Disease progression in contralateral carotid artery is common after endarterectomy

OBJECTIVE: Although the North American Symptomatic Carotid Endarterectomy Trial (NASCET) and the Asymptomatic Carotid Atherosclerosis Study (ACAS) have helped to define the role of carotid endarterectomy (CEA) for both symptomatic and asymptomatic lesions, the role of surveillance of the contralateral carotid artery remains unclear. The purpose of this study was to determine the progression of contralateral carotid artery disease with serial duplex ultrasound scans after CEA compared with the recurrent stenosis rate for the carotid artery ipsilateral to the CEA. METHODS: From January 1990 to December 2000, 473 CEA procedures were performed at a Veterans Affairs Medical Center. From this group we identified 279 patients who had undergone first-time CEA, as well as preoperative duplex scanning and postoperative duplex scanning at least once, in the vascular laboratory. At each visit stenosis of the internal carotid artery (ICA) was categorized as none (0%-14%), mild (15%-49%), moderate (50%-79%), severe (80%-99%), or occluded. Analysis of probability of freedom from progression was determined. Progression was defined as an increase in ICA stenosis 50% or greater or increase to a higher category of stenosis if baseline was 50% or greater. The Cox proportional hazards model was used for data analysis. RESULTS: Mean patient age was 65.7 years (range, 33-100 years). The 1024 carotid duplex ultrasound scanning examinations performed (mean, 3.7; range, 2-13) included the last study done before the index CEA and all studies done after the CEA. Mean follow-up was 27 months (range, 1-137 months). Forty-six patients were found to have contralateral carotid occlusion at initial duplex scanning, and were therefore excluded from the contralateral progression analysis. Contralateral progression was more frequent than ipsilateral recurrent stenosis at long-term follow-up (P <.01). Annual rates of "any progression" and "progression to severe stenosis or occlusion" were 8.3% and 4.4%, respectively, for contralateral arteries, and 4.3% and 2.4%, respectively for ipsilateral arteries. As a result of surveillance, 43 contralateral CEAs (19% of initial cohort) were performed. Carotid stenosis regressed in 25 arteries (10.7%). Baseline clinical and demographic factors did not predict disease progression. Baseline contralateral stenosis did not predict time to "any progression," but was a strong predictor of "progression to severe stenosis or occlusion" (P <.001). CONCLUSIONS: After CEA, we identified an 8.3% annual rate of progression of contralateral carotid artery stenosis and a 4.4% annual rate of progression to severe stenosis or occlusion. Baseline contralateral stenosis was significantly predictive of progression to severe stenosis or occlusion. Clinical and demographic factors were not helpful in predicting which patients would have disease progression. These data may help in assessing the cost effectiveness of duplex scanning surveillance after CEA.     

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

OBJECTIVE: The best way to manage both symptomatic and asymptomatic severe carotid stenoses has been thoroughly demonstrated by large randomized clinical trials, but less is known about the natural history and management of the contralateral asymptomatic internal carotid artery (ICA). This prospective study was undertaken to determine whether disease progressed in the contralateral ICA of patients who had undergone carotid endarterectomy (CEA) and were followed up clinically and by duplex ultrasound (US) scan. METHODS: The contralateral asymptomatic ICAs of 599 patients who had undergone CEA for severe carotid disease over a 10-year period were followed up clinically and with duplex US scan at 1 month and then every 6 months. ICA stenosis was classified as mild (30%-49%), moderate (50%-69%), severe (70%-99%), or occlusion. Progression was defined as an increase in ICA stenosis of 50% or more for ICAs with a less than 50% baseline lesion or as an increase to a higher category if the baseline stenosis was 50% or more. End points of the study were the incidence of contralateral disease progression and late neurologic events. Kaplan-Meier analysis was used to estimate freedom from disease progression and from neurologic events. The relationship between progression and risk factors was also analyzed. RESULTS: Overall, disease progressed in 25.2% of patients (151/599) after a mean follow-up of 4.1 years. Disease progressed in 34.3% of patients (101/294) with mild stenosis vs 47.9% of patients with moderate stenosis (47/98; P = .016). Three additional patients with mild lesions at baseline progressed to severe lesions. The median time to progression was 29.8 months for mild and 18.5 months for moderate stenoses (P = .033). The rate of late neurologic events referable to the contralateral ICA was 3.2% (19/599) for the entire series and 4.8% (19/392) for patients with a 30% or greater ICA stenosis: these included 4 (0.7%) strokes and 15 (2.5%) transient ischemic attacks. All but 3 events (16.3%; 16/98) occurred in patients with disease progression from moderate to severe stenosis. Overall, 53 late CEAs were performed. CONCLUSIONS: This prospective analysis has shown that disease progression in contralateral asymptomatic ICAs after CEA is relatively common in patients with a diseased ICA at the baseline and strongly supports duplex US surveillance, approximately every 6 months, in patients with more than mild disease. A baseline lesion is significantly predictive of progression to severe stenosis, and progression from moderate to severe stenosis is strongly associated with neurologic clinical events. No demographic or clinical factor proved useful in identifying patients likely to experience disease progression.     

