Preoperative testing before carotid endarterectomy: a survey of vascular surgeons' attitudes

Current Management of Extracranial Carotid Artery Disease

Stroke is the third most common cause of death in the United States. There are approximately 700,000 strokes/year; 80% are ischemic, and 20-30% of ischemic strokes are secondary to carotid disease. Carotid stenosis is traditionally treated by carotid endarterectomy (CEA). Multicenter, randomized, controlled trials have shown that surgery significantly reduces the risk of ipsilateral stroke in patients with severe symptomatic and asymptomatic carotid stenosis. Endovascular techniques for treating carotid stenosis have been developed over recent years. Carotid angioplasty and stenting (CAS) with cerebral protection has become an alternative to CEA for high-surgical-risk patients and the procedure of choice for stenoses inaccessible by surgery. In this review we summarize the existing data regarding the traditional state of management of extracranial carotid artery stenosis and compare these data to a critical analysis of the recent results of CAS.

EFNS guideline on neuroimaging in acute stroke. Report of an EFNS task force

Neuroimaging techniques are necessary for the evaluation of stroke, one of the leading causes of death and neurological impairment in developed countries. The multiplicity of techniques available has increased the complexity of decision making for physicians. We performed a comprehensive review of the literature in English for the period 1965-2005 and critically assessed the relevant publications. The members of the panel reviewed and corrected an initial draft, until a consensus was reached on recommendations stratified according to the European Federation of Neurological Societies (EFNS) criteria. Non-contrast computed tomography (CT) scan is the established imaging procedure for the initial evaluation of stroke patients. However, magnetic resonance imaging (MRI) has a higher sensitivity than CT for the demonstration of infarcted or ischemic areas and depicts well acute and chronic intracerebral hemorrhage. Perfusion and diffusion MRI together with MR angiography (MRA) are very helpful for the acute evaluation of patients with ischemic stroke. MRI and MRA are the recommended techniques for screening cerebral aneurysms and for the diagnosis of cerebral venous thrombosis and arterial dissection. For the non-invasive study of extracranial vessels, MRA is less portable and more expensive than ultrasonography but it has higher sensitivity and specificity for carotid stenosis. Transcranial Doppler is very useful for monitoring arterial reperfusion after thrombolysis, for the diagnosis of intracranial stenosis and of right-to-left shunts, and for monitoring vasospasm after subarachnoid hemorrhage. Currently, single photon emission computed tomography and positron emission tomography have a more limited role in the evaluation of the acute stroke patient.

Initial Experience with Routine Selective Carotid Arteriography by Vascular Surgeons

We report the results of our first 2 years of experience with routine carotid angiography with an emphasis on technique and complications. We reviewed the hospital records, office charts, and prospective quality-assurance database records of 336 patients undergoing cerebrovascular arteriograms and collected data on the indications, complications, and technical aspects of the procedures. Indications for angiography included carotid stenosis in 331 (95%) patients, subclavian steal syndrome in 9 patients, vertebrobasilar insufficiency in 6 patients, and carotid body tumor in 2 patients. Selective catheterizations were performed on 654 common carotid arteries, 63 subclavian arteries, and 63 vertebral arteries. Both common carotid arteries were not selectively catheterized in 34 (9.8%) patients. Reasons for not selecting one or both common carotid arteries included physician choice to limit contrast administration in patients with renal insufficiency in 16 cases, proximal occlusion in 4 cases, proximal stenosis thought to be at risk of embolization if instrumented in 3 cases, imaging equipment malfunction in 2 cases, and in only 9 (2.6%) cases was selective carotid catheterization attempted but unsuccessful. There were no procedure-related deaths. Complications were documented in six (1.8%) patients, including cerebrovascular accident (CVA) in 1 (0.3%) patient. One hundred forty-two (41%) patients went on to carotid endarterectomy, and we performed 16 carotid bifurcation stents during the study period. Routine selective carotid angiography is a low-risk procedure that can be performed safely by vascular surgeons with catheter/guide wire skills.

