Endovascular Stents for Carotid Artery Occlusive Disease

Carotid artery stenting and endarterectomy surgery techniques: A 30‑year time‑lapse

Carotid endarterectomy or carotid artery stenting (CAS), are the most important axes in carotid artery interventional management. A bibliometric analysis permits an easier access to the current literature trends and information to design future studies. The aim of the present study was to identify the knowledge routes on CAS and examine the research front on the topic. The search was interpreted in Scopus, from 1994 to 2023, and included only original articles and reviews. The BibTex format was used to download all citation and bibliographic data. The present analysis was conducted in two parts, a descriptive one and a network extraction process. Between 1994 and 2023, 34,503 references and 7,758 authors were recorded. The annual growth rate was 21.64%. The CAVATAS trial was the most cited article. As regards word trends, since 2017, trans-carotid stenting, risk factors and plaque characteristics are highlighted. CAS remains an area of high interest with a publication growth rate of >20% per year. As numerous questions remain to be answered, the need to determine the role of CAS may drive further research.

Multivariable Analysis of Patients With Severe Persistent Postprocedural Hypotension After Carotid Artery Stenting

Purpose: To assess the incidence and predictors of severe, persistent postprocedural hypotension (PPH) after carotid artery stenting (CAS). Materials and Methods: A total of 146 patients (mean age 72.8 years; 104 men) who underwent 160 CAS procedures using a standardized protocol at 3 vascular centers were retrospectively analyzed. The primary endpoint was postprocedural hypotension, defined as a reduction in systolic blood pressure (SBP) >40 mm Hg from baseline or an SBP of <90 mm Hg sustained for >1 hour after CAS. Potential prognostic factors for postprocedural hypotension were identified and subjected to logistic regression analyses; outcomes are presented as the odds ratios (ORs) with 95% confidence intervals (CIs). Results: PPH developed in 36 (24.7%) patients after 37 (23.1%) CAS procedures. These patients had significantly longer intensive care unit and hospital stays than those who did not develop hypotension (p<0.001). PPH was associated with severe lesion calcification (OR 6.28, 95% CI 1.81 to 21.98, p=0.004) and contrast volume (OR 1.02, 95% CI 1.01 to 1.02, p<0.001). A 4-fold increase in the risk of PPH (OR 4.22, 95% CI 1.38 to 13.33, p=0.012) was found between the embolic protection device most associated with PPH (Angioguard) and the device least associated with PPH (Emboshield NAV6). A similar trend was also observed for the Precise vs Xact stents (OR 6, 95% CI 2.08 to 17.6, p=0.001). Bootstrapped multivariable modeling identified the Precise stent and contrast volume as significant predictors of persistent postprocedural hypotension. Further investigation of the contrast volume revealed associations with sex, severe calcification, arch type, previous coronary artery bypass surgery, and primary stenting, suggesting that the contrast volume reflects the complexity of the procedure. Conclusion: The complexity of the procedure and type of stent may play a role in the development of postprocedural hypotension after CAS.

History and Current Status of Endovascular Management for the Extracranial Carotid and Supra-Aortic Vessels

Few procedures in the history of medicine have been more controversial than carotid artery stenting (CAS) for the management of carotid artery occlusive disease. Introduced just as the randomized trials were establishing carotid endarterectomy as the gold standard for carotid interventions, CAS has finally reached the point in its development when dedicated stenting systems are being tested in randomized clinical trials. Assisted by the concomitant use of distal protection devices, CAS has shown equipoise with endarterectomy in terms of safety at 30 days. This review summarizes the completed and ongoing CAS trials and the applications of endovascular techniques in the supra-aortic vessels.

Angioplasty and Stenting of the Extracranial Carotid Arteries

Purpose:

To study the feasibility and safety of stent-supported angioplasty in the treatment of atherosclerotic stenoses of the extracranial carotid arteries.

Methods:

Carotid angioplasty was attempted in 174 arteries (163 patients: 126 males; mean age: 71 ± 10 years, range 47 to 93). Mean lesion length was 15.1 ± 4.1 mm, and mean percent stenosis was 83.8% ± 7.3% (reference diameter 5.8 ± 0.7 mm). The majority (106, 65%) were asymptomatic (51% of all patients had severe coronary disease, 32% had peripheral vascular diseases). Patients underwent independent neurological examination, computed tomography, duplex ultrasonography, and angiography preprocedurally, 24 hours after the procedure, and at 6-month follow-up intervals. Most (142, 82%) carotid arteries were treated without cerebral protection, but a protective triple coaxial catheter was used in 32 (18%) patients. Stents (primarily Palmaz and Wallstent) were deployed routinely in all cases; 18% were implanted without predilation.

Results:

Immediate technical success was 173 of 174 (99.4%) (1 access failure referred electively to surgery). Eight (4.6%) neurological complications occurred in the periprocedural period: 3 transient ischemic attacks, 2 minor strokes, and 3 major strokes (1 amaurosis and 2 hemiplegias). Two major complications developed despite cerebral protection. There were no deaths or myocardial infarctions and only 3 cervical access site hematomas. Over a mean 12.7 ± 9.2 month follow-up (range 1 to 36), no ipsilateral neurological complications have been seen. There were 4 (2.3%) restenoses (3 redilated, 1 treated medically) and 1 mild Palmaz stent compression, all found within the first 6 months. Primary and secondary patencies at 3 years are 96% and 99%, respectively.

