Carotid stenting and angioplasty: a statement for healthcare professionals from the Councils on Cardiovascular Radiology, Stroke, Cardio-Thoracic and Vascular Surgery, Epidemiology and Prevention, and Clinical Cardiology, American Heart Association

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.

The external validity of MRI-defined vascular depression

OBJECTIVE

Multiple diagnostic criteria have been used to define vascular depression (VD). As a result, there are discrepancies in the clinical characteristics that have been established for the illness. The aim of this study was twofold. First, we used empirically established diagnostic criteria to determine the clinical characteristics of magnetic resonance imaging (MRI)-defined VD. Second, we assessed the agreement between a quantitative and qualitative method for identifying the illness.

METHOD

We examined the baseline clinical and neuropsychological profile of 38 patients from a larger, double-blind, randomized, 12-week clinical trial comparing nortriptyline with sertraline in depressed older adults. Ten patients met quantitative criteria for MRI-defined VD based on the highest quartile of deep white matter hyperintensity (DWMH) volume. Fourteen patients met qualitative criteria for MRI-defined VD based on a DWMH score of 2 or higher on the Fazekas' modified Coffey rating scale.

RESULTS

Age, gender, cumulative illness rating scale-geriatric (CIRS-G) score, two measures of psychomotor retardation [the psychomotor retardation item of the Hamilton Rating Scale for Depression (HRSD) as well as performance on the Purdue Pegboard], and performance on the Stroop Color/Word test (a measure of the response inhibition component of executive functioning) were significantly different between those with VD and non-VD.

CONCLUSIONS

Patients with VD have a distinct clinical and neuropsychological profile that is mostly consistent across different methods for identifying the illness. These findings support the notion that MRI-defined VD represents a unique and valid subtype of late-life depression.

National trends in carotid artery revascularization surgery

Object

Several randomized trials have emerged with conflicting data on the overall safety of carotid artery stenting (CAS) in comparison with carotid endarterectomy (CEA). The authors hypothesize that changes in national trends correspond to publication of randomized trials, including an increase in utilization of CAS after publication of trials favorable to CAS (for example, Carotid and Vertebral Artery Transluminal Angioplasty Study [CAVATAS] and Stenting and Angioplasty with Protection in Patients at High Risk for Endarterectomy [SAPPHIRE]) and decrease in utilization of CAS after publication of trials favorable to CEA (for example, Endarterectomy versus Stenting in Patients with Symptomatic Severe Carotid Stenosis [EVA3-S] and Stent-Supported Percutaneous Angioplasty of the Carotid Artery versus Endarterectomy [SPACE]).

Methods

The Nationwide Inpatient Sample was obtained for the years 1998–2008. Individual cases were isolated for principal diagnosis of unilateral or bilateral carotid artery stenosis or occlusion undergoing CEA or CAS. The percentage of CAS for all carotid revascularization procedures was calculated for each year. Perioperative inpatient morbidity, including stroke or death, were calculated and compared.

Results

The percentage of patients undergoing CAS increased yearly from the start of the observed period to the end, with the exception of a decrease in 2007. The peak utilization of CAS for carotid artery revascularization procedures was 15% of all cases in 2006. The stroke or death rate was consistent at 5% among all patients undergoing CEA for all years, while the incidence of stroke or death decreased among patients undergoing CAS from 9% in 1998 to 5% in 2008.

Conclusions

The practice of CAS in the US is expanding, from less than 3% of all carotid artery revascularization procedures to 13% in 2008. The utilization of CAS was seen to correlate with publication of randomized trials. Utilization nearly doubled in 2005 after publication of the CAS-favorable SAPPHIRE in 2004, and decreased by 22% after publication of the CEA-favorable EVA-3S and SPACE in 2007. With the publication of Carotid Revascularization Endarterectomy Versus Stenting Trial (CREST), the authors predict a resultant increase in the rate of CAS for carotid artery disease in the upcoming years.