Effect of Nonoptimal Imaging on the Relationship Between the Measured Degree of Symptomatic Carotid Stenosis and Risk of Ischemic Stroke

BACKGROUND AND PURPOSE

Some recent studies of noninvasive carotid imaging have identified high rates of inappropriate decision-making about endarterectomy compared with conventional arterial angiography (CAA), but there is substantial inconsistency across the published literature. CAA is usually regarded as the gold standard for carotid imaging, partly because the degree of angiographic stenosis is a powerful predictor of ischemic stroke and hence of benefit from endarterectomy. However, there are very few published data on the extent to which predictive power varies with type of CAA or the number and quality of views of the stenosis obtained.

METHODS

We analyzed measurements of stenosis made by 2 independent observers on 967 consecutive patients randomized to medial treatment alone in the European Carotid Surgery Trial (ECST). We determined prediction of 3-year risk of ipsilateral ischemic stroke (as a hazard ratio from a Cox model and as the area under a receiver operating characteristic curve [AUC]) in relation to the technique of angiography, the number and quality of views of the stenosis, and the use of 2 independent measurements.

RESULTS

Using 2 independent measurements of stenosis increased predictive power slightly, but the effect was much smaller than that attributable to the type of CAA and the number of views of the stenosis. Prognostic value was greater in patients who had selective carotid injection CAA and at least biplane views (AUC, 0.75; 0.68 to 0.82) than in patients with only a single view or aortic arch injection CAA (AUC, 0.65; 0.56 to 0.73; P=0.03).

CONCLUSIONS

The dependence of the prognostic value of CAA on the type of angiography and the number of views of the stenosis obtained has implications for the future development and validation of noninvasive methods of carotid imaging.

Cost-effectiveness of diagnostic strategies prior to carotid endarterectomy

The main objective of this study was to assess the long-term cost-effectiveness of five alternative diagnostic strategies for identification of severe carotid stenosis in recently symptomatic patients. A decision-analytical model with Markov transition states was constructed. Data sources included a prospective study involving 167 patients who had screening Doppler ultrasound (DUS), confirmatory contrast-enhanced magnetic resonance angiography (CEMRA) and confirmatory digital subtraction angiography (DSA), individual patient data from the European Carotid Surgery Trial and other published clinical and cost data. A "selective" strategy, whereby all patients receive DUS and CEMRA (only proceeding to DSA if the CEMRA is positive and the DUS is negative), was most cost-effective. This was both the cheapest imaging and treatment strategy (35,205 dollars per patient) and yielded 6.1590 quality-adjusted life years (QALYs), higher than three alternative imaging strategies. Probabilistic sensitivity analysis demonstrated that there was less than a 10% probability that imaging with either DUS or DSA alone are cost-effective at the conventional 50,000 dollars/QALY threshold. In conclusion, DSA is not cost-effective in the routine diagnostic workup of most patients. DUS, with additional imaging in the form of CEMRA, is recommended, with a strategy of "CEMRA and selective DUS review" being shown to be the optimal imaging strategy.

Safety and efficacy of carotid arteriography in vascular surgery practice

OBJECTIVE

Carotid arteriography (CA) is an important method of assessing carotid artery occlusive disease and is the best method of planning for carotid angioplasty and stent placement (CAS). This study compared the results of CA performed by vascular surgeons in a contemporary series against widely recognized interdisciplinary quality standards for this procedure. Although many vascular surgeons perform CA, there is a paucity of data about its safety, efficacy, and compliance with quality standards in vascular practice. The importance of quality CA will likely increase as CAS emerges to assume a broader clinical role.

METHOD

Carotid arteriograms performed by seven vascular surgeons at three institutions from September 2000 to May 2004 were reviewed. These results were compared with quality standards for the performance of CA.

RESULTS

Five hundred three carotid arteriograms were performed over 45 months. Indications for the procedure were extracranial cerebrovascular disease (86%), trauma (5%), and other conditions (9%). Indications for the procedure were appropriate in 100% of patients (as determined by guidelines document) and exceeded the recommended standard of appropriate indications in 99%. All procedures successfully provided the information required, exceeding the threshold of 98% for procedural success. Reversible neurologic deficits occurred in 0.6% (two transient ischemic attacks and one stroke) compared with the threshold of 2.5%. A permanent neurologic deficit occurred in 0.2% (1 patient) compared with the published guideline of 1% after carotid arteriography. Major non-neurologic complications occurred in 1.2% (6 patients), less than the standard of 2.0%.

