Carotid Endarterectomy: The Gold Standard

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.

Operative Repair for Aortic Aneurysms: The Gold Standard

Surgical treatment of abdominal aortic aneurysm (AAA) is being challenged by newer, minimally invasive therapies. Such new treatment strategies will need to prove themselves against concurrent results of standard operative AAA repair, within defined medical risk and aneurysm morphological categories. We review the natural history of AAAs, the medical risk levels for elective AAA repair, aneurysm morphology and its impact on operative mortality, the issue of high-risk patient treatment, and the current standard of care for AAAs based on single-center, multicenter, and population-based statistics. In good-risk patients, aneurysms > 5 cm in diameter are best treated by replacement with a prosthetic graft. Operative mortality should be < 5% and 1-year survival > 90%. Aortic endograft techniques must meet or exceed these standards if they are to supplant standard surgical repair.

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.

Endovascular Stents for Carotid Artery Occlusive Disease

Purpose:

To study the feasibility and safety of endovascular stenting of cervical carotid artery stenosis.

Methods:

Between April 1994 and May 1997, 108 consecutive patients (58 men; mean age 70.1 years) with ≥ 70% carotid stenosis were treated with percutaneous stent implantation under a protocol that featured independent neurological review. Forty-four percent were asymptomatic. Over half the lesions (59%) were in the internal carotid artery; the mean stenosis was 86%. Palmaz stents were implanted without cerebral protection following preliminary balloon dilation; two Wallstents were used in long lesions.

Results:

Carotid stents were successfully placed in 108 of 114 (95%) lesions. Of the 6 technical failures, 5 were access related and 1 was due to seizures during balloon dilation. Two major (1.8%) and 2 minor (1.8%) strokes occurred (3.7% stroke rate for 108 patients; 3.5% in 114 procedures), all in symptomatic patients, one of whom died. There were 5 (4.4%) transient ischemic attacks and 2 (1.8%) brief seizure episodes during dilation. One patient died of a cardiac event on day 20. The all stroke or death rate was 5.3% based on 114 arteries at risk (5.6% in 108 patients). In the mean 6-month follow-up (range 1 to 36) of 97 eligible patients, 3 (3.1%) died from unrelated causes. There was 1 restenosis (1.0%) from a stent compression, which was successfully redilated. There were no neurological sequelae, cranial palsies, or cases of stent or vessel thrombosis in follow-up.

Conclusions:

The use of stents in the treatment of cervical carotid occlusive disease appears feasible, effective in the short term, and without excessive risk of periprocedural stroke.

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.

Carotid Revascularization Using Endarterectomy or Stenting Systems (CARESS): Phase I Clinical Trial

Purpose:

To determine whether carotid stenting with embolic protection is equivalent to carotid endarterectomy (CEA) in a broad risk population of patients with symptomatic and asymptomatic carotid stenosis.

Methods:

A prospective, multicenter Phase I trial was conducted comparing standard CEA to carotid stenting systems (CSS) in patients with symptomatic (≥50%) and asymptomatic (≥75%) carotid stenosis. Patients were enrolled using selection criteria reflective of broad clinical practice. The enrollment ratio at each clinical site was designed to be 2:1 (CEA to CSS) to achieve a planned enrollment of 450 patients: 300 in the CEA arm and 150 in the CSS cohort, which would ensure adequate precision with a coefficient of variation ≤0.35. The primary endpoint for comparison was 30-day all-cause mortality and nonfatal stroke.

Results:

Between April 2001 and December 2002, 14 clinical sites enrolled 439 patients, of which 397 (247 men; mean age 71 years, range 44–89) were treated: 254 with CEA and 143 patients with CSS (ratio 1.8 to 1.0). More than 90% of patients had >75% stenosis; ∼68% of patients were asymptomatic. There were no significant differences in baseline patient characteristics between the treatment groups with the exception of a more frequent history of prior CEA (30% CSS versus 11% for CEA, p<0.0001) and prior carotid stent placement in the CSS group (6% versus 0% for CEA, p = 0.0002). There was no significant difference in the 30-day combined all-cause mortality and stroke rate by Kaplan-Meier estimate between CEA (2%) and CSS (2%). There was no significant difference in the secondary endpoint of combined 30-day all-cause mortality, stroke, and myocardial infarction between CEA (3%) and CSS (2%).

