Intraoperative duplex ultrasonography as an adjunct to technical excellence in 100 consecutive carotid endarterectomies

PURPOSE: To evaluate the relationship of intraoperative duplex ultrasonography (duplex) results to neurologic outcomes and restenosis among patients undergoing carotid endarterectomy (CEA). METHODS: One hundred consecutive CEAs were performed at a military medical center over 28 months. Prospectively acquired demographics, duplex results, revisions, and surgical outcomes were reviewed. RESULTS: Thirty-four percent (34 of 100) of sites were abnormal by completion duplex. Of these, 70% (24 of 34) were B-mode flap type defects located in the common carotid artery (CCA), internal carotid artery (ICA), or external carotid artery (ECA). Twenty-one percent of the defects (7 of 34) were technically unacceptable and immediately revised. Subsequently, 3 perioperative neurologic events occurred, 2 strokes and 1 transient ischemic attack (TIA), all among patients with an identified but unrepaired defect involving the ICA or CCA. This association of unrepaired defect with early stroke or TIA was significant (P = 0.02). No significant association (P >0.05) between unrepaired defects and late ipsilateral stroke or TIA or restenosis was identified. CONCLUSIONS: Intraoperative duplex scanning is a useful adjunct to CEA that can identify correctable mechanical problems. Residual elevated velocities or B-mode flaps 2 mm or greater in the ICA warrant consideration for immediate repair. Findings not requiring revision include flaps <2 mm, as well as isolated ECA defects. Prospectively validated duplex criteria are needed to further define which defects require immediate repair.     

Accuracy of duplex scanning in the detection of stenosis after carotid endarterectomy

The results of duplex ultrasonography in grading stenosis after carotid endarterectomy (78 sites) were compared with those of contrast angiography in 71 patients studied for recurrent or contralateral occlusive disease of the carotid bifurcation. Duplex and angiographic studies were performed within one month of each other at a mean postoperative interval of 44 months (range 3 to 122 months). Stenosis of the common carotid (CCA) and internal carotid artery (ICA) was classified into five disease categories (normal or less than 15% diameter reduction [DR], 16% to 49% DR, 50% to 75% DR, greater than 75% DR, and occlusion). The overall accuracy of duplex scanning compared with angiography in predicting recurrent carotid bifurcation disease was 83%, a level of agreement similar to classification of disease involving the nonoperated, contralateral bifurcation (overall accuracy 87%). Recurrent stenosis (greater than 50% DR) or occlusion of the CCA or ICA after endarterectomy was identified with an accuracy of 97%. Overestimation of severity of recurrent stenosis accounted for 11 of 13 duplex classification errors (85%). Presence of moderate (30% to 50% DR) recurrent stenosis of the CCA, tortuosity of the ICA, and severe contralateral carotid bifurcation disease were associated with velocity spectra that predicted a more severe recurrent stenosis at the endarterectomy site compared with angiographic grading. The level of agreement between duplex scanning and angiography was comparable to the interobserver variability in angiographic interpretation. The accuracy reported justifies the use of duplex scanning to grade the severity of carotid bifurcation recurrent stenosis and to follow these lesions for disease progression.     

Comparison of Intraoperative and Postoperative Duplex Ultrasound for Carotid Endarterectomy

Intraoperative (IO) duplex ultrasound (DU) is used to identify correctable technical defects at the time of carotid endarterectomy (CEA). Postoperative (p.o.) DU is used to evaluate recurrent or residual stenosis. We compared IO and p.o. DU to determine the value and significance of these studies in the management of patients undergoing CEA. We performed completion IO DU following CEA and p.o. DU a mean of 8 weeks after surgery in 78 patients. IO studies were performed by the operating surgeon and p.o. studies were performed in an accredited vascular laboratory. Peak systolic velocity (PSV) was measured in the internal carotid (ICA), external carotid, and common carotid (CCA) arteries. The criteria used for an abnormal study were an ICA PSV > 150 cm/sec and a ratio of ICA to CCA PSVs(ICA/CCA) > 3.0. Completion angiograms were also performed on all patients intraoperatively. Technical defects identified on DU or angiogram were corrected whenever possible. From our results, we concluded that in many patients, early p.o. DU will demonstrate an elevated ICA PSV compared to the IO PSV. If the ICA/CCA remains normal, this increase is unlikely to represent a clinically relevant recurrent or residual stenosis. A postoperative ICA/CCA ratio > 3.0 may be a more reliable indicator of significant stenosis and a lesion that is likely to progress or occlude than PSVs alone.     

