Carotid surgery without angiography

Extracranial and Transcranial Color-Coded Sonography Reduce the Need for Angiography Prior to Carotid Endarterectomy

The growing need for carotid endarterectomy must be accompanied by safe and reliable methods of imaging the cerebral circulation. The authors used extracranial and tran scranial color-coded sonography to evaluate the cervical carotid arteries and the basal cerebral circulation in 76 patients prior to surgery, aiming to reduce the need for preop erative angiography. In 3 patients (proximal and distal carotid disease; subtotal occlusion) carotid ultrasound failed to define the nature and extent of stenosis adequately, and thus conventional angiography was performed. Transcranial imaging identified intracranial stenotic disease in 4 patients and interhemispheric collateral flow in 29 patients. All patients underwent carotid endarterectomy without any complications due to inadequate preoperative imaging. An ultrasound-based approach eliminated the need for angiography in the majority of patients with significant implications for risk reduction and financial expenditure.

Detection of Carotid Artery Disease by Duplex Ultrasound

Carotid duplex ultrasonography is a common noninvasive technique for evaluating cases of suspected extracranial carotid artery occlusive disease. This manuscript describes the procedure, with an emphasis on positive findings. A review of 16 published studies, totaling 2,168 arteriogram correlations, demonstrates a sensitivity, specificity, and overall accuracy of 95%, 73%, and 91%, respectively, for the detection of stenosis. The ability of the technique to predict the presence of plaque ulceration and intraplaque hemorrhage is less well defined. Carotid duplex ultrasonography is a highly accurate technique for the detection of extracranial carotid artery occlusive disease.

Poor agreement in carotid artery stenosis detection by ultrasound between external offices and a vascular center

BACKGROUND

Carotid duplex ultrasonography is the prime investigation used to grade carotid artery stenosis in clinical routine. We compared the carotid ultrasound (US) scans performed externally with our results.

MATERIALS AND METHODS

This retrospective study included 288 patients who had been referred to our outpatient department and initially presented with an external carotid duplex scan report indicating carotid atherosclerosis. The external scans were analyzed and compared with our scans in respect of the accuracy of identification and quantification of stenosis, the criteria used to grade stenosis and the duplex criteria used. Weighted Kappa coefficients (K) were computed to quantify the agreement between internal and external findings.

RESULTS

The majority of the external reports had been performed by radiologists [70.8 % (n = 204)], followed by specialists of internal medicine [19.4 (n = 56)] and by neurologists [9.8 % (n = 28)]. Only slight agreement was registered between the external reports and those performed at our institution with regard to the identification of stenosis (K = 0.2 for the left and K = 0.12 for the right side). Greater agreement was observed in respect of the level of stenosis (K = 0.42 for the right and K = 0.54 for the left side). Overestimation of the level of stenosis was registered for 45 % in the left internal carotid artery (ICA) and 36 % in the right ICA; the overestimation was most pronounced for occlusions and high-grade stenoses, which is a source of great concern for decision-making.

CONCLUSIONS

The present data indicate only a slight agreement between carotid duplex US imaging performed at medical offices and our results.

Experiences of duplex ultrasonography of carotid arteries performed by clinicians--correlation to angiography

One hundred and eleven carotid vessels in 56 patients were analysed by high-resolution duplex ultrasound. Vessels were graded as normal, 25, 50 or 75% stenotic and 100% occluded and the results were compared with similarly graded biplanar angiograms. There was absolute agreement in 68.5% of the vessels, agreement within one grade of severity of disease in 27.0%, while poor correlation was obtained in 4.5%. The results of ultrasound and angiography were also related to the surgical specimens obtained after thrombendarterectomy of 23 vessels in 20 patients. Good agreement was obtained between the three methods in 20/23 vessels. In one case ultrasound was better than angiography, in another case the reverse was true and in a third case both methods overdiagnosed a plaque. It is concluded that duplex ultrasound will work in the hands of a clinician and is a reliable non-invasive screening method for carotid artery disease leading to a more optimal selection of candidates for angiography.

Contrast-Enhanced 3-D MRA in Decision Making for Carotid Endarterectomy: A 6-Year Experience

BACKGROUND

Systematic need for angiography in diagnosis of carotid artery stenosis and indication of surgical therapy is still debated. Noninvasive imaging techniques such as MR angiography (MRA) or CT angiography (CTA) offer an alternative to digital subtraction angiography (DSA) and are increasingly used in clinical practice. In this study, we present the radiological characteristics and clinical results of a series of patients operated on the basis of combined ultrasonography (US)/MRA.

METHODS

This observational study included all the patients consecutively operated for a carotid stenosis in our Department from October 1998 to December 2004. The applied MRA protocol had previously been established in a large correlation study with DSA. DSA was used only in case of discordance between US and MRA. The preoperative radiological information furnished by MRA was compared with intraoperative findings. The outcome of the operation was assessed according to ECST criteria.

RESULTS

Among 327 patients, preoperative MRA was performed in 278 (85%), DSA in 44 (13.5%) and CT angiography in 5 (1.5%). Most of DSA studies were performed as emergency for preparation of endovascular therapy or for reasons other than carotid stenosis. Eleven additional DSA (3.3%) complemented US/MRA, mostly because diverging diagnosis of subocclusion of ICA. No direct morbidity or intraoperative difficulty was related to preoperative MRA. Combined mortality/major morbidity rate was 0.9% (3 patients) and minor morbidity rate 5.5% (18 patients).