Development of an intravascular laser treatment with an infrared free electron laser. Selective removal of cholesterol ester in carotid atheromatous plaques

SUMMARY

We have studied to develop an intravascular device with an infrared free electron laser (FEL) to treat occlusive carotid atherosclerotic lesions. In this study, we irradiated the FEL with a wavelength of 5.75 mum on surgical specimens of human atheromatous carotid plaques. After the irradiation on a cholesterol-ester-accumulated portion of the carotid plaques under proper conditions, a microscope transmission FTIR (Fourier Transform Infrared) spectroscopy showed that the peak of a tissue infrared absorption spectrum corresponding to the molecular vibration of cholesterol ester (5.75 mum) disappeared.Tissue damages associated with the irradiation were not histologically noted. This study demonstrated that irradiation of FEL can selectively remove cholesterol ester from the human atheromatous carotid plaques.

Combined treatment using CEA and CAS for carotid arterial stenosis

In this study we report our surgical results of CAS and CEA for carotid stenosis and suggest an appropriate treatment strategy for patients with high risks such as bilateral carotid stenosis or medical risk factors. From January 2001 to December 2005 we surgically treated 182 patients with carotid stenosis. Seventy-nine lesions were treated by CEA and 145 by CAS, respectively. Although CEA was considered the first choice for severe carotid stenosis, CAS was chosen for treatment when CEA was considered a higher risk for patients. Stenosis of carotid arteries was relieved in all cases after CEA or CAS. Surgical mortality of CEA was 1.1% (1/94). Surgical mortality of CAS was 0.7% (1/145). Carotid stenotic lesions can be treated with comparably low morbidity and mortality rates using CEA or/and CAS considering each characteristic of carotid stenosis of patients even with medically high risk or bilateral carotid stenosis.

Randomized clinical trials: How will results influence clinical practice in the management of symptomatic and asymptomatic extracranial carotid occlusive disease?

Evaluation of the efficacy of carotid endarterectomy and stenting requires careful consideration of clinical trial methodology as applied to the primary clinical end points of the specific trial. Although publication of observational data including registries is helpful in selecting options for further study, these reports are not considered replacements for the randomized clinical trial. This article reviews methodology and results of registries and randomized clinical trials. Pending publication of larger clinical trials on the management of symptomatic and asymptomatic carotid stenosis within the next 1 to 3 years, carotid endarterectomy remains the preferred technique for cerebral revascularization. The only exceptions to this recommendation come from higher risk categories of patients; however, their identification is frequently difficult and controversial.

Carotid Endarterectomy in Patients with Contralateral Carotid Artery Occlusion

The aim of this study was to evaluate the 30-day outcome of carotid endarterectomy in patients with contralateral carotid artery occlusion and compare it to that in patients with patent contralateral carotid artery. We compared 2,959 carotid endarterectomies performed in patients with patent contralateral internal carotid artery to 373 carotid endarterectomies performed in patients with occlusion of the contralateral carotid artery in the same institute between 1988 and 2004. Patient demographics, surgical and anesthesiological strategy, perioperative neurological and cardiac events, and deaths were compared. The patients were grouped and analyzed according to the presence or absence of symptoms and to their gender. No significant difference was shown in perioperative cardiological and neurological events and deaths in patients with contralateral carotid occlusion versus patients without contralateral carotid occlusion. Females had significant more neurological events than males, in both the asymptomatic (P < 0.001) and symptomatic (P = 0.02) groups. Concomitant occlusion of the contralateral carotid artery was not associated with increased risk of perioperative cardiological or neurological adverse events. However, female gender was associated with higher risk for adverse neurological events.

Carotid Stenting: Should it Replace Endarterectomy in Higher-Risk Patients?