Surgical treatment of internal carotid artery occlusion

PURPOSE: Nonoperative treatment of recent internal carotid artery (ICA) occlusion is associated with increased recurrent stroke rates. We analyzed our results of carotid endarterectomy (CEA) for treatment of symptomatic recent ICA occlusion to evaluate its feasibility, safety, and outcomes. METHODS: From 1990 to 2002, all patients with transient ischemic attack (TIA), amaurosis fugax, and minor stroke underwent duplex ultrasound (US) scanning and arteriography to confirm the diagnosis of ICA occlusion. Within 2 weeks of symptom onset, patients underwent operative exploration with attempted CEA. ICA occlusion was detected at preoperative angiography and confirmed at surgery. Patients with extensive ICA plaque not amenable to endarterectomy underwent external CEA with ICA ligation. RESULTS: Over 12 years, 87 patients with symptomatic ICA occlusion underwent 90 operations for ICA exploration. In 30 patients (18 men, 12 women) with TIA (45%), amaurosis fugax (19%), or minor stroke (36%), CEA to treat ICA occlusion was technically successful. There was 1 postoperative stroke, 2 asymptomatic internal carotid occlusions, and no restenoses (mean follow-up, 26 months; range, 1-93 months). In 57 patients (37 men, 20 women) with TIA (41%), amaurosis fugax (27%), or stroke (32%) in whom CEA was unsuccessful, external CEA was performed. In this group there were no postoperative strokes, 2 asymptomatic external carotid artery occlusions, and 1 restenosis (>70%) (mean follow-up, 22 months; range, 1-73 months). There were no late strokes in either group. CONCLUSION: Operative exploration and endarterectomy to treat symptomatic ICA occlusion is feasible and safe. Patients with symptomatic ICA occlusion should be considered candidates for CEA.     

Cerebral hyperperfusion syndrome after carotid endarterectomy: predictive factors and hemodynamic changes

PURPOSE: It is believed that cerebral hyperperfusion syndrome (CHS) is caused by loss of cerebral autoregulation resulting from chronic cerebral ischemia and that factors including increased intraoperative cerebral blood flow, ipsilateral or contralateral carotid disease, and postoperative hypertension may cause CHS. We describe our experience with CHS, which diverges from published reports. MATERIALS AND METHODS: From March 2000 to February 2002 we performed 455 carotid endarterectomy (CEA) procedures in 404 patients at our institution. CHS developed 1 to 8 days (mean, 3.2 +/- 2.5 days) postoperatively in 9 patients (2%), 6 women and 3 men, whose age ranged from 52 to 84 years (mean, 69 +/- 8 years). Indications for surgery in 8 patients without neurologic symptoms were ipsilateral internal carotid artery (ICA) stenoses ranging from 70% to 99% (mean, 80% +/- 7%); the remaining patient had an ipsilateral stroke, with good clinical recovery, 7 weeks before CEA. Only 1 patient had significant contralateral ICA stenosis (70%). However, 5 patients had undergone contralateral CEA within the previous 3 months. CHS symptoms were severe headache in 5 patients, seizures in 3 patients (1 stroke), and visual disturbance and ataxia in 1 patient. All 404 patients (455 cases) underwent intraoperative and early (2 weeks) postoperative carotid artery duplex scanning. The 9 patients with CHS also underwent carotid artery duplex scanning at the time of the neurologic event. RESULTS: Mean intraoperative ICA volume flow (MICAVF) in the 9 CHS cases was not significantly different from that in the other 446 cases (170 +/- 47 mL/min and 182 +/- 81 mL/min, respectively). However, mean ICA volume flow (481 +/- 106 mL/min) and peak systolic velocity (PSV) (108 +/- 33 cm/s) for the 9 CHS cases measured at onset of symptoms were higher than those for the remaining 446 cases (267 +/- 87 mL/min and 80 +/- 26 cm/s, respectively) (P <.01). Of the 9 patients with CHS, only 3 had systolic blood pressures more than 160 mm Hg at onset of symptoms. Severity of ipsilateral and contralateral ICA stenoses was not significantly different between the 9 CHS cases and the remaining 446 cases. CONCLUSIONS: These data do not corroborate the common belief that CHS occurs preferentially in patients with severe ipsilateral or contralateral carotid disease, increased intraoperative cerebral perfusion, or severe hypertension. Recently performed contralateral CEA (<3 months) appears to be predictive of CHS.     