CONCLUSIONS

This observational study describes a well-established practice of carotid surgery and supports the exclusive use of non invasive diagnostic imaging for indicating and deciding the operation.

Reliability of common femoral artery hemodynamics in assessing the severity of aortoiliac inflow disease

OBJECTIVES

We investigated the utility of color duplex ultrasound (CDU)-derived common femoral artery (CFA) hemodynamics for detecting significant aortoiliac occlusive disease and predicting its severity.

METHODS

From January 1997 to June 2001, 132 consecutive patients with lower extremity arterial insufficiency underwent both femoropopliteal CDU scanning and aortography with runoff studies. CDU-derived CFA waveform contour (monophasic, biphasic, or triphasic), peak systolic velocity (PSV), and acceleration time were recorded for each patient. Severity of aortoiliac occlusive disease was classified by arteriography into three distinct groups: normal or minimal disease (<50%, group 1), significant focal or diffuse stenoses (>/=50%, group 2), or total occlusion (group 3). Using probability and receiver operating characteristic curve analysis, waveform contour and PSV were compared alone and in combination with the arteriographic groups to identify waveform contours and threshold PSV, which may accurately differentiate the three categories of aortoiliac occlusive disease.

RESULTS

Of 214 limbs available for study, 112 composed group 1, 70 composed group 2, and 32 composed group 3. Concomitant femoropopliteal disease was present in 47% of limbs in group 1, 53% of limbs in group 2, and 34% of limbs in group III. An abnormal CFA waveform contour (monophasic or biphasic) differentiated group 1 from groups 2 and 3, with 95% sensitivity, 89% specificity, 89% positive predictive value (PPV), 95% negative predictive value (NPV), and 92% accuracy. Mean PSV and acceleration time for monophasic and biphasic waveforms were 39 cm/sec +/- 19, 178 msec +/- 36 vs 95 cm/sec +/- 67, 97 msec +/- 31 respectively (P <.05). In differentiating between groups 2 and 3, the specificity, PPV, and accuracy for CFA PSV of </=45 cm/sec alone and for the PSV </=45 cm/sec combined with a CFA monophasic waveform were 89%, 76%, 85% and 97%, 92%, 88%, respectively. Concomitant significant superior femoral artery and bilateral iliac disease did not influence these findings.

CONCLUSION

CFA PSV 45 cm/s or less combined with a monophasic waveform is highly predictive of ipsilateral iliac occlusion. These results were independent of contralateral iliac and distal superior femoral artery disease. CFA color duplex US scanning may be considered an alternative technique to direct duplex scanning of the aortoiliac segment in patients being evaluated for inflow endoluminal or bypass procedures.

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.

Changing characteristics of carotid endarterectomy

We have noted significant differences in terms of our preoperative work-up, length of stay, morbidity, and mortality of patients undergoing carotid endarterectomy (CEA) from findings reported in large published randomized clinical trials. To further investigate these differences, we have reviewed our recent experience. CEA has proved to be the most effective approach to avert stokes caused by significant atherosclerotic disease of the carotid bifurcation. Between January 1, 1996 and December 31, 1998, 552 patients underwent CEA at our institution. Forty percent were performed in symptomatic patients with stenotic lesions > 60% in diameter by duplex ultrasonography. The remainder were performed for asymptomatic lesions > 60% in diameter. No patient underwent contrast angiography. Fifty-two percent of the patients were males. The mean age was 74 +/- 8 years old. General anesthesia was used in 97% of the cases and regional block, in 3%. All patients underwent routine postoperative measurement of serum creatinine phosphokinase (CPK) isoenzymes. Patients were discharged when deemed clinically stable. The patients' follow-up visits at 1 week and at 3-5 months after the procedure (mean, 3.4 months) included a neurological exam and duplex exam. Patient results suggest that CEAs can be performed in the modern era without contrast arteriography. Most patients can be discharged on the first postoperative day. In addition, previously acceptable rates of postoperative morbidity and mortality should perhaps be revised to meet current standards. Contrary to the previous concept that most postoperative strokes are due to embolic phenomena, hyperperfusion syndrome played an increasingly important role in this review.

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.

Vascular surgery without arteriography: use of Duplex ultrasound

Although contrast arteriography has served as the historical 'gold standard' for diagnosis of arterial disease, recent improvements in noninvasive diagnostic methods have made it possible to plan surgical treatment without subjecting patients to this invasive procedure. This approach avoids both the risks and costs associated with arteriography. Duplex scanning has become the standard noninvasive test for extracranial carotid artery disease, and it can also be used to directly evaluate the lower extremity arteries. In addition to the standard duplex criteria for classification of carotid stenosis, new criteria are available that reflect the stenosis thresholds identified in randomized clinical trials. Clinical experience has clearly shown that carotid endarterectomy can be performed safely based on the duplex scan alone in the majority of patients: however, arteriography is still indicated in selected cases. The evaluation of lower extremity arterial disease requires examination of multiple arterial segments, and most vascular surgeons still rely on the anatomic detail provided by arteriography for preoperative planning. Still, it may be possible to avoid formal preoperative arteriography in selected patients by using a combination of lower extremity duplex scanning and intraoperative arteriography. Further developments in noninvasive testing will continue to reduce the need for diagnostic arteriography prior to direct arterial surgery.

