Carotid endarterectomy without angiography does not compromise operative outcome

Carotid Endarterectomy for Asymptomatic Stenosis Based on Duplex Ultrasound Alone Achieves Equivalent Perioperative and Long-Term Outcomes Relative to Advanced Imaging Based Endarterectomy

BACKGROUND

The purpose of this study is to compare both perioperative as well as long-term outcomes of patients undergoing carotid endarterectomy (CEA) for asymptomatic carotid bifurcation stenosis based on duplex ultrasound in isolation relative to a combination of duplex and more advanced imaging.

METHODS

All CEA in the VQI between January 2003 and May 2022 were queried. We identified 171,816 CEAs in the database. Exclusions were symptomatic carotid lesion (57,742), lack of imaging documentation (908), lack of advanced imaging status (1,816), simultaneous additional arterial intervention in the carotid, coronary, or peripheral arterial system (n = 4,118), and anatomic high-risk status for CEA (n = 4,071). Included patients were then placed into 1 of 2 cohorts: patients undergoing CEA based on duplex imaging alone (n = 33,437) and those undergoing CEA based on advanced imaging (CTA, MRA, or invasive angiography) with or without duplex (n = 69,715). We performed multivariable analysis for the following outcomes utilizing CEA based on duplex in isolation as 1 of the variables: perioperative neurological ischemic event utilizing binary logistic regression; combined 90-day mortality and neurological ischemic event utilizing binary logistic regression; neurological event in long-term follow-up with date of surgery serving as time zero; time dependent Cox regression analysis; mortality in long-term follow-up utilizing time-dependent Cox regression.

RESULTS

Carotid endarterectomy based on duplex alone and CEA based on advanced imaging had essentially equivalent rates of 90-day mortality (0.9% vs. 1.0%, P = 0.108); combined perioperative neurological event and 90-day mortality (2.0% vs. 2.2%, P = 0.042); and, return to the operating room (1.6% vs. 1.7%, P = 0.154). On multivariable analysis CEA based on advanced imaging was noted to have a slightly higher absolute rate of perioperative neurological event without achieving multivariable significance (1.3% vs. 1.2%, adjusted odds ratio 1.11 (0.98-1.25), P = 0.092. CEA based on advanced imaging had a higher rate of neurological event after index hospital admission relative to duplex in isolation (hazard ratio (HR) 1.44 (1.31-1.60), P < 0.001). However, the absolute percentage difference was just 0.5% (1.6% vs. 2.1%). CEA based on duplex alone was associated with a slightly increased risk of mortality in LTFU (HR 1.16 (1.11-1.21), P < 0.001). At 5 years the absolute risk of mortality was less than 1% different between the cohorts.

CONCLUSIONS

Performing CEA for asymptomatic bifurcation stenosis based on duplex ultrasound alone is a safe practice which achieves clinically equivalent perioperative and long-term freedom from cerebral ischemia and mortality relative to CEA based on advanced imaging. This has potential implications for health care cost saving as well as avoidance of radiation and iodinated contrast.

SOCIETY FOR VASCULAR SURGERY CLINICAL PRACTICE GUIDELINES FOR MANAGEMENT OF EXTRACRANIAL CEREBROVASCULAR DISEASE

Management of carotid bifurcation stenosis in stroke prevention has been the subject of extensive investigations, including multiple randomized controlled trials. The proper treatment of patients with carotid bifurcation disease is of major interest to vascular surgeons and other vascular specialists. In 2011, the Society for Vascular Surgery published guidelines for treatment of carotid artery disease. At the time, several randomized trials, comparing carotid endarterectomy (CEA) and carotid artery stenting (CAS), were published. Since that publication, several studies and a few systematic reviews comparing CEA and CAS have been published, and the role of medical management has been re-emphasized. The current publication updates and expands the 2011 guidelines with specific emphasis on five areas: is carotid endarterectomy recommended over maximal medical therapy in low risk patients; is carotid endarterectomy recommended over trans-femoral carotid artery stenting in low surgical risk patients with symptomatic carotid artery stenosis of >50%; timing of carotid Intervention in patients presenting with acute stroke; screening for carotid artery stenosis in asymptomatic patients; and optimal sequence for intervention in patients with combined carotid and coronary artery disease. A separate implementation document will address other important clinical issues in extracranial cerebrovascular disease. Recommendations are made using the GRADE (Grades of Recommendation Assessment, Development and Evaluation) approach, as has been done with other Society for Vascular Surgery guidelines. The committee recommends CEA as the first-line treatment for symptomatic low risk surgical patients with stenosis of 50% to 99% and asymptomatic patients with stenosis of 70% to 99%. The perioperative risk of stroke and death in asymptomatic patients must be <3% to ensure benefit for the patient. In patients with recent stable stroke (modified Rankin 0-2), carotid revascularization is considered appropriate in symptomatic patients with greater than 50% stenosis and is recommended and performed as soon as the patient is neurologically stable after 48 hours but definitely before 14 days of onset of symptoms. In the general population, screening for clinically asymptomatic carotid artery stenosis in patients without cerebrovascular symptoms or significant risk factors for carotid artery disease is not recommended. In selected asymptomatic patients who are at increased risk for carotid stenosis, we suggest screening for clinically asymptomatic carotid artery stenosis as long as the patients would potentially be fit for and willing to consider carotid intervention if significant stenosis is discovered. In patients with symptomatic carotid stenosis 50-99%, who require both CEA and CABG, we suggest CEA before or concomitant with CABG to potentially reduce the risk of stroke and stroke/death. The sequencing of the intervention depends on clinical presentation and institutional experience.