Routine early postoperative duplex scanning is unnecessary following uncomplicated carotid endarterectomy

Although early postoperative duplex scanning has become routine after carotid endarterectomy (CEA), it is unclear whether the results of these scans alter clinical management. The purpose of this study was to critically examine the usefulness of early postoperative duplex scans in evaluating the ipsilateral carotid artery (for technical perfection) as well as the contralateral carotid artery (for potential velocity changes after improvements in ipsilateral flow). Consecutive patients undergoing CEA between January 1995 and June 1999 in a tertiary hospital setting were studied. Patients underwent early postoperative duplex scanning according to the discretion of the operating surgeon and the availability of the patient. In 212 patients 236 CEAs were performed with selective use of patch closure (49%), intraluminal shunting (19%), and intraoperative completion imaging studies (14%). Neurologic complications included 3 transient ischemic attacks (TIAs) (1.3%), 3 nondisabling strokes (1.3%), and 3 disabling strokes (1.3%). There was 1 30-day death from myocardial infarction. Patients were followed up for a median of 18 months (range 0-72 months). Sixty-five percent of patients undergoing uncomplicated CEA (147/227) underwent early duplex surveillance within 6 months of operation. Unsuspected sonographic abnormalities were discovered in 8 patients (5%), including 7 cases of mild internal carotid artery (ICA) stenosis (>50% by velocity criteria) and 1 case of common carotid artery (CCA) stenosis (intimal flap). None of the patients with ICA stenosis developed symptoms or required operation at any time. The CCA intimal flap was electively repaired without complication. Postoperative changes in velocity in the contralateral ICA were found in 8/48 (17%) cases. There were 3 cases of increased velocity, upgrading 1 from 0-49% to 50-79% stenosis and upgrading 2 from 50-79% to 80-99% stenosis. The latter patients both underwent uneventful contralateral CEA. There were 6 cases of decreased velocity, resulting in downgrading of stenoses from 50-79% to 0-49% (n=5) or from 80-99% to 50-79% (n=1). Only the latter patient underwent contralateral CEA; the remainder have been followed up without intervention. Early scanning appeared to offer no clinical benefit; survival and neurologic outcome were the same in the 135 patients scanned within the first 6 months as in the 68 patients whose first postoperative scan occurred later (4-year neurologic event rate 0% in both groups; patient survival with early duplex 98 +/- 1.5%, without early duplex 96 +/- 2.6%; = NS). Early ipsilateral duplex abnormalities following CEA are infrequent in asymptomatic patients and, even if found, rarely alter management. Patients with bilateral stenosis being considered for contralateral CEA should undergo repeat duplex scanning after the first operation, because of the significant rate (19%) of contralateral velocity changes induced by ipsilateral CEA.     

The importance of Doppler angle of insonation on differentiation between 50-69% and 70-99% carotid artery stenosis.

AIM: to investigate the importance of Doppler angle differentiating between 50-69% and >/=70% internal carotid artery (ICA) stenosis. MATERIAL AND METHODS: fifty-one patients with a previous diagnosis of 50-69% ICA stenosis (n =53) were re-evaluated by duplex scanning. Spectral Doppler velocity waveforms were obtained from common carotid (CCA), ICA and external (ECA) carotid arteries with the same Doppler angle of insonation as used at the initial duplex scanning, followed by repeated measurements with a fixed 60 degrees angle of insonation. RESULTS: the peak systolic velocity (PSV) in the ICA was 181+/-55 cm/s (mean+/-SD) at the second duplex scanning when the same angle of insonation (mean 46 degrees +/-9) was used as during the initial investigation. When the examination was done with a 60 degrees angle of insonation, PSV ICA was 261+/-96 cm/s (mean+/-SD). In fifteen arteries the estimated degree of ICA stenosis changed from 50-69% to 70-99% due to the application of a fixed Doppler angle of insonation at 60 degrees. CONCLUSION: the Doppler angle of insonation has a significant effect on spectral Doppler velocity measurements. It is crucial that duplex criteria are standardised with a fixed angle of insonation and that this angle is consistently used during velocity estimations.     

Is a single preoperative duplex scan sufficient for planning bilateral carotid endarterectomy?