Predictive ability of duplex ultrasonography for internal carotid artery stenosis of 70%-99%: a comparative study

This study prospectively compared the accuracy of published duplex ultrasonographic criteria for 70%-99% internal carotid artery (ICA) stenosis according to the North American Symptomatic Carotid Endarterectomy Trial (NASCET) method to determine angiographic stenosis. From March 1, 1995 to December 1, 1995, all patients considered for carotid endarterectomy (CEA) were studied with carotid duplex ultrasound and carotid angiography within 1 month of the ultrasound study. Duplex measurements of ICA peak systolic velocity (PSV), end diastolic velocity (EDV), and ratio of the ICA to common carotid artery (CCA) PSVs were recorded. Degree of stenosis on angiography was determined using NASCET criteria. A MEDLINE search to identify duplex ultrasound criteria to predict NASCET defined 70%-99% ICA stenosis was carried out. In addition, the original University of Washington criteria for critical stenosis (> or = 80%) was also examined. The accuracy of these criteria was determined with angiographic results and the positive predictive value (PPV) of each criterion were compared. Ninety-nine patients with 185 carotid bifurcations were available for comparison. The different duplex criteria for determining NASCET defined 70%-99% ICA stenosis were: ICA PSV > 175 cm/sec or PSV < 40 cm/sec, PSV > 230 cm/sec, ratio of ICA to CCA PSVs > 4, PSV > 130 cm/sec plus EDV > 100 cm/sec, and PSV > 270 cm/sec plus EDV > 110 cm/sec. When compared with angiography, the calculated PPVs for these criteria were 71% (73/103), 81% (71/88), 86% (67/78), 88% (62/70), and 90% (57/63), respectively. The University of Washington criteria for critical stenosis (PSV > 125 cm/sec plus EDV > 135 cm/sec) had the highest PPV at 91.6% (55/60). The University of Washington criteria for critical stenosis had the highest PPV to predict a 70%-99% angiographic stenosis.

Prophylactic carotid endarterectomy without arteriography in patients without hemispheric symptoms: surgical morbidity and mortality and long-term follow-up

Between January 1980 and December 1992, 75 prophylactic carotid endarterectomies (CE) were performed on 72 asymptomatic patients presenting high-grade stenosis of the internal carotid artery (ICA). In all patients preoperative assessment consisted of continuous Doppler or duplex scanning. There were 33 women and 39 men with a mean age of 66 +/- 7 years. Surgical exploration confirmed high-grade ICA stenosis in all patients. Mean transstenotic gradient and residual carotid stump pressure determined in 24 patients were 34 +/- 25 mmHg and 51 +/- 20 mmHg, respectively. Combined operative mortality and neurologic morbidity was 1.3% (one death, no permanent neurologic defect). At 5 years, 74% +/- 8% of patients were free of neurologic complications, 89% +/- 8% of patients were free of neurologic complications affecting the ipsilateral cerebral hemisphere, and actuarial survival was 75% +/- 8%. Most deaths were due to heart-related causes. Multivariate analysis showed that hypertension, age, recurrent stenosis, and contralateral stenosis greater than 50% were risk factors for neurologic complications. When only ipsilateral complications were considered, only hypertension was a risk factor. Based on the results of this study, we conclude that prophylactic CE based only on continuous Doppler or duplex scanning is a reliable and safe procedure. Prophylactic CE was effective in avoiding long-term neurologic complications due to ipsilateral hemispheric lesions. However, the higher incidence of contralateral neurologic complications suggests that close surveillance of contralateral lesions is necessary.

Can duplex ultrasonography select appropriate patients for carotid endarterectomy?

OBJECTIVES

This study investigated the reliability of carotid duplex ultrasound (DUS) to identify appropriate candidates for carotid endarterectomy (CEA) according to a panel of vascular specialists.

DESIGN

Prospective study.

MATERIAL

102 patients with 145 carotid bifurcation stenosis or occlusions.

METHODS

All patients who required a carotid angiogram were evaluated using DUS followed by carotid angiography. A blinded panel of four vascular specialists individually decided whether CEA would be appropriate for each patient based on pre-angiographic information. Angiograms were then shown to panelists to see if their management decision was altered by the angiogram.

RESULTS

For stenosis > or = 80% on DUS (n = 60), panelists unanimously agreed on CEA without angiography in 57 lesions. In 50 lesions (87.7%), angiography showed > or = 70% stenosis and the management plan remained unchanged. For the other seven lesions, intracranial aneurysms (n = 2), tandem intracranial lesion (n = 1), unsuspected proximal common carotid lesion (n = 1), a 40% stenotic lesion (n = 1), and high carotid bifurcations (n = 2) were seen. In lesions with 50-79% stenosis on DUS (n = 66), none of the panelists recommended CEA without prior angiography. Eighteen (27%) of these lesions were > or = 70% stenosed on angiogram. Complications of angiograms included one stroke, one haematoma, and one severe allergic reaction.

CONCLUSION

Carotid duplex ultrasonography without angiography can reliably select lesions appropriate for surgery only when critical stenosis > or = 80% is chosen. Routine angiography is recommended for carotid stenosis of 50-79% when CEA is considered.

Cost savings associated with the nonroutine use of carotid angiography

BACKGROUND

To evaluate the economic impact of performing carotid endarterectomy based only on a diagnosis of duplex scanning, we evaluated a cohort of patients treated at our institution during 1 calendar year.

METHODS

Ninety-seven patients were evaluated and divided into two groups: those with and without arteriogram prior to their operation. Duplex scan and arteriogram results were reviewed to determine their effect on the operative plan. Hospital charges and physician fees were assessed for each patient admission. Operative results, complications, and total charges were compared between the two groups.