Carotid near-occlusion frequently has high peak systolic velocity on Doppler ultrasound

PURPOSE

Carotid near-occlusion is a tight atherosclerotic stenosis of the internal carotid artery (ICA) resulting in decrease in diameter of the vessel lumen distal to the stenosis. Near-occlusions can be classified as with or without full collapse, and may have high peak systolic velocity (PSV) across the stenosis, mimicking conventional > 50% carotid artery stenosis. We aimed to determine how frequently near-occlusions have high PSV in the stenosis and determine how accurately carotid Doppler ultrasound can distinguish high-velocity near-occlusion from conventional stenosis.

METHODS

Included patients had near-occlusion or conventional stenosis with carotid ultrasound and CT angiogram (CTA) performed within 30 days of each other. CTA examinations were analyzed by two blinded expert readers. Velocities in the internal and common carotid arteries were recorded. Mean velocity, pulsatility index, and ratios were calculated, giving 12 Doppler parameters for analysis.

RESULTS

Of 136 patients, 82 had conventional stenosis and 54 had near-occlusion on CTA. Of near-occlusions, 40 (74%) had high PSV (≥ 125 cm/s) across the stenosis. Ten Doppler parameters significantly differed between conventional stenosis and high-velocity near-occlusion groups. However, no parameter was highly sensitive and specific to separate the groups.

CONCLUSION

Near-occlusions frequently have high PSV across the stenosis, particularly those without full collapse. Carotid Doppler ultrasound does not seem able to distinguish conventional stenosis from high-velocity near-occlusion. These findings question the use of ultrasound alone for preoperative imaging evaluation.

Comparison of Doppler ultrasound velocity parameters in the determination of internal carotid artery stenosis

This study aims to compare the evidence base and practical results of the Joint Recommendations for Reporting Carotid Ultrasound Investigations in UK, published in 2009, and existing carotid scan protocols based on the Society of Radiologists in Ultrasound 2003 Consensus. A prospective sequential evaluation of the 2009 recommendations was performed at the University Hospital of Wales, Cardiff. Additional measurements in line with the recommendations were made during carotid scans. The grading of internal carotid artery stenosis using the 2003 and 2009 UK recommendations, and recommended measures of PSV, PSV ratio and St Mary’s ratio were compared. In comparison to PSV classification, PSV ratio produced lower stenosis classification in 29% and 24% of cases in the 50–69% and 70–89% stenosis bands respectively. St Mary’s ratio produced poor classification agreement across all bands, particularly the 50%–69% stenosis band. Agreement of two measures is recommended for diagnostic confidence; however, in the 50%–69% and 70%–89% stenosis bands, agreement of two measures only occurred in 70% of scans. This evaluation suggests that the use of three measurements in the 2009 recommendations complicates rather than aids diagnosis, especially in the 50%–69% and 70%–89% stenosis bands, and does not provide significant improvement over the 2003 guidelines. No evidence was found to support the combined use of the three measures.

Assessing the quality of surgical care in vascular surgery; moving from outcome towards structural and process measures

OBJECTIVES

This study presents a review of studies reporting on quality of care in vascular surgery. The aim of this study was to provide insight in quality improvement initiatives in vascular surgery.