Conclusions:

Angioplasty with routine stenting seems feasible and safe for treating certain types of carotid stenoses even in high-surgical risk patients; however, randomized trials are necessary before this treatment can be offered as an alternative to endarterectomy.

Carotid Stenting with Cerebral Protection: First Clinical Experience Using the PercuSurge GuardWire System

Purpose:

To study the feasibility and safety of carotid angioplasty and stenting using a new cerebral protection device that temporarily occludes the distal internal carotid artery (ICA).

Methods:

Forty-eight high-risk patients (39 men, mean age 69.1 ± 8 years, range 54 to 86) with 53 ICA stenoses underwent percutaneous angioplasty and stenting via the femoral approach under cerebral protection afforded by a 0.014-inch GuardWire balloon occlusion device. Mean stenosis was 82.1% ± 9.65% (range 70 to 96) and mean lesion length was 16.0 ± 7.5 mm (range 6 to 50). Thirty-three (62%) lesions were calcified, and 38 (72%) were ulcerated. Thirty-two (60%) of the lesions were asymptomatic. With the occlusion balloon inflated in the distal ICA, the lesion was dilated and stented. The area was cleaned by aspiration and flushed via an aspiration catheter advanced over the wire. Blood samples were collected from the external carotid artery (ECA) and analyzed to measure the size and number of particles collected. Computed tomography and neurological examinations were performed the day after the procedure.

Results:

Immediate technical success was achieved in all patients with the implantation of 38 Palmaz stents, 8 Expander stents, and 11 Wallstents. Carotid occlusion was well tolerated in all patients but 1 who had multiple, severe carotid lesions and poor collateralization. Mean cerebral flow occlusion time was 346 ± 153 seconds during predilation and 303 ± 143 seconds during stent placement. Total mean flow occlusion time was 542 ± 243 seconds. One immediate neurological complication (transient amaurosis) occurred in a patient who had an anastomosis between the external carotid (EC) and ICA territories. Debris was removed in all patients with a mean 0.8-mm diameter catheter.

Conclusion:

Cerebral protection with the GuardWire device is easy, safe, and effective in protecting the brain from cerebral embolism. Larger studies are warranted.

Neurological Monitoring during Carotid Artery Stenting: The Duck Squeezing Test

Purpose:

To examine the usefulness of a novel method for neurological monitoring during carotid artery stenting (CAS).

Methods:

The records of patients who underwent elective CAS between June 1996 and October 1998 were reviewed to identify those who had neurological changes during the procedure. We examined whether the neurological change had been detected by a change in the ability of the patient to respond to predetermined commands involving a small rubber duck placed in the contralateral hand.

Results:

Two hundred seventy patients (320 vessels) underwent monitoring using the Duck Squeezing Test; 10 suffered neurological events during the procedure. Four of these were transient and temporally related to balloon inflation. Another 6 were tentatively ascribed to distal embolism. All instances were accompanied by a change in the patient's ability to perform the Duck Squeezing Test, which allowed the identification of the abnormal clinical situation. In addition, there were 4 false-positive tests secondary to the patient accidentally dropping the rubber duck.

Conclusions:

The Duck Squeezing Test is a sensitive and specific method for monitoring patients during elective CAS. Its practical applicability is based on sound neurophysiological concepts, which underscore the clinical importance of the test.

Percutaneous Stenting of the Internal Carotid Artery: The European CAST I Study

Purpose:

To report the results of a multicenter safety trial of percutaneous carotid stenting performed by vascular surgeons.

Methods:

Symptomatic or asymptomatic patients ≥ 65 years of age with internal carotid artery (ICA) stenoses ≥ 70% and ≤ 2-cm long were eligible for enrollment. The procedures were performed in an operating room with the choice of anesthesia and the percutaneous access site at the discretion of the surgeon. Only Palmaz stents were used.

Results:

From January 1, 1996 to December 31, 1997, 99 patients (74 men, mean age 70 years, range 51 to 94) were enrolled in the study. More than half (57 of 99 patients) were asymptomatic. The direct cervical approach was used predominantly (97%). Three (3%) cases were converted to surgery for inability to access the artery or deploy the stent (technical success 97%). No perioperative death or myocardial infarction was reported. Six (6%) procedural complications included 1 reversible arterial spasm, 2 dissections, 1 cervical hematoma, and 2 residual stenoses. One neurological event reversed within 7 days(1% minor stroke rate) and 4 (4%) transient ischemic attacks resolved within 24 hours. One (1%) asymptomatic early occlusion occurred 2 days postoperatively. No neurological event was observed in the 1- to 24-month follow-up (mean 13 months). Two (2%) patients died of nonprocedurally related causes. No stent compression was seen, but 1 asymptomatic occlusion and 3 asymptomatic, non-flow-limiting restenoses (2 < 40%, 1 at 60%) were found within 1 year (3% restenosis rate on an intention-to-treat basis). Patency was 98% at 1 year.

Conclusions:

The results of this trial support the contention that carotid stenting of short ICA lesions can be performed with a low neurological complication rate.

Hypotension and Bradycardia after Elective Carotid Stenting: Frequency and Risk Factors

Purpose:

To investigate the frequency of and risk factors for hypotension and bradycardia in response to elective carotid stenting and their association with neurological complications.

Methods:

A retrospective analysis was conducted of 471 patients (321 men; median age 72 years, interquartile range 64–77) who underwent elective carotid artery stenting without cerebral protection for high-grade (>70%) symptomatic (n = 147) or asymptomatic (n=324) internal carotid artery stenosis at a single center. Frequency and potential risk factors for severe hypotension (systolic blood pressure <80 mmHg) or bradycardia (heart rate <50 bpm) were studied.