RESULTS

There was one operative stroke in each group for a stroke rate of 2%. Angiographic complications included one stroke and one femoral artery thrombosis. Two arteriograms led to a change in the operative plan. The hospital charges for patients without an arteriogram was $10,292 verses $13,906 for patients with an arteriogram (P < 0.01). Physician charges for patients without an arteriogram were $3,882, with angiograms and $6,297. The total charges related to the endarterectomy were $14,174 and $20,203, respectively. Arteriograms accounted for an increase of 43% in total charges.

CONCLUSION

Nonroutine use of angiography does not increase operative risk or postoperative length of stay, and preoperative angiography increases total charges by 43% ($6,029) per patient.

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

Traditional surgical practice and published consensus statements from major vascular surgery specialty societies have considered contrast arteriography to be a routine part of the diagnostic evaluation prior to carotid endarterectomy (CEA). However, some surgeons now omit routine preoperative arteriography if a technically adequate carotid duplex scan is performed and indications for CEA are clear. To better establish current practice patterns and to characterize vascular surgeons' opinions about the role of preoperative arteriography, the Peripheral Vascular Surgery Society membership was surveyed by mail. Eighty-six percent of the members responded (430 of 502). Ninety-three percent of all patients considered for CEA are evaluated with duplex scanning; 82% with arteriography. While the majority of surgeons typically obtain both a duplex scan and an arteriogram, 70% have performed CEA without a preoperative arteriogram. Brain imaging studies (CT or MRI) are obtained in 26% and MR angiograms in 10% of cases. Seventy-five percent of the surgeons agreed with the statement that CEA without preoperative arteriography is an acceptable practice if appropriate indications for surgery are present. Furthermore, one third believed that CEA without a preoperative arteriogram is generally acceptable (acceptable more than half the time). Respondents were stratified by surgical experience time in practice and practice type. No significant differences in responses were found, suggesting the acceptance of CEA without preoperative arteriography is broad-based. This survey demonstrates changing attitudes among practicing vascular surgeons regarding the necessity for routine arteriography prior to CEA. Carotid endarterectomy on the basis of duplex scanning and clinical assessment should be considered an accepted alternative.

Cost-efficient carotid surgery: a comprehensive evaluation

PURPOSE

This study was performed to determine whether comprehensive cost-cutting strategies adversely affect the outcome in patients undergoing carotid endarterectomy.

METHODS

From December 1994 to December 1995, 237 consecutive patients undergoing 260 carotid endarterectomies were prospectively studied. The following variables were assessed: carotid arteriography, preoperative laboratory tests, electrocardiograms and chest x-ray films, use of carotid shunts during operation, use of pathology department, intensive care, oxygen therapy, telemetry, and hospital stay. In addition, complications were tabulated.

RESULTS

Previously, all variables evaluated were routinely ordered. Subsequent to initiating the cost-containment strategies, the following results were achieved: arteriography in 52 (22%) of 237 patients, preoperative complete blood cell count and SMA-7 in 161 (62%) of 260 cases, preoperative electrocardiograms in 185 (71%) of 260 cases, preoperative chest x-ray films in 190 (73%) of 260 cases, carotid shunts in 83 (32%) of 260 cases, disease in no cases (0%), intensive care in 29 (11%) of 260 cases, oxygen therapy in 34 (13%) of 260 cases, telemetry in 17 (7%) of 260 cases, and hospital stay was decreased from an average of 2.6 to 1.3 days. Total savings based on average hospital and physician charges was $2.3 million. Complications included four strokes, one myocardial infarction, and no deaths. No patient required readmission. No recurrent or new neurologic or cardiac findings were identified clinically in follow-up at 1 and 4 weeks after surgery.

CONCLUSIONS

The results clearly demonstrate that comprehensive cost-cutting strategies can reduce charges significantly while maintaining patient safety.

Accuracy of duplex sonography before carotid endarterectomy--a comparison with angiography

OBJECTIVES

The aim of this prospective study was to contribute to the evaluation of the reliability of Duplex sonography (DS) before carotid endarterectomy (CEA).

DESIGN

The study was performed prospectively in a university hospital setting.

METHODS

Eighty-one consecutive patients aged 49-83 years were examined with DS and carotid angiography (CAG) before CEA. The results of the DS were judged as either confident, or CAG was assessed to be necessary preoperatively. The results from the DS and the CAG were then compared.

RESULTS

DS was judged as confident in 148 of the 162 arteries examined. In none of these 148 arteries did CAG change patient management in any way, and the agreement between DS and CAG was good. In the remaining 14 arteries CAG was judged necessary, in 11 arteries because DS assessed the internal carotid artery (ICA) as occluded, which was confirmed by CAG in 10 arteries. In three arteries the reason was poor quality of the DS, however these three arteries were correctly assessed as severely diseased.

CONCLUSIONS

This study confirms that DS alone is sufficient in the preoperative evaluation before CEA, provided that CAG is performed whenever DS shows occlusion of the ICA, or when the quality of the DS is poor.

The relative contributions of carotid duplex scanning, magnetic resonance angiography, and cerebral arteriography to clinical decisionmaking: a prospective study in patients with carotid occlusive disease

PURPOSE

Recent reports suggest that 80% to 90% of patients can safely undergo carotid endarterectomy on the basis of duplex scanning alone without cerebral angiography. Other investigators have recommended that a complementary imaging study such as magnetic resonance angiography (MRA) also be obtained.