PURPOSE: Duplex scanning is often the sole imaging study before carotid endarterectomy (CEA). Patients with bilateral severe internal carotid artery (ICA) stenosis may be considered for bilateral CEA. High-grade ICA stenosis, however, may artifactually elevate velocity measurements used to quantify stenosis in the contralateral ICA. It is unknown whether ipsilateral CEA will influence duplex determination of the presence of a contralateral 60% to 99% ICA stenosis. This study was performed to determine whether a single preoperative duplex scan is sufficient to plan bilateral CEA. METHODS: Preoperative and early postoperative carotid duplex scans in patients with bilateral ICA stenosis who underwent unilateral CEA were reviewed. Changes in duplex scans that determined stenosis in the ICA contralateral to the CEA were analyzed. Previously validated criteria used to determine 60% to 99% ICA stenosis were a peak systolic velocity (PSV) of 260 cm/sec or more combined with an end diastolic velocity (EDV) of 70 cm/sec or more. RESULTS: Over an 8-year period, 460 patients underwent CEA; 107 patients (23.3%) had an asymptomatic 50% to 99% contralateral ICA stenosis by standard criteria (PSV, >125 cm/sec) and an early postoperative duplex scan examination. Of these 107 patients, 38 patients (35.5%) had duplex scan criteria for 60% to 99% contralateral ICA stenosis. In these 38 patients, there was a mean postoperative PSV decrease of 47.7 cm/sec (10.1%) and a mean EDV decrease of 36.0 cm/sec (19.3%) in the ICA contralateral to the CEA. Eight of 38 (21.1%) preoperative contralateral 60% to 99% ICA lesions were reclassified as less than 60% on postoperative duplex scanning. Six of 69 (8.7%) preoperative lesions of less than 60% were reclassified as 60% to 99% on postoperative duplex scan. These six preoperative examinations were all close to the criteria for 60% to 99% stenosis (mean PSV, 232.5 cm/sec; mean EDV, 62.5 cm/sec). CONCLUSION: One-fifth of patients with apparent 60% to 99% contralateral ICA lesions before the operation have less than 60% stenosis when restudied with duplex scan after unilateral CEA. Lesions below but near the cutoff for 60% to 99% may be reclassified as 60% to 99% on the postoperative duplex scan. These findings mandate that when duplex scanning is used as the sole imaging modality before CEA, patients with severe bilateral carotid stenosis must have an additional carotid duplex examination before operation on the second side.     

Outcome of progression from carotid stenosis to occlusion.

The incidence of symptoms at the moment the internal carotid artery (ICA) occludes was assessed in 33 patients. Duplex scanning was performed to determine the progression from stenosis to ICA occlusion. There were 24 patients with a primary stenosis and nine with a restenosis after a carotid endarterectomy. In 18% (6/33) the occlusion was accompanied by a stroke. A transient ischaemic attack (TIA) was seen in 12% (4/33) of patients and 70% (23/33) remained asymptomatic. There was no difference in stroke rate between patients with primary stenosis (4/24:17%) and those with restenosis (2/9:22%). The mean follow-up was 3.2 years and the mean elapse time to occlusion in patients with a stroke was 20 months, with a TIA, 32 months, and in asymptomatic patients, 44 months. It was also shown that a stenosis of greater than 80% diameter reduction had a faster progression (mean 1 year) than a less than 80% stenosis (mean 3.5 years) (p = 0.04). Patients with a stenosis greater than 80% tended to have a higher incidence (40%:2/5) of stroke at the time of occlusion than patients with a stenosis less than 80% (14%:2/28). The results show that an occlusion of the ICA is accompanied by a stroke in 18% of the cases and that patients with a rapid progression and/or greater than 80% stenosis are at high risk. From this point of view a carotid endarterectomy should be considered in order to prevent an occlusion of the ICA and a high risk of stroke.     

Management of carotid coils during routine carotid endarterectomy

BACKGROUND: A coil in the internal carotid artery (ICA), defined as a circular configuration or exaggerated S shape of the ICA, is occasionally encountered during endarterectomy for carotid bifurcation lesions. The significance of coils as an etiology for symptoms is difficult to determine. It is thought, however, that the failure to correct coils and kinks during routine carotid endarterectomy (CE) may lead to turbulence and failure of the CE. Various techniques have been discussed to repair coils. METHODS: Our technique consisted of complete dissection of the coil, routine use of a Javid shunt, standard endarterectomy, resection of the redundant ICA, re-approximation of the posterior wall of the ICA and patch angioplasty of the anterior wall. Three hundred and fifteen patients underwent CE between August, 1998 and February, 2000. Fifteen patients (4.7%) had a carotid coil that was repaired. There were ten men and five women. Mean age was 72.6+/-6.1 years. Ten patients had an asymptomatic stenosis. Four patients had lateralizing symptoms and one patient had dizziness. Fifteen patients underwent preoperative duplex scanning and 14 of these patients had MRA scans performed. All patients had a preoperative stenosis of 80-99% by duplex on the operated side. The right carotid artery was repaired in 12 patients. The left in three patients. The length of resected artery varied from 1.2-2.8 cm (1.93+/-0.49 cm). RESULTS: All patients survived surgery. One patient developed a cerebellar stroke on the third postoperative day. A postoperative carotid duplex scan demonstrated a widely patent repair. There were no cranial nerve injuries in this series. One patient died seven months after surgery from cardiac events with no follow-up duplex exam. There have been no long term strokes or anastomotic complications. Follow-up duplex scans demonstrated widely patent repairs (1-15% stenosis) in seven patients and low end 15-49% stenosis in five patients. CONCLUSIONS: Resection of redundant ICA with re-anastomosis of the posterior wall and patch reconstruction of the anterior wall gives acceptable perioperative and long term results.     