Results:

Thirty-four (7%) patients had severe hypotension (n=23), bradycardia (n=2), or both (n=9) despite routine premedication with atropine and adequate fluid balance. Intravenous catecholamines (dopamine) were necessary in 8 patients with prolonged hypotension; none of the patients with bradycardia needed pacemaker support. Neurological complications (transient ischemic attack, minor stroke, major stroke, death) occurring in 33 (7%) patients were not significantly associated with hemodynamic instability (4/34 [12%] versus 29/437 [7%], p = 0.26). Age >77 years (fourth quartile; OR 6.40, 95% CI 1.80 to 22.78, p=0.004) and coronary artery disease (OR 2.81, 95% CI 1.29 to 6.14, p=0.010) were associated with an increased adjusted risk for hypotension or bradycardia.

Conclusions:

Hemodynamic instability due to hypotension and bradycardia in response to carotid artery stenting occurs in a relatively low proportion of patients. Elderly patients and those with coronary artery disease are at highest risk. Although the rate of neurological complications was not significantly increased in patients with hemodynamic instability, the higher frequencies of neurological complications in these patients admonish us to be careful.

Influence of Age upon Complications of Carotid Artery Stenting

Purpose:

To examine the impact of age upon the development of neurological and major systemic complications during or after carotid artery stenting.

Methods:

We reviewed the complications that occurred in patients undergoing elective carotid stent implantation between September 1994 and August 1996. The study population was then divided into 3 groups according to age: ≥ 80 (group A), 75 to 79 (group B), and ≤ 74 (group C) years. The rates of death, major and minor stroke, and myocardial infarction were compared among the groups, as well as with the rates reported by the major carotid endarterectomy (CEA) trials.

Results:

During the study period, 182 patients (216 vessels) were treated with carotid stenting. There were 19 (10.4%) complications: 1 (0.5%) death, 2 (1.1%) major strokes, 15 (8.2%) minor strokes, and 1 (0.5%) myocardial infarction. Neurological complications were clearly related to increased age with rates of 25.0% in group A versus 8.6% in group C (p = 0.042). The overall per patient rate of death or major stroke was 1.6% (1.4% per vessel).

Conclusions:

Increasing age has a negative impact on the rate of complications in carotid stent patients. However, the majority of those complications are minor. The relative roles of medical therapy, stenting, and CEA in patients > 80 years of age must await the results of randomized trials.

Intraventricular Hemorrhage after Carotid Stenting

Purpose:

To report an important complication related to carotid stenting.

Methods and Results:

A 71-year-old man with symptomatic subtotal occlusion of the left internal carotid artery had a 30-mm lesion treated percutaneously with implantation of 2 stents. Although the procedure was completed satisfactorily, left intraventricular hemorrhage occurred 4 hours later, possibly related to hyperperfusion injury. The patient expired 30 days after the stent procedure. Preoperative single-photon emission computed tomography revealed severely reduced vasoreactivity in the affected territory after acetazolamide challenge.

Conclusions:

The risk of hyperperfusion injury must be considered and minimized in patients with significant restriction of regional vasoreactivity. We recommend that cerebral hemodynamic status be determined prior to carotid stenting.

Outpatient Carotid Artery Stenting: A Case Report

Purpose:

To report a case of carotid artery stenting for asymptomatic carotid restenosis performed in an outpatient setting.

Methods and Results:

A 68-year-old man with right carotid restenosis after repeat carotid endarterectomy underwent carotid angioplasty and stenting on an ambulatory basis. The procedure to implant a Smart stent required 45 minutes; the femoral access site was closed with a puncture closure device. The patient experienced no sequelae to this procedure and is well 6 months after treatment.

Conclusions:

Outpatient delivery of percutaneous carotid stenting may be feasible in appropriately selected patients.

The Role of Carotid Duplex Ultrasound in Evaluating Plaque Morphology: Potential Use in Selecting Patients for Carotid Stenting

Purpose:

To study the role of duplex ultrasonography in evaluating plaque morphology and its correlation to neurological symptoms and cerebral infarctions on computed tomographic scans.

Methods:

The hospital records of 181 patients (107 males; average age 66 years, range 41 to 89) with > 50% carotid stenosis (29 bilateral lesions) who had undergone duplex ultrasonography, carotid arteriography, and cerebral computed tomography were studied retrospectively. Of 210 duplex examinations, 139 were appropriate for morphological analysis of surface characteristics and echogenicity.

Results:

Over half of the plaques examined had irregular surfaces (81, 58%) and displayed mixed (i.e., heterogeneous) echogenic patterns (74, 53%). Irregular (68 of 81, 84%) and heterogeneous (65 of 74, 88%) plaques were associated with ipsilateral neurological symptoms (p < 0.0001). Similarly, 44 (54%) of 81 irregular plaques and 42 (57%) of 74 heterogeneous plaques were found in patients with cerebral infarctions in the carotid territory (p < 0.0001).

Conclusions:

Heterogeneous and/or irregular plaques were more often associated with both neurological symptoms and infarctions than smooth or homogeneous plaques. These findings may have implications in patient selection for endoluminal therapy.

Carotid Plaque Characterization Using Digital Image Processing and its Potential in Future Studies of Carotid Endarterectomy and Angioplasty

Purpose:

To corroborate the validity of a computerized methodology for evaluating carotid lesions at risk for stroke based on plaque echogenicity.