CONCLUSIONS

The safety and efficacy of a contemporary series of CA performed in vascular surgery practice compared favorably with recognized interdisciplinary quality standards for this procedure. Ensuring safe and effective CA is likely to support the successful growth of CAS as a treatment option.

Conventional digital subtraction x-ray angiography versus magnetic resonance angiography in the evaluation of carotid disease: patient satisfaction and preferences

AIM

To compare conventional digital subtraction x-ray angiography (DSA) and contrast-enhanced magnetic resonance angiography (MRA) of the carotid arteries in terms of patient satisfaction and preferences.

METHODS

One hundred and sixty-seven patients with symptomatic carotid artery disease, who underwent both DSA and MRA, were prospectively recruited in this study. Patients' perceptions of each method were assessed by the use of a questionnaire after each procedure. Main outcome measures were anxiety, pain, satisfaction rate and patient preferences.

RESULTS

DSA generated more anxiety and pain during the procedure, but the severity of these ill-effects was mild. Satisfaction rates for each method were similar. More patients were, however, willing to have a repeat MRA compared with DSA (67 versus 41%). The majority of patients (62%) preferred MRA over DSA (31%). The shorter MRA imaging time was found to be a significant factor in patients' acceptance of the technique. The main reasons cited by patients for their dislike of a particular procedure was noise and claustrophobia for MRA and invasiveness, pain and post-procedural bed rest for DSA.

CONCLUSIONS

MRA is the method that is preferred by the majority of patients, although the actual disutility of DSA may be small. Assuming equal diagnostic accuracy, our data supports replacement of DSA by MRA for routine carotid imaging.

EFFECT OF CAROTID BIFURCATION LOCATION ON THE LENGTH OF INTERNAL CAROTID DISEASE

BACKGROUND

A relationship between the height of the carotid bifurcation and the extent of disease in the internal carotid artery has not been reported. The aim of the present study was to determine if such a correlation exists.

METHODS

Fifty-one patients undergoing carotid endarterectomy had measurements made of the height of the carotid bifurcation from the sternoclavicular joint. The length of disease removed distal to the bifurcation after carotid endarterectomy was also measured. Correlation analysis was performed.

RESULTS

There is a statistically significant negative correlation between the extent of disease in the internal carotid artery and the height of the bifurcation.

CONCLUSIONS

A low carotid bifurcation correlates with a longer extent of disease in the internal carotid artery.

The diagnostic accuracy of computed tomography angiography for traumatic or atherosclerotic lesions of the carotid and vertebral arteries: a systematic review

INTRODUCTION

Helical computed tomography angiography (CTA) has become an established technique for evaluating atherosclerosis of the cerebrovascular arteries. However, the role of CTA in penetrating and blunt trauma to the carotid and vertebral arteries is not well defined. We conducted a systematic literature review to determine the diagnostic accuracy of CTA for atherosclerotic, penetrating and blunt lesions in the carotid and vertebral arteries.

METHODS

We searched MEDLINE and EMBASE databases to identify studies evaluating the diagnostic accuracy of CTA of the carotid and vertebral arteries published between January 1, 1992 and December 31, 2002. Two reviewers independently assessed abstracts and full text to determine study eligibility. Information on methodological quality, imaging technique and diagnostic accuracy was abstracted from all eligible studies by three independent reviewers. We pooled sensitivity and specificity data from diagnostic accuracy studies of high methodological quality.

RESULTS

Forty-three articles met the inclusion criteria and were included in the review. Thirty studies examined atherosclerotic disease, two blunt trauma, two penetrating trauma and nine examined patients with other pathology. Pooled data from 15 higher quality studies demonstrated that CTA had a sensitivity of 95% (91-97% CI) for detecting severe (>70%) atherosclerotic stenosis of the carotid artery. The specificity of CTA for severe stenosis was also high 98% (96-99% CI). CTA remained a sensitive technique (95%; 93-97% CI) when the criterion for a positive result is relaxed to moderate or greater (>30%) stenosis. Two studies raised concerns about the use of CTA in the blunt trauma setting, suggesting that CTA may not be sensitive for detecting small intimal injuries, although both of these studies used older technologies for either obtaining or viewing images. Conversely, two penetrating trauma studies concluded that the sensitivity of CTA was high.