Carotid artery stenting (CAS) has emerged as a useful and potentially less-invasive alternative to carotid endarterectomy (CEA) for treatment of extracranial carotid stenoses. It has been suggested that specific patient subgroups, including those with significant medical comorbidities, recurrent stenosis, anatomically inaccessible lesions, and a hostile neck, might benefit from CAS. The purpose of this report is to evaluate whether or not CAS should replace CEA in the treatment of the high-risk patient. Results from a recently published randomized clinical trial and several individual center and multicenter case analyses will be used in this review.

A comparison of carotid artery stenting with neuroprotection versus carotid endarterectomy under local anesthesia

BACKGROUND

Carotid endarterectomy (CEA) and carotid artery stenting (CAS) reduce the risk of stroke in patients with high-grade carotid artery stenosis. Despite the known impact of type of anesthesia on outcome after CEA, none of the current studies comparing CEA with CAS addresses the effect of anesthetic choice on perioperative events. In this study, we compare our results of distally protected CAS versus CEA under local anesthesia.

METHODS

Clinical data of 345 patients who underwent 372 procedures for carotid artery occlusive disease over a 36-month were retrospectively collected for this analysis. Distal embolic protection was used in CAS procedures. All procedures, both CEA (n = 221, 59%) and CAS (N = 152, 41%), were performed under local anesthesia. The primary outcome measure was aggregate 30-day major ipsilateral stroke and/or death. Follow-up serial Duplex ultrasound examinations were performed.

RESULTS

Both patient cohorts were similar in terms of demographic and risk factors, with the exception of a higher incidence of coronary artery disease in the CAS group (59% versus 30%, P <.05). The 30-day stroke and death rates were 3.2% (CAS) and 3.7% (CEA) (P = not significant). Cranial nerve injury only occurred in the CEA patients (2.3%). Perioperative hemodynamic instability was more common among patients in the CAS group (11.9% versus 4.1%, P <.05).

CONCLUSIONS

Percutaneous carotid stenting with neuroprotection provides comparable clinical success to CEA performed under local anesthetic. Further studies are warranted to validate the long-term efficacy of CAS and to elucidate patient selection criteria for endovascular carotid revascularization.

Review of developments in anesthesia for carotid endarterectomy

PURPOSE OF REVIEW

Analysis of recent data indicates a clear benefit of carotid endarterectomy for symptomatic patients with high-grade carotid artery stenosis, and a marginal benefit for asymptomatic patients. Despite myriad challenges presented by patients undergoing carotid endarterectomy, excellent outcomes have been achieved and many centers have shown the technique to be safe as an outpatient procedure for specific populations. Greater attention to comorbidities and their management in the perioperative period is increasingly important as older and more complex patients present for invasive treatment of carotid disease. Scientific study aimed at defining which characteristics merit our attention will only lead to improved outcomes and greater understanding of carotid disease, endarterectomy and anesthesia. While controversial, the efficacy, safety, and durability of stenting and angioplasty have improved in recent years. Potential advantages of stenting and angioplasty of the carotid artery include avoiding cranial nerve damage, wound hematoma, and general anesthesia. Staying abreast of the science regarding such endovascular therapies will be increasingly important.

RECENT FINDINGS

The major areas of investigative interest include patient selection, anesthetic technique, and monitoring for carotid endarterectomy, and durability of stenting and angioplasty of the carotid artery.

SUMMARY

Patients with significant comorbidities may be managed safely by a variety of anesthetic techniques. Maintaining hemodynamic stability and monitoring cerebral oxygen delivery remain important goals of perioperative management. Recent data regarding the durability and safety of stenting and angioplasty of the carotid artery suggest that outcomes may approach those of carotid endarterectomy.

New technologies meeting old professional boundaries: the emergence of carotid artery stenting

BACKGROUND

Carotid artery stenosis is common and costly. Opinions differ in regard to the impact that carotid angioplasty and stenting (CAS) will have. Vascular surgeons, cardiologists, interventional radiologists, and neurologists all have a stake in the uptake of CAS. We sought to explore physicians' views about the safety and efficacy of CAS and the negotiation of professional boundaries in the treatment of carotid stenosis.