Methods:

The records of 96 carotid endarterectomy patients (59 men; median age 69.5 years, range 52 to 83) with stenoses > 50% were studied retrospectively. Forty-one patients (43%) had been symptomatic preoperatively. All patients had undergone computed tomography (CT) to detect infarction in the carotid territory and a duplex scan to measure carotid stenosis. Plaque echogenicity was analyzed by computer, expressing the echodensity in terms of the gray scale median (GSM). The incidence of CT-documented cerebral infarction was analyzed in relation to symptomatology, percent stenosis, and echodensity.

Results:

Symptoms correlated well with CT evidence of brain infarction: 32% of symptomatic patients had a positive CT scan versus 16% for asymptomatic plaques (p = 0.076). The mean GSM value was 56 ± 14 for plaques associated with negative CT scans and 38 ± 13 for plaques from patients with positive scans (p < 0.0001). However, there was no difference in the GSM value between plaques with > or < 70% stenosis. Furthermore, the incidence of CT infarction was 40% in the cerebral territory of carotid plaques with a GSM value < 50 and only 9% in those with a GSM > 50 (p < 0.001).

Conclusions:

Computerized analysis of plaque echogenicity appears to provide clinically useful data that correlates with the incidence of cerebral infarction and symptoms. This method of analyzing plaque echolucency could be used as a screening tool for carotid stent studies to identify high-risk lesions better suited to conventional surgical treatment.

Stenting Treatment for Intra- and Extra-Cranial Atherosclerotic Diseases

The purpose of this study was to investigate the effect, safety and short-term outcome of stenting treatment for extra- and intra-cranial atherosclerotic diseases. Forty-one patients underwent stenting treatment using coronary and biliary stents.

Eleven patients had tubular or diffuse high-grade stenoses not amenable to standard balloon angioplasty involving intra-cranial arteries, while in thirty, extra-cranial arteries were involved. Stents were successfully implanted in 36 out of 41 lesions (88%) with 2% (1/41) of overall procedural morbidity rate. Procedural and clinical success rate of intra-cranial stent placement was 64% (7/11) and no complications occurred during or after intra-cranial stent placement: the morbidity rate was 0%. Hyperperfusion injury occurred in two patients after successful implantation of stents in subtotal occlusion of the internal carotid artery, and consequently the overall clinical success rate was 80% (33/41).

Restenosis occurred in four (12%) out of 33 patients who underwent six month follow-up arteriography. No ischemic attacks or stent-deformation occurred during follow-up after stenting treatment. For lesions not amenable to standard balloon angioplasty, endovascular stent placement seems to be a safe and effective treatment of modality.

Treatment of ruptured ICA during transsphenoidal surgery. Two different endovascular strategies in two cases

Rupture of the internal carotid artery (ICA) during transsphenoidal surgery is a rare but potentially lethal complication. Direct surgical repair of the ICA may be difficult and time-consuming in an acute setting. Urgent endovascular treatments with vascular plug or stent-graft have been the feasible options to date. We desrcibe two cases of iatrogenic rupture of ICA during transsphenoidal surgery. In the first case we occluded the ICA with a vascular plug at the site of tear where cross circulation was adequate. In the second case we had to preserve the ICA with stent-graft since there was no adequate cross circulation. These two strategies are discussed below.

Cerebral protection devices for use during carotid artery angioplasty with stenting: A health technology assessment

Objectives:This study sought to examine the safety, efficacy, and economic implications of the use of cerebral protection devices during carotid artery angioplasty and stenting (CAS) in high-risk patients with severe carotid artery disease (CAD).

Methods:A comprehensive search for peer- and non–peer-reviewed studies that compared carotid endarterectomy (CEA) or CAS without cerebral protection to CAS with cerebral protection and appeared in the English language literature between January 1990 and January 2005 was completed. Information from studies identified was extracted using a common data abstraction form and then critically appraised against published quality assessment criteria.

Results:Of the eight studies found, six provided information on technical or procedural success rates, with values ranging from 95.6 percent to 100 percent. Three of the four studies comparing groups of patients who received CAS with cerebral protection with those who received only CAS reported a non-statistically significantly higher 30-day incidence of death and stroke (major or minor) in the latter group. None of the three studies comparing CAS with cerebral protection to CEA demonstrated a statistically significant difference in the 30-day incidence of death, major stroke, or myocardial infarction between treatment groups. No economic analyses were found.

Conclusions:In high-risk patients with severe CAD, the evidence suggests that CAS with cerebral protection may offer a safe and efficacious alternative to CEA, reducing the risk of embolic peri-procedural complications associated with CAS to acceptable levels.

A comparison of balloon-mounted and self-expanding stents in the carotid arteries: immediate and long-term results of more than 500 patients

PURPOSE

To compare the rates of neurological complications and restenosis for balloon-mounted (BM) versus self-expanding (SE) stents deployed in the extracranial carotid arteries.

METHODS

Among 513 patients (312 men; mean age 71.3 years, range 27-91) who underwent carotid artery stent placement, 496 received 520 stents. The patients were followed with periodic duplex ultrasound examinations; angiography was performed whenever the duplex scan identified a >50% stenosis or symptoms warranted investigation. Periprocedural data on complications were analyzed on an intention-to-treat basis, while intermediate-term neurological complications were compared in stented patients.