CONCLUSIONS

Our findings demonstrate that CTA is both a sensitive and specific imaging technique for identifying severe atherosclerotic stenosis and occlusion of the carotid arteries. However, there is currently not enough high quality evidence to accurately estimate the sensitivity and specificity of CTA in the setting of blunt or penetrating trauma.

Contrast-enhanced magnetic resonance angiography of carotid arteries: utility in routine clinical practice

BACKGROUND AND PURPOSE

Contrast-enhanced magnetic resonance angiography (CEMRA) is among the newer noninvasive tests used for the evaluation of patients with carotid artery disease. Evidence supporting its utility in routine clinical practice is lacking.

METHODS

The results of CEMRA were compared with those of catheter angiography in 50 consecutive patients being evaluated for carotid endarterectomy (CEA) at a community hospital. Using indications for CEA based on published guidelines, we determined the rate of misclassification for surgery, sensitivity, specificity, and positive and negative predictive values. In addition, the interrater agreement (kappa score) of CEMRA was compared with that of catheter angiography in the studied population and with interpretations provided by 2 blinded radiologists.

RESULTS

Compared with catheter angiography, 24% (95% CI, 12% to 36%) of patients would have been misclassified for CEA on the basis of CEMRA results alone. CEMRA was associated with sensitivity of 92%, specificity of 62%, positive predictive value of 78%, and negative predictive value of 89%. When both CEMRA and duplex Doppler ultrasound were performed and the results were concordant, the misclassification rate decreased to 17% (95% CI, 2% to 32%). kappa scores were similar for CEMRA and catheter angiography (0.72 and 0.75, respectively).

CONCLUSIONS

CEMRA was found to be highly sensitive for detection of surgically amenable carotid stenosis. kappa scores for the interpretation of CEMRA and catheter angiography were similar. However, clinicians should be cautious when using CEMRA alone for surgical decision making in CEA candidates because a significant number of patients may be misclassified. The rate of misclassification is reduced when the results of CEMRA and duplex Doppler ultrasound are concordant.

Routine duplex surveillance does not improve the outcome after carotid endarterectomy: a decision and cost utility analysis

BACKGROUND

Doppler ultrasound (duplex) tests are commonly applied after carotid endarterectomy to detect possible recurrent stenosis. The appropriate frequency and the benefits are unknown. We investigated the costs and effects of various follow-up strategies to determine the optimal strategy after carotid endarterectomy.

METHODS

Using decision-analytic methods, a Monte Carlo Markov model was constructed. Probabilities and costs were obtained by systematic literature review. From empirical data regarding restenosis, a disease model was constructed to test the effect of various follow-up strategies using duplex testing and angiography. Main outcome measures were quality-adjusted life-years (QALYs), probability of stroke, and costs (for both the Dutch and the American situation).

RESULTS

The average quality-adjusted life expectancy for a 66-year-old patient was 6.31 years for the symptom-guided strategy (with duplex scanning only being performed in case of symptoms of cerebral ischemia). The mean lifetime costs for this strategy were $5 600 for the US and 4 600 Euro for the Netherlands. The cumulative probability of stroke was 13%. Yearly routine duplex tests up to 5 years after operation resulted in similar QALYs and a similar probability of stroke, but higher costs ($7 300 for the US and 5 600 Euro for The Netherlands situation). No other strategy, including routine duplex surveillance, increased QALYs. When MR instead of conventional angiography was used as confirmatory test, no improvement was observed either.

CONCLUSIONS

Routine duplex surveillance does not result in an increase in quality-adjusted life expectancy, but it does increase costs. After successful carotid endarterectomy, a symptom-guided follow-up is an appropriate approach.

Utility of noninvasive studies in the evaluation of patients with carotid artery disease

Endarterectomy reduces the risk of stroke in selected patients with carotid artery stenosis, and the benefit is related to the degree of stenosis. Although the randomized trials demonstrating this benefit measured the degree of stenosis with conventional catheter angiography, many physicians are relying on noninvasive tests to select patients for surgery. Technologic advancement in this area is outpacing the availability of quality data supporting the clinical utility of the newer noninvasive tests.