Outcome of moderate carotid artery stenosis in patients who are asymptomatic

Purpose: The incidence rate of disease progression and stroke after the diagnosis of a moderate (50% to 79%) carotid stenosis was determined by means of color-flow duplex scanning. Methods: During a 4-year period, 344 male veterans with moderate internal carotid artery stenoses, on one or both sides, were examined at regular intervals for a mean period of 25 months. Carotid color-flow scans were obtained semiannually. Clinical follow-up was performed to determine the incidence rate of amaurosis fugax, transient ischemic attacks, nonhemispheric symptoms, and strokes. Results: New neurologic symptoms developed in 75 patients (21.8%). Fifty-one (14.8%) had ipsilateral symptoms during follow-up: 18 amaurosis fugax (5.2%), 14 transient ischemic attacks (4%), 5 nonhemispheric symptoms (1.4%), and 14 strokes (4%). Twenty-four patients (6.9%) had contralateral symptoms: 20 strokes (5.8%) and 4 transient ischemic attacks (1.2%). Life-table analysis showed that the annual rate of ipsilateral neurologic events was 8.1%, and the annual rate of stroke was 2.1%. Seventy-five patients (22%) died in the follow-up period. Disease progression to 80% to 99% stenosis or occlusion occurred in 71 of 458 vessels (15.5%). The internal carotid arteries that showed evidence of disease progression had a significantly higher initial peak systolic velocity (251 vs 190 cm/s; P < .0001) and end diastolic velocity (74 vs 52 cm/s; P < 0.0001). Black patients and patients with ischemic heart disease were at a higher risk for disease progression. We could not identify any atherosclerotic risk factors that reliably predicted patients in whom future ipsilateral neurologic symptoms were more likely to develop. However, there was an increased risk of stroke associated with progression of disease. Conclusion: Patients who are asymptomatic and who have moderate carotid stenoses are at significant risk for neurologic symptoms and death, but have a relatively low incidence rate of ipsilateral events. The initial flow characteristics in the stenotic vessel are predictive of future disease progression, but they are not helpful in identifying patients in whom symptoms will develop. (J Vasc Surg 1999;29:217-27.)     

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.     

Carotid Duplex with Contralateral Disease: The Influence of Vertebral Artery Blood Flow

t -tests were used to assess significant changes within groups and independent t-tests were used to compare changes between groups. Sixty-seven patients had a normal VAS and 43 patients had an abnormal VAS. Patients with an abnormal VAS had significantly greater decreases in EDV after contralateral CEA. In the abnormal VAS group, there was a higher incidence (23.2% vs. 16.4%) of ipsilateral overestimation of stenosis by duplex and a greater incidence (20.9% vs. 10.4%) of postoperative decrease in stenosis following contralateral CEA than in the normal VAS group. Patients who underwent CEA for severe stenosis versus moderate stenosis had significant postoperative decreases in ipsilateral PSV, EDV, and ICA/CCA ratio. Severe contralateral stenosis patients with an abnormal VAS had a significant decrease in EDV compared to patients with a normal VAS. Vertebral artery blood flow contributes significantly to the ``hemodynamic effect' of carotid disease identified by duplex.     