METHODS

We prospectively evaluated 103 consecutive patients with carotid occlusive disease. Eighty percent of patients were symptomatic. All 103 patients underwent duplex scanning and arteriography. Additional noninvasive tests included computed tomography, magnetic resonance imaging, and MRA in 50%, 56%, and 48% of patients, respectively. At a multispecialty conference all studies except angiograms were reviewed, and a treatment decision was made by a panel of attending vascular surgeons, neurosurgeons, and neurologists. The cerebral angiograms then were reviewed and changes made to final treatment plans were noted.

RESULTS

After review of noninvasive studies, 30 of 103 of patients (29%) were believed to require arteriography because of diagnostic uncertainty of carotid occlusion in three patients, suggestion of nonatherosclerotic disease in four, suggestion of proximal disease in two, suboptimal noninvasive studies in one, and uncertainty of therapy despite good-quality noninvasive studies in 20 patients primarily with borderline stenoses and unclear symptoms. In 10 of these 30 patients (33%) management decisions were changed on the basis of angiogram results. Of the remaining 73 patients (71%) in whom the panel felt comfortable proceeding with operative or medical therapy without angiography, only one patient (1.4%) would have had management altered by results of angiography. MRA results concurred with duplex findings in 92% of studies, but did not alter management in any patient.

CONCLUSIONS

In patients with good-quality duplex images, focal atherosclerotic bifurcation disease, and clear clinical presentation, treatment decisions can be made without arteriography. In 30% of patients angiography is useful in clarifying decisionmaking. MRA is unlikely to influence management decisions and is thus rarely indicated.

Carotid endarterectomy without arteriography: the preeminent role of the vascular laboratory

The classic workup of patients considered for carotid endarterectomy (CE) has included contrast arteriography to delineate the nature and extent of the arterial pathology. Noninvasive testing (NIT) consisting of duplex scanning plus sound spectrum analysis is an alternative method for accurately evaluating the carotid bifurcation. The accuracy of our laboratory in comparing NIT to contrast arteriography has been established by use of the guidelines suggested by the Intersocietal Commission for the Accreditation of Vascular Laboratories. Forty-two patients underwent CE based on NIT alone. Seventeen had hemispheric transient ischemic attacks or minor strokes, six had amaurosis fugax, three had nonspecific symptoms, and 16 were asymptomatic. NIT identified a severe stenosis that was limited to the carotid bifurcation; the internal carotid artery distal to the bulb was normal. The predicted stenotic atherosclerotic lesion was confirmed at operation in all patients. One patient had a high bifurcation that required an extension of the original incision. Of three undiagnosed kinked distal internal carotid arteries found at operation, only one required surgical correction. No transient ischemic attacks, strokes, or deaths occurred postoperatively. CE can be performed in selected patients based on NIT alone, obviating the mortality, morbidity, and cost of arteriography. This algorithm demands that the NIT is unequivocal and the accuracy of the testing laboratory is established and maintained according to published standards.

Carotid endarterectomy without arteriography

Arteriography has been considered the "gold standard" for evaluation of the cerebrovascular circulation prior to carotid endarterectomy. However, arteriography is associated with a neurologic complication rate of up to 12% in certain high-risk groups. Previous studies have shown that the duplex scanner has greater sensitivity than arteriography when both are correlated to the surgical specimen. From January 1986 to December 1991 a total of 174 carotid endarterectomies were performed in 152 patients, of which 61% were symptomatic. A total of 110 carotid endarterectomies in 92 patients were performed without the use of arteriography. Of the 64 patients in whom arteriograms were obtained, 33 were made at consultation and the others for various indications. Operative findings confirmed the duplex scan findings in all cases. A total of 91% of patients had intraoperative completion arteriograms. Of the 55 patients who also had intracranial views taken, two had a 50% siphon stenosis and one patient had a small intracranial aneurysm. None of these findings would have changed our management. The overall neurologic complication rate was one (0.66%) death due to stroke and four (2.6%) patients with transient ischemic attacks. Carotid endarterectomy can be safely performed without preoperative arteriography based on a detailed history and physical examination that includes bilateral upper extremity blood pressures and a duplex scan performed by a validated laboratory.

Carotid artery occlusion: positive predictive value of duplex sonography compared with arteriography

PURPOSE

Duplex ultrasonography is an accurate, noninvasive method for diagnosing, characterizing, and classifying atherosclerotic stenoses of the extracranial carotid artery system. To date, however, no large series has studied the predictive value of duplex sonography in the diagnosis of carotid artery occlusion, an important consideration, given the marked difference in clinical treatment between patients with high-grade stenosis (surgical therapy) and those with occlusive disease (nonsurgical therapy).

METHODS

We retrospectively reviewed 158 patients with 174 occluded carotid artery segments (examined over a 6 1/2-year period) to determine the predicative value of duplex sonography in differentiating carotid artery occlusion from high-grade stenosis.

RESULTS

All patients had arteriographic correlation. Duplex ultrasonography had a positive predictive value of 92.5% (7.5% false-positive rate; 95% confidence interval, 3.6% to 11.4%) in establishing a diagnosis of carotid artery occlusion. Further analysis revealed no significant improvement in the false-positive rate with the addition of color Doppler flow imaging to high-resolution B-mode scanning and pulsed Doppler spectral analysis. Predictive value increased to 96.7% (95% confidence interval, 90.7% to 99.3%) over the last 2 years of the study, a statistically significant improvement.

CONCLUSIONS

We believe that duplex ultrasonography is an acceptably accurate method for diagnosing carotid arterial occlusion in most patients. Arteriography should be reserved for patients with symptoms who are surgical candidates to identify those who may still have a surgically correctable high-grade stenosis.