DESIGN

Original data were collected from MEDLINE and EMBASE databases. Inclusion criteria were: description of one of the three factors of quality of care, e.g. process, outcome or structure and prospectively described. All articles identified were ascribed to a domain of quality of care.

RESULTS

57 prospective articles were included, drawn from 859 eligible reports. Structure as an indicator of quality of care was described in 19 reports, process in 7 reports and outcome in 31 reports. Most studies based on structural measures considered the introduction of a clinical pathway or a registration system. Reports based on process measures showed promising results. Outcome as clinical indicator mainly focussed on identifying risk factors for morbidity, mortality or failure of treatment.

CONCLUSIONS

Structure and process indicators are evaluated scarcely in vascular surgery. Many studies in vascular surgery have been focussed on outcomes as indicator of quality of care, but a shift towards process measures should be considered as focus of attention in the future.

Carotid endarterectomy performed in the morning is associated with increased cerebral microembolization

OBJECTIVES

Platelet function exhibits circadian variation with highest levels of activity in the morning and plays a central role in arterial thrombotic events, including thrombotic stroke following carotid endarterectomy (CEA). Prior to the platelet-rich thrombus occluding the carotid artery, multiple embolic signals are detected in the middle cerebral artery using transcranial Doppler ultrasound. We hypothesized that patients undergoing CEA early in the day may be at an increased stroke risk and this would manifest as an increased postoperative embolic count.

METHODS

Data were collected prospectively on 235 patients undergoing primary CEA. Accurate start and finish times were recorded in addition to the number of postoperative emboli detected in the first three hours after CEA using transcranial Doppler (TCD) monitoring.

RESULTS

For operations finishing before midday, there was a 3.6-fold increase in the number of emboli detected relative to afternoon finishes (53.2 vs 14.8, P = .002) with similar results for starts before 10:30 AM (48.1 vs 14.7, P =.002). There was also a significant correlation between start time and emboli count (P = .02). Of the 55 patients with no postoperative emboli, only 19 had a morning start (relative risk 0.63, P = .011). Patients were 6.9 times more likely to require treatment with Dextran-40 to prevent progression onto a thrombotic stroke if their CEA finished before midday (P = .008).

CONCLUSION

There is a significantly increased rate of postoperative embolization for operations begun earlier in the day. Carotid endarterectomies performed in the afternoon may be at less risk of developing postoperative thrombotic stroke.

Carotid angiography in contemporary vascular surgery practice

While most patients with carotid artery disease can safely undergo carotid endarterectomy based on duplex ultrasound alone, carotid angioplasty and stenting must, by its nature, be performed in conjunction with carotid arteriography. The techniques of carotid angiography are a necessary prerequisite to carotid intervention. The indications, technique, and results of carotid angiography in a contemporary vascular surgery practice are described.

Can Carotid Angiography Be Performed by Vascular Surgeons? A Critical Evaluation of Indications, Technique, and Results

The purpose of this report is to examine the contemporary indications for diagnostic carotid arteriography and evaluate its utility and safety when performed by vascular surgeons. The records of all patients having selective carotid arteriography from September 2000 through March 2002 at our institution were reviewed. One hundred sixty-four consecutive patients had selective arteriography of the extracranial carotid arteries for the following indications: hemispheric symptoms with stenosis <80% by duplex ultrasound (20.6%), suspected brachiocephalic trunk stenosis (15.8%), unclear anatomy by duplex (10.3%), recurrent carotid stenosis (10.3%), symptomatic high-grade (>80% by duplex) internal carotid stenosis (9.8%), ipsilateral internal carotid artery occlusion (7.1%), bilateral high-grade internal carotid artery stenoses (7.1%), vertebral-basilar ischemia (7.0%), contralateral internal carotid occlusion (5.4%), duplex ultrasound from a nonaccredited vascular laboratory (3.3%), and evaluation of nonatherosclerotic carotid disease (3.3%). There were no transient ischemic attacks, strokes, or deaths related to the index procedure. Selective angiography of the extracranial carotid arteries remains an important adjunct in the evaluation of patients with carotid disease. This procedure can be performed safely by vascular surgeons.

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.