The natural history of moderate (50% to 79%) internal carotid artery stenosis in symptomatic,nonhemispheric, and asymptomatic patients

Purpose: This study was undertaken to determine the incidence of disease progression of moderate (50% to 79%) internal carotid artery stenosis in patients with symptoms, patients with nonhemispheric symptoms, and symptom-free patients and to define the risk of development of new neurologic events in each group.Methods: Over a 6-year period, 272 patients with moderate internal carotid artery stenoses were monitored for a mean of 44 months with color-flow duplex scanning (CFS). At the time of the initial scan, 142 patients were symptom free, 87 had experienced transient ischemic attacks, amaurosis fugax, or mild strokes, and 43 had ill-defined nonhemispheric symptoms. The average number of follow-up scans was 2.4 per patient (range 1 to 11).Results: During follow-up, 23 (26%) of the patients with symptoms, 17 (40%) of the patients with nonhemispheric symptoms, and 30 (21%) of the symptom-free patients had development of additional neurologic symptoms. Life-table comparison of ipsilateral ischemic events showed a significantly (p = 0.03) higher cumulative rate in the symptomatic group (20%) than in the asymptomatic group (7%) at 2 years. Mean annual stroke rates were 6% and 2% in patients in the symptomatic and asymptomatic groups, respectively. None of the patients in the nonhemispheric group had a stroke within 4 years of the initial study. Disease progression occurred in 16% of the patients. In the asymptomatic group, ipsilateral stroke occurred more frequently (p = 0.0001) in patients with disease progression (25%) than in patients with stable lesions (1%). CFS detected disease progression in 19 (79%) of 24 patients before the artery occluded or stroke occurred. In patients with symptoms, stroke was more frequent (p = 0.02) in patients with six or more risk factors (29%) than in those with five or fewer risk factors (7%).Conclusion: Although the risk of stroke is less in patients with moderate stenosis than it is in patients with severely stenotic lesions, symptom-free patients with advancing disease and patients with symptoms and multiple risk factors are at increased risk for development of neurologic events. These findings support the use of CFS to monitor patients with carotid artery disease and suggest that a more aggressive surgical approach may be indicated in selected patients with moderate carotid artery stenosis. (J VASC SURG 1995;21:346-57.)     

Conservative management of residual and recurrent lesions after carotid endarterectomy: Long-term results

Purpose: To document the natural history of residual and recurrent carotid stenoses that are initially treated without surgery, and to identify risk factors for recurrent stenosis. Methods: Review of data from a prospective carotid database with clinical and duplex follow-up. Analysis of rate of restenosis and rate of late reoperation by life table. Risk factor analysis by χ² and LEE-DESU statistics. Results: Three hundred forty-eight patients were available for follow-up, with 12 residual lesions (3.7%) and 22 recurrent lesions (6.6%). Rate of recurrent stenosis by life table analysis was 8.7% and 13% at 3 and 5 years. Restenosis was associated with smoking (p = 0.04) and contralateral progression. Only 21% of patients were underwent an operation within 5 years (p = 0.007) of restenosis developing, but eventually 10 of 22 patients required reoperation at long-term follow-up, eight for symptoms and two for progressive proximal stenoses. The late stroke rate was increased in patients who had residual or recurrent lesions compared with those who had normal duplex study results (18% vs 6%; p = 0.16) and was related to the ipsilateral artery. Conclusions: Recurrent lesions that remain asymptomatic can be managed without operation with likelihood of success in the near term (5 years). However, these patients are at increased risk of late stroke, and almost half will eventually require operation. Therefore, in good-risk patients operation for asymptomatic restenoses should be considered. (J Vasc Surg 1997;26:963-72.)     