RESULTS

In the periprocedural period, there were 19 (3.7%) transient ischemic attacks, 10 (1.9%) minor strokes, 6 (1.2%) major strokes, and 8 (1.6%) deaths among the 513 patients. Five (1.0%) of the deaths were related to neurological complications (3.9% all stroke/neurological death rate). Among the 496 patients receiving 247 (48%) BM stents and 273 (52%) SE stents in 518 arteries, the all stroke/neurological death rates were 3.6% and 4.0%, respectively (p>0.05). During a mean follow-up of 20.6 months (range to 5.6 years), the 3-year freedom from all fatal and ipsilateral nonfatal strokes excluding the 30-day periprocedural period was 95.0% for BM stents and 95.2% for SE devices. Vessel patency (>50%) at 3 years was 92.0% in the population: 96.3% for BM stents and 83.7% for SE stents (p=0.0422).

CONCLUSIONS

The rate of neurological complications following carotid stenting has been relatively low overall, and no differences were found relative to the type of stent deployed. Vessel patency was excellent at 3 years, with slightly better patency in BM stents, but because of their vulnerability to compression, they will not replace SE stents.

Evaluation of glycoprotein IIb/IIIa inhibitors in carotid angioplasty and stenting

PURPOSE

To review the immediate neurological and bleeding complications associated with the use of glycoprotein (GP) IIb/IIIa inhibitors in patients undergoing extracranial carotid artery stent placement.

METHODS

A retrospective review was performed of 550 patients (321 men; mean age 71.1 years, range 28-91) who underwent carotid artery angioplasty and stent placement. Glycoprotein IIb/IIIa inhibitors were given prophylactically along with heparin to 216 patients, whose outcomes were compared to a control group of 334 patients who received intravenous heparin alone. Primary endpoints were the immediate and 30-day neurological complications, including transient ischemic attacks (TIAs), minor and major strokes, and neurologically-related deaths. The secondary endpoint was any abnormal bleeding.

RESULTS

The all stroke/neurological death rate in 216 patients treated with heparin and GP IIb/IIIa inhibitors was 6.0% (13 events) compared 2.4% (8 events) in the 334 patients in the heparin-only control group (p=0.0430). Two of the 4 neurologically-related deaths in the GP IIb/IIIa inhibitor group resulted from intracranial hemorrhages; there were no intracranial hemorrhages in the heparin-only group. There was 1 episode of extracranial bleeding in the GP IIb/IIIa inhibitor group treated with embolization. The incidences of significant puncture-site bleeding requiring transfusion were similar in the groups.

CONCLUSIONS

Neurological complications following percutaneous carotid artery interventions have been relatively few. The neurological sequelae in carotid stent patients receiving glycoprotein IIb/IIIa inhibitors were more numerous and consequential, which suggests that the use of GP IIb/IIIa inhibitors in carotid stenting should be discouraged.

Unprotected carotid artery stenting compared to carotid endarterectomy in a community setting

PURPOSE

To evaluate the feasibility and safety of carotid artery stenting (CAS) performed by a dedicated multidisciplinary team in a community hospital.

METHODS

Forty-nine patients (30 men; mean age 74.3 +/- 7.4 years, range 51-88) with 14 symptomatic and 35 asymptomatic >50% carotid stenoses were enrolled into the study and treated with self-expanding stents without cerebral protection. The patients were evaluated at 30 days for death, neurological sequelae, and length of stay. A contemporaneous group of 140 patients (80 men; mean age 72.3 +/- 7.7 years, range 43-89) undergoing carotid endarterectomy (CEA) was used for comparison of the outcome measures. Owing to crossover of failed CAS patients to the CEA group, the data were analyzed according to intention-to-treat and treatment-received.

RESULTS

The only difference in baseline characteristics between the treatment and control groups was the greater frequency of bilateral disease in the CEA group (p=0.009). The CAS procedures were successful in 47 (96.0%) patients; 2 access failures were converted to endarterectomy, and 1 access-site pseudoaneurysm was treated surgically. There were no deaths or myocardial infarctions in either group. In the CAS group, there were no major and only 2 (4.1%) minor strokes compared to 4 (2.9%) major and 4 (2.9%) minor strokes in the CEA group (p>0.05). Median LOS was significantly lower in the CAS group (p<0.0001).

CONCLUSIONS

Careful case selection and multidisciplinary collaboration facilitate the safe performance of carotid stenting in a community setting with acceptable early results.

Carotid Stent-Assisted Angioplasty: The Newest Addition to the Surgeons' Armamentarium in the Management of Carotid Occlusive Disease

Carotid artery angioplasty and stenting (CAS) has been accomplished in multiple centers with short-term and midterm results similar to carotid endarterectomy (CEA). Until completion of multicentered prospective evaluation of the benefit of CAS versus established therapy (CEA) clinical judgment must be used to determine whether an individual patient with unusual technical challenges and/or risks might be best suited for CEA or CAS. We report our experience with 41 CAS procedures in 39 patients treated from November 1996 through November 2001. Six patients had primary lesions (three symptomatic and three asymptomatic). Thirty-three patients had 35 procedures for recurrent carotid stenosis (11 symptomatic and 24 asymptomatic). Technical success was achieved in 40 of 41 procedures. No deaths occurred. The 30-day major stroke rate was one in 41 (2.4%), and the overall 30-day stroke/transient ischemic attack rate was three in 41 (7.3%). No recurrence or late neurologic events were seen in patients treated for primary carotid stenosis. A 23 per cent recurrence rate was observed in patients treated for recurrent carotid stenosis, after one or more CEAs, with mean follow-up of 18 ± 14 months. Recurrence requiring operative correction with carotid resection and interposition grafts occurred in three patients treated with CAS in this group. Late deaths occurred in six patients; one of these was due to stroke. Overall freedom from late stroke and/or need for reintervention (by Kaplan-Meier analysis) was 64 ± 13 per cent at 48 months in the group treated by CAS for post-CEA recurrence. CAS represents a technically simplistic means of providing carotid revascularization. However, its role remains undefined and benefits unproven. Surgical revascularization remains appropriate for patients with operable carotid lesions. However, surgical revascularization is not always an ideal option when we are faced with difficult carotid lesions and risks. For this reason we advocate that all surgeons who intend to remain specialists in the management of carotid disease should attain, master, and maintain the skills necessary for CAS.