Conclusions:

This study suggests that the 30-day risk of stroke or death following carotid stenting with cerebral protection is equivalent to standard carotid endarterectomy in a broad risk population of patients with carotid stenosis.

Anesthesia for Carotid Stent Procedures

Purpose:

To present the techniques of anesthesia management used during percutaneous carotid interventions involving balloon dilation and stent deployment.

Methods and Results:

Two access routes may be used for carotid angioplasty, and the anesthesia techniques for each are different. In the conventional common femoral artery approach, the patient is sedated, heparinized, and ventilated by mask with 100% oxygen; the groin site is anesthetized locally with lidocaine. When the procedure reaches the point of balloon inflation, the patient is awakened, and atropine is administered to block the baroreceptor response. The heparin is not reversed after the procedure. General anesthesia with short-acting nonopioid intravenous anesthetics is preferred for patients undergoing direct puncture of the common carotid artery. The patient is intubated and ventilated with 100% oxygen. Here the patient is awakened after completion of the procedure, at which time protamine sulfate is used if needed to restore coagulation time to normal prior to sheath removal. The anesthesiologist must be vigilant in monitoring hemodynamic and neurological status throughout these carotid interventions, particularly during balloon inflations and after the sheath removal for the cervical approach.

Conclusions:

Anesthesia for percutaneous carotid interventions differs from that used for carotid surgery. Protection of the brain from ischemic insult is paramount, and scrupulous attention to physiological factors influencing cerebral blood flow is mandatory. The anesthesiologist plays a crucial role in maintaining hemodynamic stability, adjusting anticoagulation, and monitoring neurological status.

Stenting in the Carotid Artery: Initial Experience in 110 Patients

Purpose:

To evaluate the feasibility, safety, and efficacy of intravascular stents in the treatment of extracranial carotid artery occlusive disease.

Methods:

According to protocol, stent therapy was offered to symptomatic patients with ≥ 70% arteriographically defined carotid stenoses or ulcerative lesions and, after September 1994, to asymptomatic patients with ≥ 75% stenoses. From April 1993 to September 1995, 110 nonconsecutive patients (79 males; mean age 72 years, range 45 to 85) consented to participate in the study. The majority (79 [72%]) were asymptomatic. Lesions meeting the treatment criteria were in the proximal common (n = 3); mid common (n = 12); distal common (n = 8); internal (ICA) (n = 92); and external (n = 2) carotid arteries. Seven patients had bilateral ICA stenoses, and 17 patients were treated for postsurgical recurrent disease. The mean lesion length and diameter stenosis for all lesions were 12.4 ± 9.2 mm and 86.5% ± 10.6%, respectively. The procedures were performed either via direct percutaneous access to the cervical common carotid artery or through a retrograde femoral artery approach. Standard balloon dilation preceded deployment of balloon-expandable stents in most cases. No postprocedural anticoagulation was used (aspirin only).

Results:

In 110 patients (117 arteries) intended for treatment, 109 (99.0%) (116 arteries [99.1%]) were successfully treated with 129 stents (128 Palmaz, 1 Wallstent). One percutaneous procedure failed (0.9%) for technical reasons (stent could not be deployed) and was converted to carotid endarterectomy. Minor complications included 4 cases of spasm (successfully treated with papaverine); 1 flow-limiting dissection (stented); and 6 access-site problems. There were 7 strokes (2 major, 5 reversible) (6.4%) and 5 minor transient events (4.5%) that resolved within 24 hours. Three patients were converted to endarterectomy (2.7%) prior to discharge; 1 stroke patient expired (0.9%), and another patient died of an unrelated cardiac event in hospital. In the 30-day postprocedural period, 2 ICA stents occluded (patients asymptomatic). Clinical success at 30 days (no technical failure, death, endarterectomy, stroke, or occlusion) was 89.1% (98/110). Over a mean 7.6-month follow-up (range 2 to 31), no new neurological symptoms developed. Another stent occlusion at 2 months and one case of flow-limiting intimal hyperplasia at 7 months were detected on routine duplex scanning in asymptomatic patients. Life-table analysis shows an 89% cumulative primary patency rate.