STUDY DESIGN

We performed a qualitative analysis of key informant interviews with 15 physicians, including four internationally renowned key opinion leaders, representing five medical centers with differing experience adopting CAS.

RESULTS

Variation in beliefs about the safety and efficacy of CAS within specialties was overshadowed by variation across the specialties examined. Most informants emphasized the strengths of their specialty in adopting CAS, including frequent patient care (vascular surgery, cardiology, and neurology), extensive catheter experience (cardiology, interventional radiology), and intimate knowledge of the anatomy of vascular and neurovascular disease (vascular surgery, neurology). Several themes were mentioned in regard to the diffusion of CAS, including risks of premature diffusion into low risk populations and the role of patient preferences in CAS uptake. The most common theme in regard to local management of CAS was the strength of interdisciplinary collaboration in the management of patients with carotid artery stenosis.

CONCLUSIONS

CAS challenges physicians from several specialties to safely and effectively manage the uptake of an emerging technology crossing traditional specialty lines. Local collaboration of individual physicians and the departments and professional organizations they comprise, will have an important impact on how this technology is adopted.

Patient selection for revascularization in cervical carotid artery disease: angioplasty and stenting vs. endarterectomy

Cervical carotid stenosis is a major cause of stroke and disability. Although carotid endarterectomy is an established and effective treatment for some patients with carotid artery stenosis, angioplasty and stenting has emerged in recent years as a viable alternative, particularly for patients who may be less suited for surgery. This article reviews patient selection for the two alternative approaches. The authors review the findings of the major clinical trials of carotid endarterectomy, summarize the development of carotid angioplasty and stenting, and identify patient characteristics that may guide selection of surgical or endovascular treatment.

Carotid artery stenting

Efficacy for carotid artery stenting (CAS) has not been confirmed by randomized clinical trial methodology in conventional risk patients. Although carotid endarterectomy (CEA) is considered the preferred method for carotid revascularization in the management of patients with symptomatic and asymptomatic extracranial carotid occlusive disease, comparisons between CAS and CEA are now underway. In North America, the CREST (Carotid Revascularization Endarterectomy versus Stent Trial) protocol is now completing its lead-in or credentialing phase as randomization of cases is initiated. In Europe, the CAVATAS (Carotid and Vertebral Artery Transluminal Angioplasty Study) and Stent Protected Angioplasty versus Carotid Endarterectomy trials are recruiting symptomatic patients for randomization between CEA and CAS. It is anticipated that these trials will publish definitive results within the next 1 to 3 years, and help guide the referral of patients for CAS and CEA in the future.

Axillary Artery Access for Interventional Procedures

PURPOSE

To evaluate axillary artery access for the interventional treatment of carotid or splanchnic arteries that have angulated takeoff or complex anatomy when larger catheters (up to 9 F) are needed.

TECHNIQUE

The axillary artery approach was used to treat the left internal carotid artery (ICA) in 3 patients (2 angulated takeoffs and 1 bovine arch) and a celiac axis aneurysm. An 8-F, 45-cm-long introducer sheath was inserted for the carotid procedures, whereas a 9-F, 90-cm sheath was chosen for the celiac aneurysm. Cerebral protection and stenting were successfully performed in all carotid patients; an 8x40-mm stent-graft was implanted to exclude the celiac artery aneurysm. An 8-F vascular closure device was used in the axillary arteries; hemostasis was immediate, and no hematoma or other complications were recorded in follow-up.

CONCLUSIONS

This preliminary experience revisits the axillary approach as an alternative access route for interventional procedures. In association with a vascular closure device, this approach should be considered as a useful and safe option for those interventional procedures in which larger sheaths or catheters are required to cope with difficult arterial anatomies.

Octogenarians with contralateral carotid artery occlusion: a cohort at higher risk for carotid endarterectomy?