Carotid artery stenting in older patients: is age a risk factor for poor outcome?

PURPOSE

To assess the impact of age on technical success and complications of carotid stenting in a prospective single-center cohort study.

METHODS

One hundred eleven consecutive patients (74 men; median age 70 years) with >or=70% symptomatic (n=33) or >or=90% asymptomatic (n=78) internal carotid artery (ICA) stenosis underwent carotid artery stent implantation. Primary technical success and periprocedural complications were compared in patients aged >75 years (n=28) to patients <75 years (n=83).

RESULTS

Patient groups below and above 75 years compared well with respect to baseline demographic and clinical data. Successful stenting was achieved in 108 (97%) patients. The combined neurological complication rate was 7% (n=8), with 1 (1%) major stroke, 1 (1%) minor stroke, and no 30-day mortality. Technical angiographic complications occurred in 8 (7%) patients. No significant differences between patients >75 years and those <75 years were observed for primary success rates (100% [28/28] versus 96% [80/83]; p=0.8), overall complications (14% [4/28] versus 16% [13/83]; p=1.0), neurological complications (7% [2/28] versus 7% [6/83]; p=1.0), or technical complications (7% [2/28] versus 4% [3/83]; p=0.6).

CONCLUSIONS

Elective carotid stenting can be performed safely in older patients with several comorbidities. Patient age does not seem to be an independent risk factor for poor outcome after endovascular treatment of internal carotid artery stenosis.

Benefits of cerebral protection during carotid stenting with the PercuSurge GuardWire system: midterm results

PURPOSE

To examine the possible beneficial effect of a new cerebral protection device based on balloon occlusion of the distal internal carotid artery (ICA) and debris aspiration for patients undergoing carotid artery stenting (CAS).

METHODS

One hundred and eighty-four CAS procedures were attempted under cerebral protection using the PercuSurge GuardWire system in 167 patients (129 men; mean age 70.5 +/- 9.2 years, range 40-91)). The lesions were mainly atherosclerotic, and half (n = 93) were asymptomatic. Eighteen restenotic and 7 post-radiation stenoses were also treated.

RESULTS

Technical success was 99.5%. All lesions were stented except 3 postangioplasty restenoses. Prophylactic occlusion during balloon dilation and stenting was well tolerated in 176 (95.7%) patients. Microscopic analysis of the aspirated blood showed different types of particles numbering between 7 and 145 per procedure with a mean diameter of 250 microm (56-2652 microm). The 30-day stroke and death rate was 2.7%: 3 periprocedural complications at <48 hours (1 major stroke and 2 transient ischemic attacks), 1 intracerebral hemorrhage at 3 days, and 1 death of cardiac failure at 3 weeks.

CONCLUSIONS

This study yielded a favorably low rate of periprocedural embolic events comparable with standard CAS series. Protection devices may play an important role in future carotid interventions and expand the applicability of the procedure. Randomized studies (surgery versus CAS with and without cerebral protection) are awaited.

Carotid artery stenting: effect of learning curve and intermediate-term morphological outcome

PURPOSE

To assess the impact of learning on the rate of success and complications of carotid stenting in a single-center, one-operator series and prospectively follow a patient cohort with regard to restenosis.

METHODS

In 303 patients (mean age 70 +/- 8.8 years), 320 internal carotid arteries (ICA) were treated with carotid stenting for stenoses > or = 70%. Four groups of 80 consecutive interventions were compared with regard to primary technical success and periprocedural complications. Stent patency in follow-up was assessed using duplex scanning.

RESULTS

Stenting was successful in 298 (93%) arteries. The combined neurological complications (transient ischemic attacks and all strokes) and 30-day death rate was 8.2% (n = 25), but the all stroke and 30-day death rate was 3.0% (n = 9). A significant reduction in the frequency of neurological complications after the initial 80 interventions was observed (p = 0.03), but technical success was not appreciably improved with increasing experience thereafter. Over a median 12 months (interquartile range 6 to 24), cumulative patency rates were 91%, 90%, and 91% at 6, 12, and 36 months, respectively.

CONCLUSIONS

Elective carotid stenting can be performed with excellent technical success, an acceptable frequency of periprocedural complications, and good intermediate-term patency. However, our findings suggest that a larger number of interventions should be performed to overcome the negative effects of the initial learning phase.

Management of neurological complications of carotid artery stenting

PURPOSE

To review the neurological complications associated with extracranial carotid artery stenting and to preliminarily assess techniques used to manage these complications.

METHODS

Between April 1994 and August 2000, 450 patients (270 men; mean age 70.2 years, range 27-89) had stents implanted to treat 472 cervical carotid artery stenoses. Over half (257, 57%) of the patients were symptomatic. A variety of stents were implanted percutaneously after predilation of the lesion; a third of the patients received glycoprotein IIb/ IIIa inhibitors intraprocedurally in addition to a standard oral antiplatelet regimen (aspirin and ticlopidine or clopidogrel). Occurrence and management of neurological complications within the 30-day periprocedural period were reviewed.