Results of carotid endarterectomy performed with preoperative duplex ultrasound assessment alone

Contrast injection cerebral angiography has been considered for several decades the "gold-standard" technique for diagnosis and operative planning of carotid disease. More recently, however, an increasing number of institutions are using duplex ultrasound as the single independent preoperative test. The objective of this investigation was to evaluate the impact of the utilization of duplex ultrasonography as the only preoperative test on the outcome of the procedure. Between 1993 and 1996, the authors performed 1,149 carotid procedures. Duplex ultrasound as the only preoperative test was employed with increasing frequency in a total of 728 cases. In 1995 and 1996, a cerebral arteriogram was performed only if duplex ultrasound was technically inadequate or questionable or showed an atypical pattern of disease. During the 4 years analyzed in this study, the number of the procedures increased from 165 in 1993 to 412 in 1996. The thirty-day mortality rate was 0.43%, and neurologic morbidity was 1.65%. According to the year in which the procedure was performed, the mortality/morbidity rates were 1.2/2.4 in 1993, 0.52/2.08 in 1994, 0.26/1.57 in 1995, and 0.24/1.21 in 1996. Indication to perform an arteriogram became very selective in 1995. Regardless of these changes in the diagnostic work-up, some degree of reduction in both 30-day mortality and neurologic morbidity was recorded. Considering a cost of 724 European Currency Units (ECU) per arteriogram, 527,072 ECU were saved in this period. In the last 4 years, duplex ultrasound has replaced arteriography as the first-choice technique for preoperative assessment of carotid disease at the authors' institution. There was definitely no detrimental effect on the clinical results that, on the contrary, improved during the same period. This policy has allowed a significant reduction in the cost of the procedure and has most likely prevented several arteriography-related complications. The authors recommend this policy to all institutions in which accurate duplex ultrasound is available.

Validity of duplex ultrasound as a diagnostic modality for internal carotid artery disease

There is an increasing trend to rely on duplex ultrasound rather than angiography to measure an internal carotid artery stenosis. The aim of this study was to determine the validity of ultrasound assessment of carotid stenosis performed in community based vascular laboratories. We compared ultrasound with angiography in 225 patients referred to us for carotid intervention. Mild lesions were diagnosed by ultrasound with a sensitivity of 54%, specificity of 89%, and a positive predictive value of 89% compared with angiography. Severe lesions had a sensitivity of 93%, a specificity of 67%, and a positive predictive value of 45%. Receiver operator characteristic curves demonstrated the optimal ultrasound cut-off value of 66% stenosis as a predictor of >60% stenosis measured angiographically, is associated with a false positive rate of 38%, and a false negative rate of 9%. Similarly, if a cut-off of 76% on ultrasound is used to predict >70% stenosis measured angiographically, it would be associated with a 29% false positive rate and a false negative rate of 11%. Despite the value of non-invasive testing for carotid disease, duplex ultrasonography performed in non-accredited and some accredited laboratories may produce highly variable results. Using ultrasound as the sole diagnostic test to determine the severity of a carotid stenosis may result in a high number of inappropriate operations and a large proportion of patients who may not be offered treatment due to false negative diagnoses.

Angiographic criteria reliably predict when carotid endarterectomy can be safely performed without a shunt

BACKGROUND

Selective shunting during carotid endarterectomy is widely performed, but the optimal approach for predicting when a shunt is unnecessary remains uncertain. We evaluated the ability of preoperative cerebral angiography to predict when carotid endarterectomy could be safely performed without a shunt.

STUDY DESIGN

Eighty-seven patients undergoing carotid endarterectomy between August 1991 and December 1997 had preoperative cerebral angiograms. The angiograms were evaluated for the presence of collateral flow from the contralateral carotid through the anterior communicating artery and from the posterior circulation through the posterior communicating artery. Patients then underwent endarterectomy and were selectively shunted based on somatosensory evoked potential changes. Internal carotid artery stump pressure was routinely measured in all patients.