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.     

The natural history of superficial femoral artery stenoses

Since the natural history of specific superficial femoral artery stenoses is not known, we examined progression rates of superficial femoral artery stenoses in 45 lower extremities found when arteriograms were obtained of 38 patients for symptomatic atherosclerotic disease in the opposite leg or abdomen. These initial superficial femoral artery arteriograms were compared with later arteriograms in 25 limbs, duplex scans in 27 limbs, and both modalities in 7 limbs. After a mean interval of 37 months, most superficial femoral artery stenoses (72%) did not progress. However, 12 superficial femoral artery stenoses progressed (28%; mean follow-up, 37 months, including 7 that occluded (17%). Superficial femoral artery stenoses progressed among patients who complained of symptom progression at a rate faster than that among asymptomatic patients (15.6%/year vs 3%/year; p = 0.006). Superficial femoral artery lesions also progressed more rapidly among patients whose contralateral superficial femoral artery was occluded (10%/year vs 1.6%/year; p = 0.04). By multivariate regression analysis, symptom progression and smoking history were predictive of superficial femoral artery stenosis progression. In the seven patients whose superficial femoral artery stenoses progressed to occlusion, the average rate of stenosis progression was 12%/year (maximum predicted rate, 30% per year by 95% confidence limit). These results indicate that superficial femoral artery stenoses usually progress with synchronous symptomatic deterioration. Other than symptom progression, only cumulative smoking history and contralateral superficial femoral artery occlusion could be associated with superficial femoral artery stenosis progression in this small series.(ABSTRACT TRUNCATED AT 250 WORDS)     

Screening for carotid disease and surveillance for carotid restenosis

Duplex scanning is being used now to screen patients with suspected carotid artery disease, as the sole diagnostic test before carotid endarterectomy, and for follow-up surveillance after carotid surgery. Although the role of screening in patients with neurologic symptoms generally is accepted, noninvasive screening of asymptomatic patients remains controversial. The basic rationale for screening is to detect disease that can be treated to improve the patient's outcome. Although debate over the value of endarterectomy for asymptomatic carotid stenosis will continue, there is abundant evidence from natural history studies and clinical trials indicating that patients with asymptomatic high-grade (80% to 99% by duplex) stenoses can benefit from surgery if it can be performed with an acceptably low perioperative complication rate. Therefore, screening appears to be justified in patients with asymptomatic neck bruits and patients being evaluated for peripheral arterial or coronary artery disease. Those who are found to have moderate stenoses (50% to 79%) should be followed up at 6-month intervals to detect disease progression that may require surgery. Patients with less than 50% carotid stenoses can be followed up annually. Early restenosis is relatively common after carotid endarterectomy, occurring in about 20% of patients followed up with serial duplex scans, but it appears to have a benign natural history in the majority of patients. Reoperation is indicated only for symptomatic recurrent lesions and selected high-grade asymptomatic restenoses. An early postoperative surveillance examination is justified to provide a baseline study. The frequency of subsequent follow-up examinations will be determined by the status of the contralateral nonoperated carotid artery or the development of neurologic symptoms.     

Progression of asymptomatic carotid stenosis: A natural history study in 1004 patients