RESULTS

There were 14 (3.1%) transient ischemic attacks (TIAs), 10 (2.2%) minor strokes, and 3 (0.7%) major strokes. Among 6 (1.3%) procedure-related deaths, 4 had neurological causes. The total stroke and death rate was 4.2% (n = 19). All the TIAs, 4 of which occurred between 1 and 14 days poststenting, were treated medically, as were the minor strokes, 3 of which occurred >24 hours after stenting. Only 2 minor stroke patients had mild residual upper extremity motor deficits. Intra-arterial thrombolytic therapy was administered in 5 cases (2 major strokes survivors and 3 patients who suffered a neurologically-related death); occlusions were identified in the proximal middle cerebral artery (MCA) in 3 and the distal MCA in 2. Angiographic improvement was noted in 4 (80%), but only the 2 (40%) with distal MCA occlusions did well clinically.

CONCLUSIONS

Neurological complications following carotid artery stenting are inevitable. The occurrence of minor strokes >24 hours following stenting may indicate a possible late embolic phenomenon, which warrants investigation. Likewise, the marginal efficacy of intra-arterial thrombolytic therapy demonstrates an inability to lyse embolic plaque and underscores the need for effective distal protection.

Carotid artery stenting in patients with high-risk anatomy for carotid endarterectomy

PURPOSE

To report the results of carotid artery stenting (CAS) in patients considered to have high-risk anatomical characteristics for carotid endarterectomy.

METHODS

CAS was performed in 39 carotid arteries of 37 consecutive patients (26 men; mean age 72 +/- 8 years, range 56-88) who met the criteria for high-risk surgical anatomy: previous ipsilateral carotid endarterectomy (20/39, 51.3%), common carotid bifurcation above the mandibular angle (5/39, 12.8%), contralateral carotid artery occlusion (15/39, 38.5%), or previous radiation therapy to the neck (1/39, 2.6%). Palmaz, Integra, or Wallstents were deployed via a percutaneous femoral artery access. Independent neurological evaluation was performed at specified time points, and a dedicated committee adjudicated all clinical events.

RESULTS

Procedural success was 100%, with no major in-hospital complications. Neurological events were rare. Only 1 (2.6%) transient ischemic attack occurred prior to discharge; at 30 days, 1 (2.6%) additional minor stroke had been observed, giving a 2.6% cumulative 30-day "death plus any stroke" rate. Over a mean 11 +/- 6-month follow-up, 2 (5.4%) patients died of nonneurological causes, but there were no strokes.

CONCLUSIONS

CAS is a viable endovascular revascularization technique that can be performed safely and effectively in patients with high-risk anatomy for carotid endarterectomy.

The ICAROS registry of carotid artery stenting. Imaging in Carotid Angioplasties and Risk of Stroke

ICAROS (Imaging in Carotid Angioplasties and Risk Of Stroke) is a multicenter international registry of carotid artery stenting designed to determine the criteria for identifying patients at higher or lower risk of periprocedural stroke and restenosis at 1 year. The aim of the registry is to improve patient selection and consequently reduce the risk of cerebral embolization during carotid stenting. The registry is open to all interventionists performing carotid stenting, and the participants are free to apply their own endovascular techniques and devices, including cerebral protection mechanisms. All cerebral ischemic events following the procedure will be reported. Follow-up surveillance to 1 year will include periodic duplex scanning and neurological examinations. Echographic plaque images will be standardized for comparison, processed for echodensity, and analyzed by computer at the Registry Center. Correlation will be investigated between the echographic index (gray-scale median) and the risk of embolism and outcome of carotid stenting.

An endovascular model of carotid stenosis for the evaluation of thrombolysis and angioplasty

PURPOSE

To develop a porcine carotid artery thrombosis model using a novel stent-graft device to evaluate the efficacy of thrombolytic therapy and angioplasty procedures.

METHODS

An endovascular device made from a tapered polytetrafluoroethylene graft inverted in a self-expanding nitinol stent was delivered to bilateral carotid arteries via a right femoral approach in 16 pigs. Carotid thrombotic occlusion ensued from flow stasis created by the intrastent stenosis. Via selective carotid catheterization from a femoral approach, urokinase (250,000 IU) was pulse-sprayed in one carotid artery while a control saline solution was infused in the contralateral vessel; delivery times were 1 hour, 8 hours, 3 days, or 6 days after carotid occlusion (4 animals per time period). After thrombolysis, balloon angioplasty was performed to maintain carotid patency. Arteriography and intravascular ultrasound were used to evaluate the efficacy of thrombolysis. Light microscopy was used for histological analysis of the thrombus.

RESULTS

Carotid artery occlusion occurred in 15+/-8 minutes after stent-graft placement in all animals. Urokinase was effective in recanalizing all occluded arteries in the 1-hour, 4-hour, and 3-day groups (100%) but was effective in only 2 of 4 animals in the 6-day group (p < 0.05). Overall thrombolytic efficacy was 78%+/-7%. Control saline solution showed no thrombolytic effect (p < 0.001). Angioplasty successfully restored normal luminal diameter in all fully lysed arteries (100%). Histological analysis showed fibrin-predominant thrombus with a varying degree of platelet deposition.