Carotid Artery Stump Pressure (CASP) in 1135 consecutive endarterectomies under general anesthesia: an old method that survived the test of times

AIM: Intraoperative electroencephalography, somato-sensory evoked potentials and transcranial Doppler have been proposed to replace carotid artery stump pressure measurement (CASP) as the test of choice in the evaluation of cerebral tolerance during temporary carotid occlusion. CASP is a simple, inexpensive test that does not require an additional specialist in the operating room. Herein, we attempt to demonstrate that CASP is a reliable test that does not need to be replaced by more sophisticated and expensive techniques. METHODS: Over the last 6 years, 1 135 consecutive carotid endarterectomies (CEA) were performed under general anesthesia at our institution. There were 592 males and 429 female patients with an age range of 39 to 95 years (mean 72 +/- 9 years). Hypertension, diabetes, smoking, coronary artery disease and chronic renal insufficiency were present in 71%, 39%, 36%, 32% and 26%, respectively. Internal carotid artery (ICA) stenosis ? 70% was confirmed by duplex scanning in 92% of the cases. The remaining 8% of cases had 50% to 69% ICA stenosis in neurologically symptomatic patients. Asymptomatic patients accounted for 75% of the cases. Contralateral ICA occlusion was observed in 57 cases (5%). Indwelling shunts were used when CASP was < 45 mmHg. Carotid patches were used in 233 cases. Completion duplex scanning was performed in all cases. CASP was measured by inserting a 23-gauge needle into the common carotid artery (CCA) after clamping the ICA to avert possible embolization during needle insertion. Once the tip of the needle was confirmed intraluminally by pressure measurement and triphasic waveform tracing, the CCA and the external carotid artery were clamped. After a flat line tracing was depicted on the monitor, ICA clamp was released and CASP was recorded. RESULTS: CASP was < 45 mmHg in 233 cases (21%) (Group I) and > or = 45 mmHg in 902 cases (79%) (Group II). The mean CASP in presence of contralateral ICA occlusions was 40 +/- 15 mmHg while it was 65 +/- 27 mmHg for patent contralateral ICAs (P < 0.0001). The overall 30-day stroke rate was 1% (1 135 cases). It was 3% (7/233) for group I and 0.5% (4/902) for group II (P < 0.01). In patients with postoperative strokes CASP ranged from 23 to 44 mmHg (mean 33 +/- 8) in group I (shunted) and it varied from 59 to 116 mmHg (mean 99 +/- 28) in group II (non-shunted) with P < 0.001. The causes of stroke in group I were hyperperfusion (2), partial ICA thrombosis (2), embolization (2) and worsening of acute stroke (1). In group II there were 2 cases of embolization and 2 of ICA thrombosis. No patient had a stroke caused by decreased intraoperative global cerebral perfusion. The overall 30-day mortality rate was 0.5%. The overall combined stroke/death rate was 1.5%. CONCLUSION: CASP > or = 45 mmHg was a reliable predictor of adequate cerebral perfusion during 1,135 consecutive CEAs performed under general anesthesia. The percentage of indwelling shunts utilized in this series was not significantly different from the ones using more expensive and sophisticated techniques.     

A rational algorithm for duplex scan surveillance after carotid endarterectomy.