PURPOSE

Carotid angioplasty and stenting has been proposed as a treatment option for carotid occlusive disease in patients at high risk, including those 80 years of age or older or with contralateral carotid occlusion. We analyzed 30-day mortality and stroke risk rates of carotid endarterectomy (CEA) in patients aged 80 years or older with concurrent carotid occlusive disease.

METHODS

From a retrospective review of 1000 patients undergoing 1150 CEA procedures to treat symptomatic and asymptomatic carotid lesions over 13 years, we identified 54 patients (5.4%) aged 80 years or older with concurrent contralateral carotid occlusion. These patients were compared with 38 patients (3.8%) aged 80 years or older with normal or diseased patent contralateral carotid artery and 81 patients (8.1%) younger than 80 years with contralateral carotid occlusion. All CEA procedures involved either standard CEA with patching or eversion CEA, and were performed by the same surgeon, with the patients under deep general anesthesia and cerebral protection involving continuous perioperative electroencephalographic monitoring for selective shunting. Shunting criteria were based exclusively on electroencephalographic abnormalities consistent with cerebral ischemia.

RESULTS

The 30-day mortality and stroke rate in patients aged 80 years or older with concurrent contralateral carotid occlusion was zero.

CONCLUSIONS

The concept of high-risk CEA needs to be revisited. Patients with two of the criteria considered high risk in the medical literature, that is, age 80 years or older and contralateral carotid occlusion, can undergo CEA with no greater risks or complications. Until prospective randomized trials designed to evaluate the role of carotid angioplasty and stenting have been completed, CEA should remain the standard treatment in such patients.

Carotid endarterectomy in high-risk patients: A challenge for endovascular procedure protocols

BACKGROUND

Many studies have sought to identify certain patient population subsets that may be more appropriate for carotid angioplasty and stenting (CAS). Current CAS protocols include "high-risk" patients. The goal of this study was to compare the perioperative outcome of carotid endarterectomy (CEA) between high-risk and non-high-risk patients.

METHODS

During a 54-month period, 392 consecutive CEAs were performed in 363 patients (29 bilateral) by a single surgeon and entered prospectively into a registry. A high-risk patient subset (126, 35%) was defined by the presence of a severe medical comorbidity (ie, cardiac dysfunction, pulmonary dysfunction, renal insufficiency) or particular anatomic features (ie, contralateral carotid occlusion, ipsilateral carotid restenosis after CEA, and "high" carotid bifurcation). Of the 126 CEAs, 96 (76%) were performed for symptomatic lesions. Endpoints of the study were perioperative stroke, cardiac complication, or death.

RESULTS

Overall, there were three ischemic strokes (1%) and four cardiac complications (1%). None of the patients died. The stroke and cardiac complication rates for the high-risk and non-high-risk groups were similar (1/126, 1% versus 2/237, 1% and 3/126, 2% versus 1/237, 1%, respectively), but the cardiac morbidity rate was statistically higher in patients with severe medical comorbidity (P=.03), especially in the subset with cardiac dysfunction (P=.005).

CONCLUSIONS

CEA can be performed in high-risk patients with perioperative neurologic and cardiac complication rates comparable with those recorded in other patients. The definition of a "high-risk" patient should not be considered per se a reason to abandon CEA in favor of CAS.

Rationale and status of randomized controlled clinical trials in carotid artery stenting

Efficacy for carotid artery stenting (CAS) has not been confirmed by randomized clinical trial methodology. Although carotid endarterectomy (CEA) is considered the preferred method for carotid revascularization in the management of patients with asymptomatic and symptomatic extracranial carotid occlusive disease, comparisons between CAS and CEA are now underway. In North America, the CREST (Carotid Revascularization Endarterectomy versus Stent Trial) protocol is now completing credentialing cases as randomization of cases is initiated. In Europe, the CAVATAS (Carotid and Vertebral Artery Transluminal Angioplasty Study) and SPACE (Stent Protected Angioplasty versus Carotid Endarterectomy) trials are recruiting symptomatic patients for randomization between CEA and CAS. It is anticipated that these trials will publish definitive results within the next 1-3 years and help guide the referral of patients for CAS and CEA in the future.