RESULTS

Nine patients (10%) had a shunt placed based on somatosensory evoked potential changes and none of the 87 patients had a perioperative (30 days) stroke. Angiography revealed that 36 patients (41%) had no cross-filling from the contralateral carotid through the anterior communicating artery. Nine of these patients (25%) required a shunt; none of the 51 patients with adequate cross-filling (p < 0.001) did. Furthermore, 94% of the patients without cross-filling but with a patent ipsilateral posterior communicating artery did not require a shunt using somatosensory evoked potential changes as the standard for shunt insertion. Stump pressure measurements (> or = 25 mmHg) or (> or = 50 mmHg) did not reliably exclude the need for a shunt. Only 2 of 15 patients with contralateral carotid occlusion and 1 of 16 patients with a prior ipsilateral stroke required shunts.

CONCLUSIONS

In the presence of cross-filling from the contralateral carotid artery, shunt insertion was uniformly unnecessary. In addition, routine shunting of patients with previous ipsilateral strokes or contralateral carotid occlusion was not always necessary. Stump pressures were less sensitive than angiographic criteria in determining when a shunt was unnecessary. Evaluation of cross-filling from the contralateral carotid artery on preoperative angiography can predict with certainty which patients will not require a shunt.

Cerebral tomographic findings in patients undergoing carotid endarterectomy for asymptomatic carotid stenosis: short-term and long-term implications

PURPOSE

Preoperative cerebral imaging has been considered not to be cost-effective in carotid endarterectomy (CEA) for asymptomatic carotid stenosis. Yet, silent brain infarction (SBI) has been associated with the embolization potential of a severe carotid stenosis. Thus the presence of SBI may represent an additional indication for CEA in asymptomatic patients. We examined the predictive value of preoperatively detected silent cerebral lesions on early and late outcomes in patients undergoing CEA for asymptomatic carotid stenosis.

METHODS

Preoperative cerebral tomographic (CT) scans performed on 301 asymptomatic patients undergoing 346 CEAs from 1986 to 1995 were reviewed by a single neuroradiologist blinded to patients' records. Mean follow-up was 67. 3 months (range, 24-130 months). The degree of internal carotid lumen reduction was measured bilaterally in all patients (602 carotid arteries); carotid stenosis of 60% or more was found in 399 carotid arteries.

RESULTS

Of the 103 (34%) CT scans positive for cerebral lesions, 58% were lacunar. No significant association was observed between the side of the cerebral lesion on CT scan and the severity of the corresponding carotid stenosis; 38 silent lesions were detected in the 203 hemispheres ipsilateral to carotid stenoses that were less than 60% versus 95 SBIs in the 399 hemispheres ipsilateral to carotid stenoses that were 60% or more (19% vs 24%; P =.2). There were no significant differences in the perioperative stroke/death rate in patients with or without cerebral CT lesions (2% vs 1%; odds ratio, 1.94; P =.6). Mortality rate during follow-up was 22% in patients with preoperative SBI and 15% in patients without SBI (P =.1). However, actuarial survival at 10 years was shorter (P =.02) in patients with SBI. Late stroke occurred in 11% of patients with preoperative SBI and in 3% of patients without preoperative SBI (P =.006). Cox regression analysis showed that both preoperative lacunar and nonlacunar infarctions were independent predictors of late stroke (hazard ratio, 3.6; P =.04; and hazard ratio, 7.1; P =.001; respectively).

CONCLUSION

In our experience, preoperative SBI did not occur more frequently in the hemisphere ipsilateral to asymptomatic severe carotid stenosis. Although our study lacks a medically treated control group, our data show that SBI is predictive of poor neurologic outcome in asymptomatic patients undergoing CEA. We conclude that CT before CEA, selectively applied, provides information on long-term neurologic prognosis and that a less aggressive attitude towards CEA in asymptomatic patients with SBI may be justified.