Conclusions:

Based on this early experience, carotid stenting appears feasible from a technical standpoint, with good midterm patency. However, the incidence of neurological sequelae is a serious problem. Technical enhancements and a more aggressive antiplatelet regimen may have a positive impact on these events.

Percutaneous Transluminal Angioplasty of Supra-aortic Vessels

Purpose:

To retrospectively review the techniques and results of percutaneous transluminal angioplasty (PTA) in the supra-aortic vessels.

Methods:

Over a 5-year period, 112 patients underwent percutaneous treatment of 151 lesions in the innominate, subclavian, carotid, and vertebral arteries. The percutaneous technique included standard retrograde femoral artery access in the majority of patients with balloon dilation of the lesion site. In the more recently treated patients, stents were deployed for suboptimal PTA; primary stent deployment was used rarely. Symptom resolution and > 50% increase in flow were criteria necessary for a successful procedure.

Results:

In this population, 141 (93%) of 151 lesions were successfully treated. PTA achieved 100% success in stenotic lesions in the internal (n = 9) and external (n = 2) carotid; common carotid (n = 8); subclavian (n = 67); and innominate (n = 13) arteries. Ninety-two percent (36/39) of vertebral artery stenoses were successfully treated. In 13 cases of subclavian occlusion, however, only 6 (46%) were recanalized. There were 3 periprocedural complications, but only 1 was major; a focal stroke manifesting as right arm weakness occurred in a patient with left common carotid PTA and stenting. Five cases of reocclusion have been seen in 5 years of follow-up. All occurred in the subclavian artery, and 3 of the 5 were in arteries originally occluded.

Conclusions:

Brachiocephalic PTA can achieve excellent immediate and long-term results in proximal stenoses. Subclavian occlusions do not respond well to PTA, and those successfully recanalized have a high restenosis rate (50%). PTA of the arch vessel branches, particularly the vertebral artery, should be attempted only by experienced interventionists. Atherosclerotic lesions in the internal carotid arteries are best treated with endarterectomy at present, but fibromuscular dysplasia in the carotid arteries is an appropriate indication for PTA therapy.

What Should We Do with Asymptomatic Carotid Stenosis?

The benefit of prophylactic carotid endarterectomy (CEA) for patients with asymptomatic severe carotid stenosis in the major randomised surgical studies was small, expensive and may now be absorbed by improvements in best practice medical intervention. Strategies to identify patients with high stroke risk are needed. If surgical intervention is to be considered the complication rates of individual surgeons should be available. Clinicians will differ in their interpretation of the same published data. Maintaining professional relationships with clinicians from different disciplines often involves compromise. As such, the management of a patient will, in part, depend on what kind of specialist the patient is referred to. The clinician's discussion with patients about this complex issue must be flexible to accommodate differing patient expectations. Ideally, patients prepared to undergo surgical procedures should be monitored in a trial setting or as part of an audited review process to increase our understanding of current practice outcomes.

Endovascular Treatment for Extracranial Carotid Stenosis

Introduction:

Bibliometric analysis is a quantitative method that can evaluate publications related to a specific topic.

Methods:

A PubMed database search was conducted from 2003 to 2012 using the search term “carotid” AND “stenos*” as a part of the title or abstract.

Results:

A total of 1590 articles were published in 329 different journals. A total of 751 (47.2%) publications were original articles, 1501 (94.4%) were written in English, 153 (9.6%) received funding, 584 (36.7%) were published by the United States, and 673 (42.3%) resulted from multidisciplinary collaboration. Of the original articles, 538 (71.6%) had retrospective design and 275 (36.6%) had sample size of <50. Vascular surgery departments produced the most articles (n = 339, 21.3%), followed by radiology (n = 270, 17.0%), cardiology (n = 260, 16.4%), neurosurgery (n = 198, 12.5%), and neurology (n = 196, 12.3%). Five major departments published only a small portion (5.1%-26.5%) of articles in their own specialty journals.

Conclusion:

The publication in journals across disciplines and multidisciplinary collaboration are 2 peculiar characteristics of research in this topic.

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.

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.