Synchronous Carotid Endarterectomy and Retrograde Endovascular Treatment of Brachiocephalic or Common Carotid Artery Stenosis

OBJECTIVES

To retrospectively evaluate the safety and the long-term results of retrograde brachiocephalic and common carotid angioplasty and stenting (AS) performed for >70% stenosis synchronously with the carotid endarterectomy (CEA).

PATIENTS

Sixteen patients operated between April 1999 and March 2002.

RESULTS

14/16 procedures were successful. There was no neurological morbidity or mortality. Per-operative angiography showed the optimal stent positioning and patency of both proximal and distal arteries in all patients. In the follow-up, all patients showed patency of the treated vessels without restenosis and the absence of any cerebrovascular symptoms.

CONCLUSION

Intra-operative retrograde AS combined with CEA is an effective, safe and durable alternative to conventional surgery when a tandem significant proximal lesion is identified in a patient with an high grade carotid stenosis.

Cerebrovascular disease

PURPOSE OF REVIEW

Carotid endarterectomy remains the preferred surgical intervention for the prevention of stroke among patients with extracranial cerebrovascular disease. Subgroup analyses of the results of several multicentre trials have contributed substantially to our understanding of the appropriate selection of patients and the perioperative risk associated with this procedure.

RECENT FINDINGS

This review describes recent advances in our understanding of the appropriate use of carotid endarterectomy, and outlines recent developments and strategies that are likely to influence the perioperative care of these patients.

SUMMARY

As current clinical guidelines for the use of carotid endarterectomy unfold, anaesthesiologists can expect to care more frequently for older patients and those at increased risk of complications. The perioperative management of co-existing diseases, particularly the control of hypertension and the strategies aimed at reducing the risk of cardiac complications, will contribute substantially to reducing perioperative morbidity and mortality.

Carotid artery stenting: analysis of data for 105 patients at high risk

OBJECTIVES

Carotid artery stenting (CAS) has been recommended as an alternative to carotid endarterectomy (CEA) by some clinicians. However, recently published clinical trials have reported 30-day stroke and death rates of 10% to 12%. This prompted review of our experience with CAS in patients at high risk, to document our results and guide further use of CAS.

METHODS

From September 1996 to the present, we performed 114 consecutive CAS procedures in 105 patients. Sixty-three patients were men (60%) and 42 patients were women (40%), with mean age of 70 years (range, 45-93 years). Indications for CAS included recurrent stenosis after previous CEA in 74 patients (65%), primary lesions in 32 patients at high risk (28%), and carotid stenosis with previous ipsilateral radiation therapy in 8 patients (7%). Asymptomatic stenosis (>80%) was managed in 70 patients (61%), and symptomatic lesions (>50%) were treated in 44 patients (39%).

RESULTS

CAS was technically successful in all patients. Mean severity of stenosis before CAS was 87% +/- 6%, compared with 9% +/- 4% after CAS. Two patients (1.9%) died, 1 of reperfusion-intracerebral hemorrhage and 1 of myocardial infarction 10 days after discharge; and 1 patient (0.95%) had a stroke (retinal infarction), for a 30-day stroke and death rate of 2.85%. Two patients (1.9%) had transient neurologic events. No cranial nerve deficits were noted. No neurologic complications have been noted in the last 27 patients (26%).

CONCLUSIONS

A 30-day stroke and death rate of 2.85% in our experience demonstrates acceptability of CAS as an alternative to repeat operation or primary CEA in patients at high risk or in patients with radiation-induced stenosis. We recommend further clinical investigation of CAS and participation in clinical trials by vascular surgeons.

Management of the first-time transient ischaemic attack

The assessment and management of patients with a suspected transient ischaemic attack of the brain or eye is a daily task in busy emergency departments. They are common, affecting about 50 per 100,000 population each year. Conditions which mimic a transient ischaemic attack are even more common (e.g. migraine aura, partial seizures, benign paroxysmal positional vertigo, hysteria). This comprehensive review outlines an approach to the management of this complex and challenging problem.