PURPOSE: This study was undertaken to determine the appropriate timing and frequency of duplex ultrasound scanning after carotid endarterectomy (CEA) for the detection of high-grade stenosis caused by recurrent carotid stenosis or contralateral atherosclerotic disease progression. METHODS: In 221 patients who underwent 242 CEAs, duplex scanning was performed before, during, and after operation (in 3-month to 6-month intervals). High-grade internal carotid artery (ICA) stenosis (peak systolic velocity, >300 cm/s; diastolic velocity, >125 cm/s; ICA/common carotid artery ratio, >4) prompted the recommendation for repair. An average of four postoperative scanning procedures was performed during a mean follow-up period of 27.4 months. RESULTS: Intraoperative duplex scan results prompted the immediate revision of 12 repairs (4.9%), and one perioperative stroke (<1%) occurred. Six CEAs (2.7%) had asymptomatic recurrent stenosis (>50% diameter-reduction [DR]; systolic velocity, >125 cm/s) develop. Only one of six patients had >75% DR stenosis develop and underwent reoperation (<1% yield for CEA surveillance). The yield of surveillance of the unoperated ICA was higher (P =.003), and 12% of unoperated sides had progressive stenosis (n = 21) or occlusion (n = 3) develop, which led to seven CEAs for high-grade stenosis. Disease progression to >75% DR stenosis was five times as frequent (P =.002) in patients with >50% DR stenosis initially. All patients but one who required contralateral endarterectomy for disease progression had >50% ICA stenosis when first seen. During the follow-up period, no disabling strokes ipsilateral to an operated carotid artery occurred, but three strokes occurred in the hemisphere of the contralateral unoperated ICA. CONCLUSION: The yield of duplex scan surveillance after CEA was low. Only 13 patients (5.9%) had severe disease develop to warrant additional intervention. Progression of contralateral disease rather than restenosis was the most common abnormality that was identified. Duplex scanning at 1-year to 2-year intervals after CEA is adequate when a technically precise repair is achieved and minimal contralateral disease (<50% DR) is present. A policy of duplex scan surveillance and reoperation for high-grade stenosis was associated with a 1.6% incidence rate of disabling stroke during the follow-up period.     

Timing and frequency of perioperative carotid color-flow duplex scanning: A preliminary report

PURPOSE: The results of intraoperative and early postoperative carotid color-flow duplex scanning (CFS) after endarterectomy were reviewed to determine whether any perioperative studies could be eliminated. METHODS: Patients undergoing carotid endarterectomy with intraoperative CFS between 1986 and 1997 were identified. Early postoperative CFS was performed between 1 day and 3 weeks postoperatively, then it was performed again at 6 months postoperatively. RESULTS: During the study period, 560 patients, 325 men and 235 women, underwent 621 carotid endarterectomies. A satisfactory intraoperative carotid CFS was completed in 611 (98.4%) patients. There were 20 (3.2%) vessels with a major defect that required revision for fronds or flaps (n = 11), retained atheroma (n = 5), low flow (n = 2), high velocity or turbulence (n = 1), or dissection (n = 1). Another 146 vessels (23.5%) had minor defects, such as retained proximal atheromas or small (less than 3 mm) fronds, but were not revised. The remaining 445 vessels were normal. The first postoperative CFS was normal in all the revised carotids and in 138 (94.5%) vessels with minor intraoperative defects. At 6 months, recurrent stenosis (more than 75% area reduction) was identified in 1 of 18 revised carotids (5.5%), 4 of 138 vessels (2. 9%) with minor defects, and 17 of 406 vessels (4.2%) that were normal intraoperatively. The incidence of recurrent stenosis was not significantly different in the three groups (P =.7). CONCLUSION: Intraoperative CFS is useful because major unsuspected defects can be corrected immediately, thus avoiding potential neurologic morbidity. However, the postoperative day 1 CFS can be eliminated in most cases, because it does not provide any relevant clinical information.     

Screening for asymptomatic internal carotid artery stenosis: Duplex criteria for discriminating 60% to 99% stenosis