Purpose: The purpose of this study was to delineate the natural history of the progression of asymptomatic carotid stenosis. Methods: In a 10-year period, 1701 carotid arteries in 1004 patients who were asymptomatic were studied with serial duplex scans (mean follow-up period, 28 months; mean number of scans, 2.9/patient). At each visit, stenoses of the internal carotid artery (ICA) and the external carotid artery (ECA) were categorized as none (0 to 14%), mild (15% to 49%), moderate (50% to 79%), severe (80% to 99%), preocclusive, or occluded. Progression was defined as an increase in ICA stenosis to ≥50% for carotid arteries with a baseline of <50% or as an increase to a higher category of stenosis if the baseline stenosis was ≥50%. The Cox proportional hazards model was used for data analysis. Results: The risk of progression of ICA stenosis increased steadily with time (annualized risk of progression, 9.3%). With multivariate modeling, the four most important variables that affected the progression (P < .02) were baseline ipsilateral ICA stenosis ≥50% (relative risk [RR], 3.34), baseline ipsilateral ECA stenosis ≥50% (RR, 1.51), baseline contralateral ICA stenosis ≥50% (RR, 1.41), and systolic pressure more than 160 mm Hg (RR, 1.37). Ipsilateral neurologic ischemic events (stroke/transient ischemic attack) occurred in association with 14.0% of the carotid arteries that were studied. The progression of ICA stenosis correlated with these events (P < .001), but baseline ICA stenosis was not a significant predictor. Conclusion: In contrast to recently published studies, we found that the risk of progression of carotid stenosis is substantial and increases steadily with time. Baseline ICA stenosis was the most important predictor of the progression, but baseline ECA stenosis also was identified as an important independent predictor. Contralateral ICA stenosis and systolic hypertension were additional significant predictors. We found further that the progression of ICA stenosis correlated with ischemic neurologic events but not baseline stenosis. The data provide justification for the use of serial duplex scans to follow carotid stenosis and suggest that different follow-up intervals may be appropriate for different patient subgroups. (J Vasc Surg 1999;29:208-16.)     

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.     

Significance of the early postoperative duplex result in infrainguinal vein bypass surveillance.

BACKGROUND: Duplex surveillance of infrainguinal vein grafts may not be efficient. METHODS: Consecutive patients who had received infrainguinal vein grafts were enrolled in a duplex surveillance program. A first scan at 6 weeks after surgery categorized grafts into four groups: (a) low risk grafts, (b) mild flow disturbance, (c) intermediate stenosis and (d) critical stenosis. Disease progression was assessed over time. RESULTS: Of 364 grafts followed-up for a median of 23 months, 236 (65%) had no flow abnormality at 6-weeks, and had a 40-month cumulative patency rate of 82%. The remaining 128 (35%) grafts had a flow disturbance. Of 29 critical stenoses, 15 were repaired, 11 occluded and three did not change. Of 57 intermediate lesions, 32 progressed to critical, nine occluded, two were repaired and 14 did not change or improved. Of 42 mild lesions, 16 progressed to a higher grade, four occluded and 22 did not change or improved. There was no significant difference in graft patency between grafts with repaired stenoses and those without stenoses, but grafts with untreated critical stenoses were associated with lower patency (p<0.001). CONCLUSIONS: A duplex scan 6 weeks after operation can predict those patients who require continuing duplex surveillance.     

Combined carotid endarterectomy with transluminal angioplasty and primary stenting of the supra-aortic vessels