Internal to external carotid artery transposition to repair recurrent stenosis after carotid artery stenting

Recently, carotid artery stenting (CAS) has emerged as a treatment option for carotid artery stenosis. Since the procedure is new, management of its complications is not standardized. This case report describes one method of arterial reconstruction after failed CAS. A 64-year-old male underwent CAS of his right internal carotid artery (ICA) for an asymptomatic 65% stenosis. Seven months later the stented area had narrowed to 95%. Arteriography revealed that the common and external carotid arteries (ECA) were free of disease so we elected to perform a transposition of the distal ICA onto the proximal ECA. The ECA and its branches were completely mobilized and the ascending pharyngeal and lingual arteries divided. The ICA was divided distal to the stent. Transection of the occipital artery provided an arteriotomy for an end ICA to side ECA anastamosis, thus preserving ECA flow. Postoperative surveillance after 8 months has revealed no recurrent stenosis. Operative repair of restenosis after CAS may be challenging if standard endarterectomy is not possible. Other options for reconstruction are feasible but if the common and external carotid arteries are disease-free, an ICA to ECA transposition provides a simple all-arterial repair that avoids bypass and prosthetic material.

Efficacy of a proximal occlusion catheter with reversal of flow in the prevention of embolic events during carotid artery stenting: an experimental analysis

OBJECTIVE

The role of percutaneous angioplasty and stenting of carotid bifurcation lesions has been limited by its potential for producing embolic debris. We evaluated the efficacy of a proximal occlusion catheter (POC) in the prevention of embolic events during carotid artery stenting. In addition, pressure measurements relevant to the clinical application of this device were obtained from 10 patients undergoing carotid endarterectomy.

METHODS

The POC is a guiding catheter with an occlusion balloon attached on the outside of the catheter at its distal end. Occlusion of the common carotid artery (CCA) was achieved by inflating the balloon while access to carotid bifurcation lesions was obtained through the inner lumen. The POC was inserted in the CCA of 10 dogs via the femoral artery. The side port of the POC was connected to a sheath placed in the femoral vein, thereby creating an external arteriovenous shunt. Ten artificial radiopaque particles simulating embolic particles and contrast agent were introduced in the CCA and monitored fluoroscopically. As a control, the same procedure was performed with a standard guiding catheter without an occlusion balloon. In 10 patients undergoing carotid endarterectomy, the internal carotid artery (ICA) and external carotid artery stump pressures and the pressure in the internal jugular vein were measured.

RESULTS

Without the external arteriovenous shunt, in all animals there was prograde flow in the distal CCA despite CCA occlusion. This flow was derived from the thyroid artery. However, once the arteriovenous shunt was activated, reversal of flow in the distal CCA was achieved in each animal, and all the artificial particles were recovered from the side port of the POC. In the control group, each particle embolized to the brain (100%, P <.01). In the patients, the mean stump pressures in the ICA and external carotid artery and the jugular vein pressure were 51.8 +/- 14.2, 62.2 +/- 15.1, and 6.5 +/- 3.5 mm Hg, respectively. In each case, the jugular vein pressure was the lowest among the three.

CONCLUSIONS

Obtaining proximal CCA control by inflating the POC does not sufficiently prevent embolization. However, reversal of flow in the ICA can always be created with the external shunt, which effectively prevents embolization. Thus, POC may markedly lower procedural stroke rates during carotid artery stenting. The ability of POC to prevent embolization before crossing the lesion with a guidewire may be an important advantage over other distal protection devices.