CONCLUSIONS

This endovascular approach, which creates a carotid stenosis using this novel stent-graft device, is reliable in producing carotid thrombosis. In our model, thrombolytic therapy was effective in restoring luminal patency, and the intraluminal stenosis is amenable to balloon angioplasty. The model is useful for the evaluation of antithrombotic therapy and adjunctive endovascular interventions.

Safety, efficacy, and durability of carotid artery stenting for restenosis following carotid endarterectomy: a multicenter study

PURPOSE

To present the results of a multicenter registry established to collect data on carotid stent procedures in patients with restenosis following carotid endarterectomy.

METHODS

The procedural details, outcomes, and late follow-up results were collected from 14 centers in the United States. Thirty-day and late stroke and death rates were analyzed.

RESULTS

Three hundred and thirty-eight patients (201 men; 71 +/- 8 years) underwent carotid stenting in 358 arteries. The average duration from carotid endarterectomy was 5.5 +/- 7.3 years. Sixty-one percent of the patients were asymptomatic. The overall 30-day stroke and death rate was 3.7%. The minor stroke rate was 1.7% (6/358), and the major nonfatal stroke rate was 0.8% (3/358). The fatal stroke rate was 0.3% (1/358), and the nonstroke-related death rate was 0.9% (3/338). There was 1 (0.3%) fatal and 1 (0.3%) nonfatal stroke during the follow-up period. The overall 3-year rate of freedom from all fatal and nonfatal strokes was 96% +/- 1% (+/- SE).

CONCLUSIONS

Carotid artery stenting can be performed in patients with restenosis following carotid endarterectomy with 30-day complication rates comparable to those of most published studies on repeat carotid endarterectomy. Results of late follow-up suggest that this technique is durable and efficacious.

Stent-graft treatment of a common carotid artery pseudoaneurysm

PURPOSE

To report a case demonstrating successful endovascular treatment of a right common carotid artery pseudoaneurysm using a commercially prepared balloon-expandable covered stent.

METHODS AND RESULTS

A 50-year-old man was evaluated for syncopal episodes. He had a history of severe trauma sustained in a motor vehicle accident 3 years before symptom onset. Doppler ultrasound scanning detected a pseudoaneurysm at the origin of the right common carotid artery. The defect measured 25 mm x 20 mm with a 22-mm-long neck on angiography and computed tomography; there was no evidence of carotid stenosis or associated vascular pathology. Via a percutaneous femoral access, 2 Jostent peripheral stent-grafts were placed at the level of the aneurysm, safely achieving complete repair of the arterial wall defect. The patient was asymptomatic at his 12-month evaluation. Color flow duplex scans showed continued exclusion of the pseudoaneurysm.

CONCLUSIONS

Wide-necked aneurysms in the extracranial carotid arteries may be treated with stent-grafts, which can achieve complete and permanent reconstruction of the arterial wall by excluding the aneurysm.

Symptomatic subtotal occlusion of the innominate artery treated with balloon angioplasty and stenting

PURPOSE

To report the endovascular treatment of a subtotal occlusion of the innominate artery giving rise to subclavian steal syndrome.

METHODS AND RESULTS

A 60-year-old man in general good health was admitted to the hospital for sudden onset of amaurosis in the right eye. Thrombosis of the central retinal artery was diagnosed. Physical examination, color flow duplex imaging, and aortic arch angiography showed a subtotal occlusion of the innominate artery with right subclavian steal syndrome. One month later, balloon dilation and stenting of the innominate artery was performed through a right axillary access without cerebral protection. The innominate artery was recanalized with correction of the steal syndrome and restoration of the right radial pulse; no complications occurred. Twelve months later, color flow duplex sonography confirmed innominate stent patency and antegrade flow in the right vertebral artery.

CONCLUSIONS

Our experience supports the view that percutaneous endovascular techniques are appropriate and are the preferred treatment for lesions of the supra-aortic vessels. Continued surveillance will determine their long-term durability.

Carotid stenting for severe radiation-induced extracranial carotid artery occlusive disease

PURPOSE

To present our experience with carotid artery stenting as an alternative treatment to endarterectomy in patients with radiation-induced carotid artery occlusive disease.

METHODS AND RESULTS

Fourteen patients (10 males; mean age 61 years, range 52 to 79) underwent percutaneous stenting of 15 carotid arteries for severe radiation-induced extracranial stenoses. Technical success was achieved in all patients, with reduction of the mean stenosis from 77% +/- 6% to 8% +/- 2%. In 2 patients, ipsilateral vertebral artery lesions were stented concomitantly. One patient had a minor stroke after the procedure but recovered fully in 2 days. No other complications were encountered. Nine (64%) patients had 6-month follow-up imaging (angiography or duplex scanning) that showed no evidence of restenoses (obstruction > or = 50%). At 18 +/- 2 months, 3 (21%) patients had died from unrelated causes. No neurological events occurred, and no repeat carotid artery interventions were required in the remaining patients.

CONCLUSIONS

Carotid stenting is an effective treatment option for severe radiation-induced carotid artery occlusive disease.

Initial experiences of carotid stenting with palmaz stent

Results of cervical carotid stenting are reported. Twenty-nine lesions in 25 cases were treated by percutaneous transluminal balloon angioplasty combined with stent placement. All the lesions were successfully dilated. There was one embolic complication during the operation that caused deterioration of preoperative symptoms. Stent deformation causing more than 30% luminal narrowing occurred in one case. Instent restenosis with more than 50% luminal narrowing was seen in bilateral lesions in one case. These were satisfactory results as an initial experience, but further improvement in this technique is considered essential especially to avoid embolic complications.