BACKGROUND: Carotid endarterectomy (CEA) is the standard of care for patients with high-grade carotid artery stenosis who are acceptable surgical candidates. Focal occlusive lesions of the origin of aortic arch vessels can be effectively and safely treated with balloon angioplasty and primary stenting. The purpose of this study was to retrospectively review results of carotid endarterectomy for high-grade carotid bifurcation stenosis combined with intraoperative retrograde transluminal angioplasty and primary stenting of a hemodynamically significant stenosis at the origin of a proximal ipsilateral aortic arch vessel. METHODS: Between October 1994 and August 1998, 592 patients underwent CEA. Six patients were found to have hemodynamically significant tandem lesions affecting one of the aortic arch vessels and the ipsilateral ICA for an overall incidence of 1%. Age ranged from 63 to 78 years (mean 74.7). Four of 6 (67%) patients had asymptomatic lesions, and 2 of 6 (33%) had symptoms of cerebral ischemia. Five patients had tandem lesions affecting the proximal left common carotid artery and the left ICA. One patient had a tandem lesion affecting the innominate artery and the right ICA. Carotid duplex imaging and arch and cerebral arteriography was performed in all six patients. Arteriography confirmed high-grade stenoses in both the ICA and ipsilateral proximal aortic arch vessel. The range of stenoses in the ICA was 70 to 95% (mean 80.8%) measured arteriographically. The range of stenoses at the origin of the aortic arch vessels was 75-90% (mean 79.2%). All six patients underwent combined retrograde transluminal balloon angioplasty and primary stenting of the ipsilateral CCA or innominate artery with temporary occlusion of the ICA for cerebral protection. The endovascular procedure was then followed with standard surgical endarterectomy using an inline shunt. RESULTS: All six procedures were successfully completed. There were no periprocedural strokes or other morbidities. Follow-up ranged from 6 to 43 months (mean 23.6) and showed no evidence of recurrent stenosis by carotid duplex imaging. No TIAs or strokes related to the surgically corrected lesions were noted during the follow-up period. One patient suffered a right hemispheric stroke secondary to a high-grade right carotid stenosis which occurred two months after her procedure surgically correcting tandem lesions on the opposite side. CONCLUSIONS: Carotid endarterectomy with balloon angioplasty and primary stenting of an ipsilateral hemodynamically significant aortic arch trunk vessel stenosis can be safely and successfully accomplished and avoids the need for an intra/extrathoracic bypass procedure.     

The Fate of the External Carotid Artery after Carotid Artery Stenting. A Follow-up Study with Duplex Ultrasonography

OBJECTIVE: To evaluate the long-term effect of carotid angioplasty and stenting (CAS) of the internal carotid artery (ICA) on the ipsilateral external carotid artery (ECA). SUBJECTS AND METHODS: We prospectively registered the pre- and post-interventional duplex scans obtained from 312 patients (mean age 70 years) who underwent CAS. Duplex scans were scheduled the day before CAS, 3 and 12 months post-procedurally and yearly thereafter, to study progression of obstructive disease in the ipsilateral ECA compared to the contralateral ECA. The duplex ultrasound criteria used to identify ECA stenosis >or=50% were Peak Systolic Velocities of >or=125 cm/s. RESULTS: Preprocedural evaluation of the ipsilateral ECA demonstrated >or=50% stenosis in 32.7% of cases vs 30% contralateral. Both ipsilateral and contralateral 3 (1%) ECA occlusions were noted. After stenting 5 (1.8%) occlusions were seen vs 1% contralateral. No additional ipsilateral occlusions and 2 additional contralateral occlusions were noted at extended follow-up. The prevalence of >or=50% stenosis of the ipsilateral ECA (Kaplan-Meier estimates) progressed from 49.1% at 3, to 56.4%, 64.7%, 78.2%, 72.3%, and 74% at 12, 24, 36, 48, and 60 months respectively. Contralateral prevalences were 31.3%, 37.7%, 41.7%, 43.1%, 46.0%, and 47.2% respectively (p<0.001). Progression of stenosis was more pronounced in 234 patients (75%) with overstenting of the carotid bifurcation (p=0.004). CONCLUSION: Our results show that significant progression of >or=50% stenosis in the ipsilateral ECA occurs after CAS. There was greater progression of disease in the ipsilateral compared with the contralateral ECA. Progression of disease in the ECA did not lead to the occurrence of occlusion during follow up.     

Duplex imaging of lower extremity bypasses, angioplasties, and stents

Duplex scan surveillance after lower extremity bypass and endovascular interventions can have a favorable impact on outcome. Its application during an arterial intervention to exclude technical or hemodynamic abnormalities and as part of a postoperative surveillance program to detect stenosis has been shown to improve patency. Results of duplex imaging can identify the arterial reconstruction at high risk of failure/thrombosis, which requires more intensive surveillance. Based on stenosis severity and anatomy, duplex scanning can suggest which repair technique (open surgery vs percutaneous balloon angioplasty [PTA]) is more appropriate. The use of duplex imaging during PTA of graft or peripheral artery stenoses (duplex-monitored balloon angioplasty) is recommended to verify normalization of velocity spectra, because this end point is associated with improved stenosis-free patency. A duplex surveillance program combined with correction of progressively stenotic lesions is recommended after lower limb bypass and PTA.     