Carotid endarterectomy after noninvasive evaluation by duplex ultrasonography and magnetic resonance angiography

Recent studies documenting the efficacy of carotid endarterectomy (CEA) in selected patients provide further impetus for developing noninvasive techniques to evaluate carotid occlusive disease. Eliminating the morbidity due to preoperative angiography would further refine the treatment of this condition. Recent improvements and greater experience with magnetic resonance angiography (MRA) of extracranial vessels have increased the accuracy of this technique. We present our experience using MRA in combination with duplex ultrasonography as the primary mode of preoperative evaluation for CEA. Fifty-two patients referred for CEA underwent these two studies. In 47 patients (90%), significant stenosis (> 70%) was unambiguously identified on both ultrasound and MRA. Forty-one of these patients underwent CEA on the basis of these studies alone, without conventional angiography. In all of these cases, significant stenosis was identified at the time of surgery (100%), and CEA was performed without difficulty or complications. In five cases (9.6%), the MRA and ultrasound findings did not concur exactly. In three of these cases, the interpretation of the two studies differed with respect to the severity of stenosis; in the others, one of the studies was indeterminate. These patients underwent conventional angiography before surgery. Our experience suggests that the combined use of MRA and ultrasonography affords an accurate noninvasive evaluation of carotid occlusive disease sufficient for surgical planning in most cases.

Are both color-flow duplex scanning and cerebral arteriography required prior to carotid endarterectomy?

In an attempt to eliminate the morbidity, mortality, and cost associated with arteriography, surgeons are relying increasingly on duplex scanning of the extracranial arteries as the primary preoperative evaluation prior to carotid endarterectomy (CEA). This study was initiated to evaluate the need for cerebral arteriography in the preoperative evaluation of patients for CEA. One hundred five patients undergoing 114 CEA procedures are included in a retrospective review to determine whether the addition of cerebral arteriography changed the operative management of these patients. In 58 of 105 patients (55%), color-flow duplex scanning and cerebral arteriography were performed in the workup prior to CEA. In four patients a discrepancy was found between the duplex results and the arteriogram, leading to a change in the operative approach in two. The remaining 47 patients (45%) underwent color-flow duplex scanning as the definitive preoperative study; the surgical management was altered because of the operative findings in one patient. Although color-flow duplex scanning does not provide absolute concordance with cerebral arteriography, in most instances it can be used as the definitive preoperative study prior to CEA. We define the indications for cerebral arteriography in patients undergoing CEA.

Identifying total carotid occlusion with colour flow duplex scanning

A major limitation of conventional duplex scanning is its inability reliably to differentiate severe stenosis from total occlusion of the internal carotid artery (ICA). Colour flow duplex scanning (CFS) facilitates the identification of internal and external carotid arteries, enables simultaneous evaluation of flow in multiple vessels in longitudinal and transverse views, and allows more accurate assessment of very low Doppler-shift frequencies with new "slow-flow" software technology. From July 1987 to January 1991, 9731 ICAs (4866 patients) were evaluated with CFS. Arteriography was performed in 483 of these patients (959 ICAs), and the results of the two studies were compared. Colour flow scanning was highly accurate in differentiating total occlusion from carotid stenosis. Eighty-two of 87 totally occluded ICAs were detected (sensitivity 94%) and 873 of 878 patient arteries were properly identified (specificity 99%). Positive and negative predictive values were 93 and 99%, respectively. False positive results (n = 6) were due to interpreter error (n = 4) and poor scanning technique (n = 2). All false negative results (n = 5) were the result of interpreter error. During the last 24 months of the study, no false positive or false negative results were detected, giving an accuracy of 100%. We conclude that CFS offers distinct advantages in the diagnosis of carotid occlusion, thereby overcoming the limitations of conventional duplex scanning in distinguishing total occlusion of the ICA from less severe disease, and is the method of choice for evaluating the carotid bifurcation.

Persistent hypoglossal artery: An anomaly leading to false-positive carotid duplex sonography

Duplex ultrasonography is becoming increasingly popular as the sole diagnostic test in the evaluation of carotid artery bifurcation disease. We present a patient with a persistent hypoglossal artery, a rare primitive internal carotid-basilar anastomosis, masquerading as an internal carotid artery stenosis on ultrasound. The operative management of this anomaly is reviewed.

Duplex scanning alone before carotid endarterectomy: a 5-year experience

The role of duplex scanning and arteriography as a means of assessing patients for carotid endarterectomy has been reviewed for the period 1984 to 1988 when 98 carotid endarterectomies were performed. Of these 44 were selected for surgery on the basis of duplex assessment alone, 48 after carotid angiography and duplex scanning and six after angiography alone. No difference between the groups of patients was observed for either perioperative or follow-up complication rates, although all late deaths occurred in patients who had been examined by angiography. By the end of the study period angiography was requested for less than 30% of all patients undergoing carotid endarterectomy. It is argued that the change in our practice is safe provided that certain criteria are met. These include angiography in cases of suspected aortic arch or proximal vessel disease and in those symptomatic patients with a duplex diagnosis of complete occlusion.