Purpose: The Asymptomatic Carotid Atherosclerosis Study (ACAS) showed that carotid endarterectomy reduces stroke risk in symptom-free patients with 60% or greater internal carotid artery (ICA) stenosis. This will surely lead to the performance of an increased number of screening duplex examinations. Assuming that positive study results will lead to arteriography or endarterectomy and keeping in mind the modest benefit for prophylactic endarterectomy demonstrated by ACAS (absolute risk reduction for ipsilateral stroke of 5.8% at 5 years), duplex criteria for 60% or greater ICA stenosis must have high positive predictive values (PPV). Determining criteria for 60% or greater stenosis, which emphasized high accuracy and PPV, forms the basis for this study.Methods: Stenoses detected by angiography in 352 ICAs were blindly compared with those detected by duplex scanning. Duplex criteria were determined for highest overall accuracy in detection of 60% or greater ICA stenosis and for 95% or greater PPV.Results: Maximal accuracy for detection of 60% or greater stenosis was 90%. This was achieved by the combination of a peak systolic velocity of 260 cm/sec or greater and an end diastolic velocity of 70 cm/sec or greater (sensitivity 84%, specificity 94%, PPV 92%). The 95% PPV for 60% or greater stenosis results from combining peak systolic velocity of 290 cm/sec or greater and end diastolic velocity of 80 cm/sec or greater.Conclusions: With use of these criteria duplex scanning accurately detects with high PPVs the threshold level of ICA stenosis defined in ACAS as receiving stroke reduction benefit from prophylactic carotid endarterectomy. These criteria should be useful for carotid artery screening and minimizing unneeded intervention. (J VASC SURG 1995;21:989-94.)     

Irradiation-induced extracranial carotid stenosis in patients with head and neck malignancies

BACKGROUND: Carotid stenosis is a recognized complication of external irradiation to the head and neck for malignancy. This study aim to investigate the pattern and prevalence of radiation induced carotid disease, and to identify risk factors associated with significant stenosis. METHODS: In a comparative cross-sectional study, carotid arteries color flow duplex scan was performed on 240 patients who had received external irradiation to the head and neck area, with a mean interval of 72 months from radiotherapy. They consisted of 181 men and 59 women, with a mean age of 59 years. Fifteen patients had a history of cerebrovascular symptoms. RESULTS: Internal carotid artery (ICA) stenosis of 70% or greater was detected in 29 arteries in 24 patients. Common carotid artery (CCA) disease of > or =70% was present in 13 arteries in 12 patients. Overall 28 patients had significant ICA/ CCA disease (11.7%). Patients with nasopharyngeal and laryngeal carcinoma had more cerebrovascular symptoms, and more frequent CCA stenosis. Significant ICA/CCA stenosis was associated with age, smoking, coronary heart disease, stroke, no head and neck surgery, time interval from radiotherapy, and the site of primary tumor. On logistic regression analysis age (>60 years), cerebrovascular symptoms, interval from irradiation (>5 years), and nasopharynx and larynx cancer were found to be independent significant (P<0.05) predictors of 70% or greater ICA/CCA stenosis. CONCLUSIONS: Patients who had received radiotherapy to the head and neck have a high risk of developing significant carotid stenosis. Routine duplex ultrasound screening in these patients is indicated.     

New duplex ultrasound scan criteria for managing symptomatic 50% or greater carotid stenosis

PURPOSE: The North American Symptomatic Carotid Endarterectomy Trial (NASCET) showed that selected patients benefited from surgery when their carotid artery was 50% or more stenosed. This study assessed the accuracy of color-flow duplex ultrasound scanning (DUS) parameters to detect 50% or greater carotid artery stenosis and to determine the situations in which carotid endarterectomy (CEA) without angiography could be justified. METHODS: From March 1, 1995, to December 1, 1995, all patients considered for CEA were studied with DUS and carotid angiography. Results of the two tests were blindly compared. DUS measurements of internal carotid artery (ICA) peak systolic velocity (PSV), end diastolic velocity, and ratio of the ICA to common carotid artery PSV (ICA/CCA) were subjected to receiver operator characteristic curve analysis to determine the most accurate criterion predicting 50% or greater angiographic stenosis. The criterion for identifying patients for CEA without angiography was selected from criteria with a high positive predictive value (PPV) and sensitivity. RESULTS: A total of 188 carotid bifurcations were available for comparison. A PSV (ICA/CCA) of 2 or higher was the most accurate criterion for detection of 50% or greater stenosis, with an accuracy rate of 93% (sensitivity, 96%; specificity, 89%; PPV, 92%). A PSV (ICA/CCA) of 3.6 or higher was the best criterion for identifying candidates for CEA who had not undergone earlier angiography, with PPV, sensitivity, specificity, and accuracy rates of 98%, 77%, 98%, and 86%, respectively. CONCLUSION: These redefined criteria detect the NASCET-defined threshold level of 50% or greater ICA stenosis, above which CEA results in stroke reduction. A management algorithm based on these criteria should help to minimize both angiography and unnecessary intervention.     