Asymptomatic high-grade internal carotid artery stenosis: is stratification according to risk factors or duplex spectral analysis possible?

High-grade (80% to 99% diameter reduction) asymptomatic internal carotid artery stenoses are associated with an increased neurologic event rate (transient ischemic attack, stroke, asymptomatic internal carotid artery occlusion) compared to less severe asymptomatic lesions. However, many do remain free of associated events. To determine which are most dangerous, we compared risk factors and duplex scan results in two groups with asymptomatic high-grade internal carotid artery stenoses. Group A included 31 patients with 33 unoperated high-grade lesions that remained asymptomatic for at least 12 months (mean 30 months). Group B included 25 patients with 26 initially asymptomatic lesions that subsequently were associated with a neurologic event (mean time to event 7.4 months). The groups did not differ significantly in average age, sex, aspirin use, smoking, or prevalence of hypertension, diabetes, or cardiac disease. With respect to the index high-grade lesion, there was no difference in the frequency of a greater than 50% contralateral internal carotid artery stenosis or greater than 50% ipsilateral external carotid stenosis. However, on duplex scanning, high-grade stenoses with greater than 6.5 kHz end-diastolic frequencies were more frequently associated with an event than high-grade lesions with lower end-diastolic frequency (p = 0.0004). Similarly, seven of 23 lesions (30%) with end-diastolic frequency greater than 6.0 kHz were associated with subsequent internal carotid artery occlusion compared to only one of 29 (3.5%) with end-diastolic frequency less than or equal to 6.0 kHz (p = 0.025). Analysis of internal carotid artery end-diastolic frequency may help select a subgroup of patients with asymptomatic high-grade lesions who are at greatest risk for subsequent neurologic symptoms or ICA occlusion or both.     

The importance of routine surveillance of distal bypass grafts with duplex scanning: a study of 379 reversed vein grafts

To assess the utility of routine duplex surveillance, 379 infrainguinal reversed vein grafts performed at two independent teaching hospitals were prospectively entered into a surveillance protocol from March 1986 through August 1989. An average of 3.2 postoperative duplex graft flow velocity (GFV) measurements per graft was obtained during a mean follow-up interval of 21 1/2 months. Only 2.1% of 280 grafts with GFV measurements greater than 45 cm/sec failed within 6 months of a normal surveillance examination. GFV measurements less than 45 cm/sec in 99 grafts led to arteriography in 75 grafts, identifying 50 stenotic lesions in 48 bypasses (12.6% of series). Inflow lesions were present in 5%, outflow stenoses in 2%, and intrinsic graft stenoses in only 6% of bypasses. Only 29% of grafts identified as failing by duplex scan were associated with a reduction in ankle-brachial index of greater than 0.15. Secondary reconstructions were performed in 48 grafts based on detection of a reduced GFV measurement; all such reconstructions are patent after a mean follow-up of 5 months. Duplex surveillance is more reliable in identification of failing vein grafts than is determination of ankle-brachial index.     

The origin of infrainguinal vein graft stenosis: A prospective study based on duplex surveillance