Role of arteriography in the preoperative evaluation of carotid artery disease

This retrospective study was undertaken to determine the role of arteriography in the treatment of patients being considered for carotid endarterectomy. The results of preoperative classification of disease severity by duplex ultrasound and arteriography were compared, and the impact of arteriography on patient management was ascertained. We reviewed the records of 83 patients who had carotid surgery planned on the basis of their clinical history and duplex scan results and who then underwent arteriography. Duplex scan results agreed with the classification of stenosis by arteriography in 87% of evaluated sides and were within one category in 98%. In 87% of the cases reviewed, the clinical presentation and duplex scan findings were sufficient for appropriate patient management. In the instances that arteriography was useful (13%), the need for arteriography was evident when the duplex scan (1) was technically inadequate or equivocal; (2) showed an unusual distribution of disease, atypical anatomy, or a recurrent lesion; or (3) demonstrated an internal carotid artery with diameter-reducing stenosis of less than 50% in a patient with hemispheric neurologic symptoms despite antiplatelet therapy.

Carotid surgery without arteriography: noninvasive selection of patients

All carotid noninvasive studies at our institution comprised of duplex scanning, spectral frequency analysis, and ocular-pneumoplethysmography-Gee supraorbital Doppler assessments from 1985-1987 were reviewed. Forty symptomatic and 104 asymptomatic internal carotid arteries, concomitantly studied noninvasively and arteriographically, were identified. All studies were rereviewed prospectively and in blinded fashion. Utilizing peak frequency--internal carotid artery greater than 10 mHz and carotid index (Pf-ICA)/PF-common carotid) greater than 5 as criteria for surgery, 39/40 symptomatic internal carotid arteries were considered appropriate for carotid endarterectomy by noninvasive study. All of these internal carotid arteries had arteriographic confirmation of greater than 50% internal carotid artery stenosis; 22 of them met noninvasive criteria for surgery of peak systolic frequency-internal carotid artery greater than 14 mHz, carotid index greater than 7 and abnormal ocular-pneumoplethysmography-Gee/supraorbital Doppler. All of these had arteriographic confirmation of greater than 80% internal carotid artery stenosis. Eleven asymptomatic internal carotid arteries met spectral frequency criteria for carotid endarterectomy but had normal ocular-pneumoplethysmography-Gee/supraorbital Doppler. Eight in this group had less than 80% stenosis on arteriographic exam. Carotid endarterectomy may be performed without prior arteriography, provided objective criteria are established in a reliable noninvasive lab and met by individual patients.

The diminishing role of diagnostic arteriography in carotid artery disease: duplex scanning as definitive preoperative study

In an effort to eliminate the inherent neurologic morbidity associated with arteriographic investigation, we have increasingly relied upon duplex scans of the extracranial carotid arteries prior to endarterectomy. The percentage of patients undergoing carotid endarterectomy without arteriograms has increased from 5% in 1984 to 69% during 1988-1989. Initially, carotid endarterectomy without arteriography was limited to patients with hemispheric symptoms and relative contraindications. Over the course of the study from 1984-1989, indications for operation were similar for patients having carotid endarterectomy on the basis of duplex scan alone or following arteriography. The perioperative outcome for these patients undergoing duplex scan (n = 255) and arteriography (n = 484) were similar for stroke (2.4%) versus 2.7%, p = NS) and death (0% versus 0.4%, p = NS). Stratification of groups by indication did not show any significant differences in outcome. Duplex scans were sufficiently accurate to replace preoperative arteriograms in identifying significant stenoses at the carotid bifurcation, including asymptomatic disease. Lack of information regarding intracranial arterial occlusive disease did not adversely affect perioperative outcome. Carotid arteriography can be used selectively when duplex scans are technically difficult, when physical examination or scans suggest either inflow (arch) disease or diffuse, distal internal carotid plaque, or when cerebral symptoms are not sufficiently explained by duplex findings.

Can duplex scanning replace arteriography for lower extremity arterial disease?

This preliminary study was undertaken to determine if surgeons would choose different intervention for lower extremity occlusive disease when given basic clinical information and data from either a duplex scan or arteriogram. Information on degree of stenosis from duplex scans and arteriograms of 29 patients was indicated on an anatomical line drawing along with the ankle blood pressures and a brief clinical description. Based on these data sheets, six vascular surgeons chose a clinical plan in a blinded fashion for each patient. Each plan was placed into one of eight possible categories for comparison using the kappa statistic. Intraobserver agreement between surgeons' decisions based on duplex scanning versus those based on arteriography was very good (mean kappa .70 with exact agreement in 76%). Interobserver agreement between different surgeons' decisions based on the same studies was significantly less (mean kappa 0.56, p less than .05). Significant disparity in clinical approach occurred in 43% of the patients with nearly identical duplex scan and arteriogram reports, suggesting that much of the discrepancy lies in the clinical decision-making process. Clinical decisions made using duplex scans are very similar to those made using arteriograms. This technique can limit the need for arteriography in assessing patients with lower extremity arterial occlusion disease.

Role of duplex scanning in the selection of patients for carotid endarterectomy

A retrospective review of 63 patients undergoing duplex scanning and angiography for suspected carotid artery disease was performed to evaluate the need for routine angiography before carotid endarterectomy. A consultant surgeon (M.H.) made a simulated management decision on the basis of a clinical summary and a duplex scan report. Twenty-four patients were selected for surgery without angiography; duplex scanning had a sensitivity of 100 per cent and a specificity of 90 per cent in the detection of internal carotid artery stenosis. In two cases duplex scanning misdiagnosed a total occlusion as a critical stenosis. Eighteen patients failed to meet the criteria for surgery and were referred for angiography. Twenty-one patients were selected for conservative treatment on the basis of the duplex scan report. Combining the surgical and conservative groups (45 patients), duplex scanning had a sensitivity of 96 per cent and specificity of 95 per cent for the detection of stenosis greater than 50 per cent. In the identification of a total occlusion, duplex scanning had a poor sensitivity of 50 per cent. These results suggest that routine angiography before carotid endarterectomy is unnecessary in selected patients but that a suspected occlusion should be confirmed by angiography.

