $530 (P<.05) decline in nonoperating room-related costs.

CONCLUSIONS

Changes in policy from routine to selective angiography, reliance on defined postoperative care pathways, eversion endarterectomy, and cervical block anesthesia have been associated with significant cost savings, with no compromise in clinical outcome at our institution.

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

BACKGROUND AND PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Carotid Eversion Endarterectomy: Perioperative Outcome and Restenosis Incidence

Carotid endarterectomy (CEA) for stroke prevention can be performed with minimal perioperative mortality and morbidity rates. The type of surgical technique used is important to achieve optimal outcome from CEA. The purpose of this study was to analyze the perioperative and late results of carotid eversion endarterectomy (CEE) in more than 400 procedures. From August 1992 to December 1999, 402 primary CEEs were performed in 388 selected patients for symptomatic (235/58.4%) and asymptomatic (167/41.6%) carotid lesions. During the same period, 234 primary CEAs with patch closure were performed in 229 selected patients. All CEAs were carried out with continuous electroencephalographic monitoring for selective shunting, using deep general anesthesia. All patients underwent postoperative duplex ultrasound study and clinical follow-up at 1, 6, and 12 months and every year thereafter. The mean follow-up was 50 months (range 3-88). Main end points were perioperative stroke and death, and restenosis. Our results showed that use of the CEE procedure can reduce perioperative mortality and stroke risk rates to around zero and results in no restenosis.

Critical review of non- or minimally invasive methods (duplex ultrasonography, MR- and CT-angiography) for evaluating stenosis of the proximal internal carotid artery

OBJECTIVE

to assess the performance of non- or minimally invasive methods (duplex ultrasonography, MR- and CT-angiography) in measuring stenosis of the proximal internal carotid prior to endarterectomy without preoperative intra-arterial digital subtraction angiography (DSA).

METHODS

systematic review of the literature (five databases, 1990 to February 2001). The value of each imaging technique was studied through its reproducibility and its sensitivity/specificity compared to DSA.

RESULTS

sensitivity exceeded 80% and specificity 90% in over two-thirds of the methodologically sound studies, regardless of technique, although direct comparisons between results had to be avoided since the findings originated from different populations. The main drawback of duplex ultrasonography is its levels of reproducibility. In contrast, only a few studies have addressed the reproducibility of MR- and CT-angiography. When the results of duplex and MR-angiography agree, the combination use of these two techniques provides a better diagnosis than either technique taken alone.

CONCLUSIONS

all three techniques appear suitable for measuring stenosis of the proximal internal carotid when compared to DSA.

Is diabetes mellitus a risk factor for carotid endarterectomy? A prospective study

BACKGROUND

Although many randomized trials and other multicenter studies have demonstrated the benefits of carotid endarterectomy (CEA) in selected symptomatic and asymptomatic patients, several investigators have noted an increased rate of perioperative neurologic and cardiac morbidity in diabetic patients. To compare the perioperative outcome of CEA in diabetic patients (group I) versus nondiabetic patients (group II), we analyzed a consecutive series of CEAs performed by the same vascular surgeon at the same institution.

METHODS

Data collection was prospective for all CEA procedures performed between August 1, 1992 and March 31, 1999. Group I and group II were matched for clinical presentation, percentage of internal carotid artery stenosis and indication for surgery.

RESULTS

of 547 CEAs performed in 474 patients, 199 (36.4%) were in group I. Group I was younger at presentation than group II (P <.005) and women were in a higher proportion in group I than in group II (43.7% vs 27.1%, P =.0001). Although the incidence of peripheral atherosclerotic disease was comparable in the 2 groups, there was a significantly higher incidence of previous vascular surgery in group I (P =.01). Perioperative neurologic and cardiac morbidity rates were comparable in the 2 groups. The overall perioperative mortality rate was 0.5%. Long-term information was obtained in all patients (mean, 44 months; range, 1 to 75 months). No differences were found in the recurrent stenosis and occlusion rates between the 2 groups. Although there was no difference in the late mortality between the 2 groups, diabetic patients had a significantly higher cardiac-related death incidence (P =.01) than nondiabetic patients.

CONCLUSIONS

The findings of this analysis indicate that CEA can be performed in diabetic patients with excellent perioperative morbidity and mortality rates and late stroke-free and survival rates that are comparable with those recorded in nondiabetic patients.

A prospective randomized study on bilateral carotid endarterectomy: patching versus eversion

OBJECTIVE

To compare the clinical outcome and restenosis incidence of patients who underwent carotid endarterectomy with patch closure (CEAP) on one side and carotid eversion endarterectomy (CEE) on the other.

SUMMARY BACKGROUND DATA

Although a few investigators have compared the results of CEAP versus CEE, no reports have compared the outcome of CEAP versus CEE in the same patient.

METHODS

Eighty-six patients were randomly selected for sequential surgical treatment involving either CEAP/CEE or CEE/CEAP. All patients underwent postoperative duplex ultrasound study and clinical follow-up at 1, 6, and 12 months and every year thereafter. Various factors were analyzed to ascertain any association with restenosis, and Kaplan-Meier analysis was used to estimate the risk of restenosis.

RESULTS

Demographic and clinical data were similar in the CEAP and CEE groups. The selective shunting rate was statistically higher in the CEAP group. There were no perioperative deaths. Although the incidence of perioperative ipsilateral stroke was not significant, CEAP patients had a rate of combined transient ischemic attacks and strokes that approached statistical significance. The mean follow-up was 40 months. CEAP patients had a significantly higher incidence of restenosis and combined occlusive events and restenoses. Kaplan-Meier analysis showed that CEE had a significantly better cumulative patency rate than CEAP and that freedom from restenoses at 24 and 36 months was 87% and 83% for CEAP and 98% and 98% for CEE, respectively.

CONCLUSIONS

CEE is less likely to cause perioperative neurologic complications and restenoses than CEAP. The significantly higher rate of unilateral recurrence suggests that local factors play a more important role than systemic factors in the occurrence of restenosis.