A Comparison of Magnetic Resonance Angiography, Contrast Arteriography, and Duplex Arteriography for Patients Undergoing Lower Extremity Revascularization

The objective of this study was to compare magnetic resonance angiography (MRA), contrast arteriography (CA), and duplex arteriography (DA) for defining anatomic features relevant to performing lower extremity revascularizations. From March 1, 2001 to August 1, 2001, 33 consecutive inpatients with chronic lower extremity ischemia underwent CA, MRA, and DA before undergoing lower extremity revascularization procedures. The reports of these tests were compared prospectively and the differences in the aortoiliac segment, femoral-popliteal, and infrapopliteal segments were noted. The vessels were classified as mild disease (<50%), moderate disease (50-70%), severe disease (71-99%), and occluded. These studies and treatment plans based on these data were compared. During this time period, 11 patients were not able to undergo MRA and therefore were excluded from the study. Thirty-three patients were included in this study. These patients underwent 35 procedures, as 2 patients underwent bilateral procedures. The mean age of the 33 patients was 76+/-10 years (SD). Indications for the procedures included gangrene (20), ischemic ulcer (8), rest pain (4), and severe claudication (1). Patients' medical history included diabetes mellitus (25), hypertension (20), and end-stage renal disease (5). No differences were noted between intraoperative findings and CA in this series. Two of the three differences between DA and CA were felt to be clinically significant whereas 9 of the 12 differences between MRA and CA were felt to be clinically significant. On the basis of these data in this series, MRA does not yet seem to be able to obtain adequate data on infrapopliteal segments, at least not for this highly selected population. When severe tibial calcification or very low flow states are identified, CA may be necessary for patients undergoing DA.

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.

Carotid Endarterectomy Based on Duplex Ultrasound in Patients with and without Hemispheric Symptoms

Carotid endarterectomy is the most commonly performed vascular procedure. This retrospective study was conducted to determine the efficacy of duplex imaging as the sole diagnostic study for preoperative evaluation of symptomatic and asymptomatic patients who underwent carotid endarterectomy. We conducted a retrospective case series analysis in a community teaching hospital. From January 1994 to September 1998, 316 patients underwent carotid endarterectomy for carotid stenosis. A total of 177 patients were symptomatic and 139 patients were asymptomatic. Angiography was performed routinely in the beginning of the study but later was performed only in selected patients. Preoperative duplex ultrasound of carotid artery was performed by a laboratory accredited by the Intersocietal Commission for the Accreditation of Vascular Laboratories. Data were reviewed to obtain morbidity and mortality rates, and duplex imaging results were compared with operative findings. Cost and risk analysis of carotid angiography reviewed. This study reviewed variables of age, sex, race, diabetes, smoking, hypertension, hypercholesterolemia, coronary artery disease, and renal failure. Five patients had a lesion in the proximal portion of the carotid artery by duplex imaging criteria. Duplex ultrasound results were grossly confirmed intraoperatively in all patients except in one patient who was found to have complete occlusion of carotid artery whose duplex was read as high-grade stenosis. The duration of stay ranged from two to 30 days. This duration was influenced by patients’ comorbid conditions, postoperative complications or simultaneous coronary artery bypass graft. Four patients had a stroke within 30 days of surgery making the stroke rate of 1.26 per cent. There has been considerable debate on the use of duplex ultrasound as the only method of preoperative evaluation of carotid stenosis before carotid endarterectomy. Our study demonstrates that it is safe to perform carotid endarterectomy based on neurologic history and duplex ultrasound with good technical quality performed in an accredited vascular laboratory. This approach eliminates the cost and risk associated with angiography. Proximal carotid and intrathoracic lesions are rare and can be predicted by the duplex study. We think that carotid angiography is required only when duplex imaging is suboptimal or equivocal in the presence of atypical symptoms or uncommon vascular abnormalities.

Reducing the risk of carotid surgery: a 7-year audit of the role of monitoring and quality control assessment

BACKGROUND AND PURPOSE

The current risk of stroke after carotid endarterectomy may be worse than reported in the international trials. Because studies have suggested that most operative strokes follow surgeon error, the aim of the current study was to audit the impact of introducing a strategy of perioperative monitoring and quality control assessment on outcome.

METHODS

A total of 500 patients underwent carotid endarterectomy with intraoperative transcranial Doppler scan monitoring, completion angioscopy, and 3 hours of postoperative transcranial Doppler scan monitoring. The last of these guided selective dextran therapy in patients with high rates of postoperative embolization, which in previous series has been shown to be highly predictive of progression to thromboembolic stroke.