Carotid endarterectomy without angiography

Carotid endarterectomy without preoperative angiography is a viable alternative that avoids the risk of angiography and potentially reduces the overall morbidity and mortality associated with the workup of patients with carotid artery disease and surgical management. The success of this approach is dependent upon the accuracy of the history and physical examination, acquisition of a CT head scan, and the validity of the duplex scan in a given laboratory.

Safe extracranial vascular evaluation and surgery without preoperative arteriography

Carotid surgery without preoperative arteriography was performed in 101 consecutive patients with an average age of 68.5 years and almost equal sex distribution. This prospective study analyzed risk factors, operative approach, bruits, indications for surgery, and outcome. All patients were studied by real-time B-mode ultrasound and spectral analysis and none were referred for arteriogram. The majority of patients had a standard carotid endarterectomy, and the findings at surgery correlated with noninvasive imaging. No mortality was recorded in this series of patients; a 1% rate of neurologic morbidity was noted. These results suggest that one can safely operate on the basis of a duplex scan. A preoperative arteriogram is not always necessary for carotid evaluation.

Evaluation of ulceration in the extracranial carotid artery with ultrasonography: a comparison with arteriography

The accuracy of duplex-scanning and angiography in detecting ulceration in the carotid arteries was evaluated. Sixty-nine patients underwent duplex-scanning and carotid arteriography, and the findings were blindly compared to the operative specimens. Duplex-scanning had a significantly higher sensitivity (90 vs 48%, P less than 0.001) and accuracy (88 vs 59%, P less than 0.001) than angiography. There was no difference in specificity (84 vs 89%, P = 0.28). Comparison was also made between conventional arch angiography and selective carotid angiography in detecting ulceration. There was no significant difference between the methods (sensitivity 47 vs 50%, specificity 82 vs 100%). Finally, interobserver variability in detecting ulceration with duplex-scanning was evaluated in double-blind evaluation of the duplex-scans. The interobserver agreement was 84%. Duplex-scanning seems to be superior to angiography in detecting ulcerations in the extracranial carotid artery.

Can clinical evaluation and noninvasive testing substitute for arteriography in the evaluation of carotid artery disease?

The objective of this study was to prospectively assess the value of combining clinical assessment and noninvasive testing in predicting the spectrum of carotid bifurcation pathology, as subsequently proven by arteriography, in order to determine the safety and accuracy of performing carotid endarterectomy without angiography. A panel of eight specialists representing vascular surgery, neurology, and neurosurgery were presented with the history, physical findings, and noninvasive test results (GEE-OPG and duplex scan) of 85 patients. They were asked to make an anatomic prediction of the status of each carotid artery (170 arteries) as to whether the bifurcation was normal, ulcerated, had a hemodynamically significant stenosis, or was occluded. The predictions were then prospectively evaluated and correlated with angiographic findings; 159 of 170 (93.5%) carotid arteries were accurately characterized; 73 of 80 (91%) symptomatic carotid arteries and 86 of 90 (95.5%) asymptomatic arteries were correctly characterized; 61 of 61 (100%) stenoses of hemodynamic significance, nine of 14 (64.3%) ulcerations without stenosis, and 18 of 18 (100%) of total occlusions were accurately identified by the panel. Twenty-nine patients have subsequently had 32 carotid endarterectomies without angiography, and the predicted lesion was confirmed at the time of exploration. The combination of clinical assessment and noninvasive testing, particularly duplex scanning, when performed in a laboratory with validated accuracy may with defined qualification be safely used as a substitute for contrast angiography.

Use of diastolic velocity ratios to predict significant carotid artery stenosis

Duplex scanning of the carotid bifurcation has emerged as an accurate noninvasive means of predicting and quantifying carotid arterial stenoses. Compared with the more widely reported measurements of spectral broadening and peak frequency ratios, measurements of diastolic velocity ratios have theoretical advantages in predicting carotid artery stenosis. The use of diastolic velocity ratios between the internal and common carotid arteries was prospectively studied in 30 consecutive patients to determine its accuracy in predicting significant stenosis of the internal carotid artery when compared with angiography. A total of 55 carotid bifurcations were studied, and the use of diastolic velocity ratios correctly predicted high-grade stenosis (greater than or equal to 75% diameter reduction) in 52 cases (95%). We conclude that diastolic velocity ratios may be used to accurately detect significant internal carotid artery stenosis.

The limitations of diagnosis of carotid occlusion by Doppler ultrasound

Duplex scanning has been advocated as an acceptable alternative to angiography in the preoperative evaluation of carotid artery stenosis. To evaluate the accuracy of carotid Doppler in differentiating severe carotid stenosis from occlusion, we compared the results of angiography with duplex scanning in 124 carotid arteries (62 patients) and with continuous-wave Doppler in 662 carotid arteries (331 patients). The specificity was 95-99%, sensitivity was 86-96%, and accuracy was 95-98%. Duplex scanning wrongly identified occlusion in four arteries and failed to detect occlusion in one artery. In making decisions prior to carotid endarterectomy, even infrequent errors are unacceptable. We recommend angiography of all surgical candidates with apparent severe stenosis when the internal carotid artery cannot be clearly identified on duplex, or to distinguish apparent occlusion from undetectably low blood flow.