颈动脉外翻内膜剥脱术治疗颈动脉硬化狭窄

目的观察颈动脉外翻内膜剥脱术治疗颈动脉狭窄的疗效。方法24例颈动脉硬化狭窄患者,其中18例有慢性或一过性脑缺血症状,6例无症状;术前均行彩色超声、数字减影动脉造影(DSA)或CT和MRA扫描检查,颈动脉狭窄程度65％～95％;在颈丛麻醉下行颈动脉外翻内膜剥脱术,手术要点是于颈动脉分叉处斜形切断颈内动脉,外翻颈内动脉剥除有粥样斑块的内膜,同时从颈总动脉切口剥除颈总动脉和颈外动脉增厚的内膜。结果全组无手术死亡,术后随访3～20个月,临床症状均有不同程度改善,一过性脑缺血症状消失,4例仍有轻度慢性脑缺血症状。术后行脑部多普勒超声检查,22例脑部供血有明显改善。结论颈动脉外翻内膜剥脱术是一种安全、有效和合理的手术方式。     

The Influence of Routine Completion Arteriography on Outcome following Carotid Endarterectomy

n = 69) normal; Group B (n= 29), abnormal, severe defects; Group C (n= 56), abnormal, mild–moderate defect. RCA detected 32 defects in Group B: 10 internal carotid (ICA), seven endpoint flaps, two kinks, one dissection; 16 external carotid (ECA), 10 severe endpoint defects and six total occlusion; six common carotid (CCA), five irregular proximal shelfs, one web. Thirty of 32 defects were successfully repaired as confirmed by normal repeat RCA studies; one ECA defect was not repaired and the ICA dissection was irreparable. In Group C, 67 mild–moderate defects were identified, but not corrected. These included <30% stenosis in the ICA (12), ECA (18), CCA (24), and vein patch corrugation or irregularity (13). For the entire series the postoperative ICA occlusion rate was 2% (3/154), stroke rate 2.6% (4/154), and a subsequent >50% restenosis rate of 7% (11/154). The yield from routine carotid completion arteriograms was significant, with 19% of studies identifying a severe defect that required repair. Although the difference in stroke rates and restenosis between the different groups did not reach statistical significance, patients with normal intraoperative arteriograms initially or after correction of a significant RCA defect had no early carotid occlusion (p= 0.05, Fisher's exact test) compared to patients with residual RCA defects. All early carotid occlusions occurred in patients with unrepaired defects. We conclude that RCA is an important method of quality control after CEA and exerts a subtle, but real, reduction in postoperative complications.     

The fate of unrepaired minor technical defects detected by intraoperative ultrasonography during carotid endarterectomy

This report describes the natural history of unrepaired minor technical defects detected by intraoperative B-mode ultrasonography during carotid endarterectomy. Intraoperative ultrasonography was used to assess the technical adequacy of 80 carotid endarterectomies. Sixty-two arteries were normal on intraoperative ultrasound examination, whereas the remaining 18 arteries had a total of 21 minor residual technical defects. The 21 minor defects consisted of four internal carotid artery lesions, nine common carotid artery lesions, and eight external carotid artery lesions, 19 had 1 to 3 mm intimal flaps, and two had small stenoses. Sixteen of the 19 intimal flaps resolved before the first postoperative ultrasound study. These arteries had normal examination results, which indicated that these intimal flaps had healed. The two stenoses detected intraoperatively could not be detected by postoperative carotid duplex scanning at 1 month follow-up. No statistically significant relationship was found between the presence of a minor residual defect on intraoperative ultrasonography and the subsequent development of recurrent stenosis or occlusion in any of the arteries assessed. These data suggest that certain minor technical defects in the carotid artery that were detected by intraoperative ultrasonography are benign and may not require repeat exploration of the carotid artery for repair.     

Carotid endarterectomy and completion contact arteriography

Intraoperative angiography in carotid extracranial surgery demonstrates technical defects in 5% to 8% of patients. A simple and safe method of completion contact angiography (CCA) has been perfected by adapting dental x-ray equipment, small dental film cassettes, and a "shoe box" type of developing unit. The method is not technician dependent, requires only 5 ml of contrast medium, has a completion time of less than 5 minutes, and produces no measurable radiation to the operating team. CCA was performed with no complications in 40 patients undergoing carotid endarterectomy. Two unsuspected internal carotid artery defects (5%) were discovered: in one a stenosis was immediately repaired, and in the other small thrombi that were seen but not removed were probably the cause of a postoperative transient ischemic attack. Two complete occlusions and one prominent intimal flap in the external carotid artery were also identified. We believe that CCA after carotid surgery should be used routinely because it is safe and simple and reveals unsuspected operative defects that can be corrected immediately.