Decreasing carotid endarterectomy length of stay at a university hospital

In 1995, a clinical pathway for carotid endarterectomy patients was instituted at the authors' institution. The effect of this program on length of stay and patient outcomes was investigated. Records of 152 consecutive carotid endarterectomies performed by a single surgeon over a 45-month period with identical technique (general anesthesia, routine shunting, closure with a dacron patch) were reviewed. Comparison of patients treated under the pathway (n = 119) and those prior to that policy (n = 33) revealed no significant differences (P>0.05) in age, sex, co-morbid conditions, or surgical indication. No difference (P>0.05) was found for occurrence of complications, which included two fatal perioperative strokes (1.3%) and two myocardial infarctions (1.3%) (one fatal). No complications occurred after discharge and no patients required readmission to the hospital. Average length of stay was reduced from 6.0 to 3.3 days, with 78% of patients discharged within 48 h. Preoperative hospitalization decreased from 100 to 21%. A decrease in the use of preoperative arteriography from 100 to 10% was noted. The cost of vascular studies decreased from $2451 to $1228. Cost-saving measures, including early discharge of stable patients, elimination of preoperative hospitalization and decreased use of arteriography, can be accomplished while maintaining acceptable complication rates following carotid endarterectomy in a university hospital setting.

Can duplex scan arterial mapping replace contrast arteriography as the test of choice before infrainguinal revascularization?

PURPOSE

Arteriography is the diagnostic test of choice before lower extremity revascularization, because it is a means of pinpointing stenotic or occluded arteries and defining optimal sites for the origin and termination of bypass grafts. We evaluated whether a duplex ultrasound scan, used as an alternative to arteriography, could be used as a means of accurately predicting the proximal and distal anastomotic sites in patients requiring peripheral bypass grafts and, therefore, replace standard preoperative arteriography.

METHODS

Forty-one patients who required infrainguinal bypass grafts underwent preoperative duplex arterial mapping (DAM). Based on these studies, an observer blinded to the operation performed predicted what operation the patient required and the best site for the proximal and distal anastomoses. These predictions were compared with the actual anastomotic sites chosen by the surgeon.

RESULTS

Whether a femoropopliteal or an infrapopliteal bypass graft was required was predicted correctly by means of DAM in 37 patients (90%). In addition, both anastomotic sites in 18 of 20 patients (90%) who had femoropopliteal bypass grafts and 5 of 21 patients (24%) who had infrapopliteal procedures were correctly predicted by means of DAM.

CONCLUSION

DAM is a reliable means of predicting whether patients will require femoropopliteal or infrapopliteal bypass grafts, and, when a patient requires a femoropopliteal bypass graft, the actual location of both anastomoses can also be accurately predicted. Therefore, DAM appears able to replace conventional preoperative arteriography in most patients found to require femoropopliteal reconstruction. Patients who are predicted by means of DAM to require crural or pedal bypass grafts should still undergo preoperative contrast studies to confirm these results and to more precisely locate the anastomotic sites.

Accuracy of duplex ultrasound in evaluating carotid artery anatomy before endarterectomy

PURPOSE

Anatomic features, such as a high carotid bifurcation (< 1.5 cm from the angle of the mandible), excessive distal extent of plaque (> 2.0 cm above the carotid bifurcation), or a small diameter (< or = 0.5 cm) redundant or kinked internal carotid artery can complicate carotid endarterectomy. In the past, arteriography was the only preoperative study capable of imaging these features. This study assessed the ability of duplex ultrasound to evaluate their presence before surgery.

METHODS

A consecutive series of 20 patients who underwent 21 carotid endarterectomies had preoperative duplex ultrasound evaluations of these anatomic features. These evaluations were correlated with operative measurements from an observer blinded to the duplex findings.

RESULTS

The mean difference between duplex and operative measurements for the distance between the carotid bifurcation and the angle of the mandible, the distal extent of plaque, and the internal carotid artery diameter was 0.9 cm, 0.3 cm, and 0.8 mm, respectively. The correlation coefficient between the two methods was 0.86, 0.75, and 0.59, respectively. Duplex ultrasound predicted a high carotid bifurcation, excessive distal extent of plaque, or a redundant or kinked internal carotid artery with 100% sensitivity (p < 0.05, p < 0.01, and p < 0.001, respectively). The sensitivity of duplex ultrasound in predicting a small internal carotid artery diameter was 80%. The specificity of duplex ultrasound for predicting excessive distal extent of plaque, small internal carotid artery diameter, high carotid bifurcation, and a coiled or kinked carotid artery was 92%, 56%, 100%, and 100%, respectively.

CONCLUSION

Duplex ultrasound can predict the presence of anatomic features that may complicate carotid endarterectomy. Preoperative duplex imaging of these features may be helpful in patients who undergo carotid endarterectomy without preoperative arteriography.