RESULTS

Intimal flaps were repaired in 3% of patients and luminal thrombus removed in 4% of patients. The rate of intraoperative stroke was 0.2%. A total of 313 patients had more than one embolus detected postoperatively (96% within 2 hours of flow restoration), but only 22 patients had sustained embolization requiring dextran. Embolization ceased in all but one patient receiving dextran, although the dose had to be increased in seven patients (36%). One patient was unable to receive adequate dextran therapy because of severe cardiac failure. Overall, the 30-day death/stroke rate was 2.2%, no patient had a perioperative stroke because of carotid thrombosis, and the rate of ipsilateral embolic stroke was 0.8%. Most complications resulted from cardiac pathology or intracranial hemorrhage.

CONCLUSIONS

A program of monitoring and quality control assessment has been associated with a 60% decrease in the operative risk in comparison with that observed before implementation of the protocol.

Are we still performing inappropriate carotid endarterectomy?

OBJECTIVES

the 1998 ECST final report suggests that the decision to operate on patients with greater than 70% symptomatic stenosis should be based on a statistical model incorporating age, sex and degree of stenosis. The aim of this study was to identify patients operated on the basis of the 1991 reports who would not now be offered surgery according to the 1998 ECST recommendations and to determine the surgical morbidity and mortality arising from these <<<<inappropriate>>>> CEAs.

METHODS

interrogation of a prospectively gathered database of all CEAs performed for symptomatic stenosis between 1st January 1994 and 1st May 1998. CEAs were classified as <<<<beneficial>>>>, <<<<uncertain>>>> or <<<<hazardous>>>> according to the 1998 ECST recommendations.

RESULTS

there were 154 males and 72 females (median age (range) was 67 (39-85) and 65 (38-81), respectively). In males 101 (66%) of CEAs were <<<<beneficial>>>>, 51 (33%) were <<<<uncertain>>>> and only two (1%) were <<<<hazardous>>>>. In women, the corresponding proportions were 13 (18%), 45 (63%) and 14 (19%), respectively. The combined peri-operative major stroke (Rankin 3-5) and death rate was 1.8% (4 patients). Of these, three, one and zero patients were in the <<<<beneficial>>>>, <<<<uncertain>>>> and <<<<hazardous>>>> groups.

CONCLUSIONS

strict adherence to the 1998 ECST recommendations would reduce by 50% the number of CEAs currently performed in this vascular unit and, in general, would restrict CEA to a higher risk group. The validity of the ECST model requires further evaluation.

Estimating the contemporary in-hospital costs of carotid endarterectomy

Carotid endarterectomy (CEA) is the treatment of choice for symptomatic carotid stenosis and selective asymptomatic lesions. Alternative approaches have recently been championed under the guise of increased efficacy and decreased cost. The purpose of this study was to determine the results and in-hospital costs of CEA in a university hospital in the modern era. A retrospective chart review was undertaken for all patients undergoing CEA between January 1995 and December 1997. This corresponded to the implementation of a clinical path and extended efforts toward cost reduction. Patients undergoing combined CEA and cardiopulmonary bypass were excluded (n = 3). Cost was analyzed by the hospital Office of Program Planning using TSI (Transition Systems, Inc.) software. Direct costs are related to the utilization of clinical resources and are therefore manageable by clinicians (bed, room, supplies, nursing staff, OR staff, radiology, pharmacy, etc.). Total costs additionally include administration and overhead costs not directly chargeable to patient accounts. The results of this study showed that CEA can be safely performed with brief hospital stays and reasonable hospital costs. Results of alternative interventions for the treatment of carotid stenosis should be compared to these contemporary data.

Carotid duplex imaging: variation and validation

BACKGROUND

Duplex imaging is increasingly used as the only investigation before carotid endarterectomy, but many different criteria exist in the literature for the detection of a severe (70-99 per cent) carotid stenosis. This study aimed to investigate current practice in carotid duplex imaging in Great Britain and Ireland.

METHODS

A postal questionnaire was sent to 86 vascular surgical units.

RESULTS

The median number of scans performed per year was 450 (range 60-4500). Thirty-six per cent of units who responded used peak systolic : end diastolic velocity ratio to calculate carotid stenosis. Overall, nine different major duplex criteria were used to grade carotid stenosis in 14 different systems of percentage bands. Only 51 per cent of units verified their duplex criteria against angiography. Eighteen per cent of units used two or more different types of duplex scanner and applied the same diagnostic criteria to each machine.

CONCLUSION

A wide variation in diagnostic duplex criteria and methods of grading stenosis exists among vascular units. Internal validation is not performed routinely. Standardization of duplex criteria would ensure greater consistency, but would not replace the need for validation of results within each unit.