Purpose: The purpose of this study was to determine the origin of vein graft lesions and their propensity for progression based on prospective duplex surveillance of 135 infrainguinal vein bypasses.Methods: One hundred sixteen greater saphenous, 13 spliced, five cephalic, and one superficial femoral vein grafts were evaluated by color duplex imaging at surgical procedure, 1 and 6 weeks, 3 and 6 months, and every 3 to 6 months thereafter. Duplex-identified lesions were graded by peak systolic velocity and velocity ratio criteria and were either followed or subjected to revision.Results: Early postoperative duplex surveillance allowed stratification of infrainguinal grafts into two subsets. Of 91 (67%) grafts with normal early scans (at 3 months), only two (2.2%) developed de novo stenoses (at 6 and 8 months) that required revision. Forty-four grafts with abnormal duplex scans had a focal flow abnormality (peak systolic velocity >150 cm/sec, velocity ratio >1.5) in the graft body ( n = 24) or anastomotic region ( n = 20). In 14 grafts the flow abnormality (mean peak systolic velocity = 217 cm/sec, velocity ratio = 2.3) normalized. Ten additional grafts exhibited a moderate, persistent graft stenosis (mean peak systolic velocity 248 cm/sec, velocity ratio = 3.3) that was not repaired. All 20 grafts with lesions that progressed to high-grade stenosis (mean peak systolic velocity = 362 cm/sec, velocity ratio = 7.2) and were revised had a residual flow abnormality confirmed at operation, or it appeared by 6 weeks. In the entire series six (4.4%) grafts failed during the mean 12-month follow-up interval (range 3 to 30 months), 4 with unrepaired defects and two after revision.Conclusions: Prospective duplex surveillance verified that de novo graft stenosis was uncommon (<2.2%) after reversed and in situ saphenous vein bypass grafting. Graft stenoses developed at sites of unrepaired defects or early appearing conduit abnormalities. An early appearing duplex focal flow abnormality warranted careful surveillance, because one half of such sites progressed to a high-grade stenosis. Grafts with normal early duplex scans exhibited a low incidence of stenosis development or occlusion, and thus less intense postoperative surveillance can be recommended. (J VASC SURG 1995;21:16-25.)     

The natural history of stenoses within lower limb arterial bypass grafts using a graft surveillance program

Graft surveillance aims to identify those grafts that are at risk of failure as intervention in a patent but failing graft results in improved long-term patency and limb salvage rates compared to rescue of an occluded graft. Controversy exists as to which types of graft benefit the most from surveillance and whether patient factors such as diabetes and smoking status have an effect on graft survival. Our aims were (1) to clarify the natural history of midterm graft failure as a consequence of myointimal hyperplasia and (2) to identify which patients and grafts are at a higher risk of failure and at what time points this is most prevalent. Serial vascular laboratory and clinical data of 212 infrainguinal lower limb grafts in 197 patients were analyzed. Follow-up within the surveillance program was by focused examination with color flow duplex ultrasound at 0, 1, 3, 6, 12, and 18 months with respect to surgery. Outcomes were correlated with retrospectively collected data regarding patient demographics, smoking status, concurrent medication, comorbidity, and operative factors such as distal target vessel and conduit. During the program, 21.6% of grafts occluded. Overall, 16% of grafts underwent a salvage procedure, 40.5% of which were carried out at the 6-month time point. There were 56.6% of occlusions preceded by a stenotic lesion. Primary occlusions accounted for 95.9% in the prosthetic group and 66.5% in the femorocrural group. As a group, vein grafts were more likely to develop a progressive stenosis prior to occlusion, with 58.3% in this group predated by a stenotic lesion. Fewer than 75% of stenoses were common and had a variable natural history, with over 40% resolving or failing to progress. Throughout the study period, 56.2% of grafts remained stenosis-free. Stenoses were more common at the proximal anastomosis in the vein graft cohort. There were low rates of significant stenoses within the prosthetic group. These lesions were more likely to occur at the distal anastomosis but were poor predictors of occlusion. Statin use postoperatively was protective against the development of significant stenosis and occlusions, particularly in the above-knee grafts (p = 0.03). Surprisingly, preoperative smoking status was predictive of neither occlusion nor development of significant stenosis. The presence of diabetes was not predictive of poor outcome. Our findings suggest that graft surveillance is a valid method for detecting the presence of significant stenoses in vein grafts at high risk of failure without intervention. Despite the intensive follow-up, the program failed to detect lesions prior to occlusion in a large percentage of prosthetic and femorocrural grafts, so perhaps this group is poorly served by graft surveillance.