Reconstructive surgery of the extracranial arteries

The first carotid endarterectomy (CEA) is usually accredited to Eastcott who reported in 1954 the successful incision of a diseased carotid bulb with end-to-end anastomosis of the internal carotid artery (ICA) to the common carotid artery (CCA). During the following years surgeons were quick to adopt and improve the intuitively attractive procedure. But by the early to mid 1980s several leading neurologists began to question the growing number of CEAs performed at that time. Six major CEA trials were then designed which are now completed or nearing completion. Most conclusive data are available from the North American Symptomatic Carotid Endarterectomy Trial (NASCET) for symptomatic carotid disease, and from the Asymptomatic Carotid Atherosclerosis Study (ACAS) for asymptomatic carotid disease. The key result of these studies is that CEA is beneficial to high grade symptomatic and asymptomatic carotid stenosis. While the benefit in symptomatic disease is clear, it may be negligible in asymptomatic patients suffering from other medical conditions, the most important being coronary artery disease. Since the conclusions from the different studies vary significantly, guidelines and recommendations with regard to CEA have been issued by a number of interest groups, so-called consensus conferences. The best known guidelines are published by the American Heart Association (AHA). However, the practice of interest groups to issue guidelines is currently being criticized, the main reason being that interest groups have different ideas and all claim the right to issue guidelines. At present we recommend CEA for symptomatic high-grade stenosis in patients without significant coincident disease. With regard to asymptomatic stenosis we suggest surgery to otherwise healthy patients if the stenosis is very narrow or progressive. Preoperative evaluation has changed over the years. Currently we recommend duplex sonography in combination with intra- and extracranial magnetic resonance angiography (MRA). Concurrent coronary artery disease is a major consideration in the perioperative management, and the use of a specific algorithm is recommended. Surgery is performed under general anaesthesia with intraoperative monitoring such as electroencephalography (EEG) and transcranial Doppler (TCD). A temporary intraluminal shunt is used selectively if after cross-clamping the flow velocity in the middle cerebral artery (MCA) falls to below 30 to 40% of baseline. For years we employed routine barbiturate neuroprotection during cross-clamping. At the present time we use barbiturate selectively, if the flow velocity in the MCA falls to below 30 to 40% of baseline and if the use of a temporary intraluminal shunt is not possible due to difficult anatomic conditions. The reason to abandon systematic barbiturate protection was to accelerate recovery from anaesthesia. Our patients are monitored overnight on the ICU or a surveillance unit. Routine hospitalization after surgery is 5 to 7 days with a control duplex sonography being performed prior to discharge. A number of details with regard to surgical technique and perioperative management are a matter of discussion. Our surgical routine is described here step by step. Such management resulted in 6 major complications among the 402 cases with 4 of cardiopulmonary and 2 of cerebrovascular origin. For the future we can expect the development of percutaneous transluminal techniques competing with standard carotid endarterectomy. At the present time several comparative studies are under way. Irrespective of the technical approach to treat carotid stenosis, several other issues have to be clarified before long. One of the major unresolved items is the timing of treatment after completed stroke. In this regard prospective trials need to be performed. Although numerically not as important as carotid stenosis, vertebral artery (VA) and subclavian artery (SA) stenoses are more and more accepted as indication for surgical

In-stent restenosis after carotid angioplasty-stenting: incidence and management

PURPOSE

Carotid angioplasty-stenting (CAS) has been advocated as an alternative to carotid endarterectomy (CEA) in patients with restenotic lesions after prior CEA, primary stenoses with significant medical comorbidities, and radiation-induced stenoses. The incidence of restenosis after CAS and its management remains ill defined. We evaluated the incidence and management of in-stent restenosis after CAS.

METHODS

Patients with asymptomatic (61%) and symptomatic (39%) carotid stenosis of > or = 80% underwent CAS between September 1996 and May 2000; there were 50 procedures and 46 patients (26 men and 20 women). All patients were followed up clinically and underwent duplex ultrasonography (DU) at 3- to 6-month intervals. In-stent restenoses > or = 80% detected with DU were further evaluated by means of angiography for confirmation of the severity of stenosis.

RESULTS

No periprocedural or late strokes occurred in the 50 CAS procedures during the 30-day follow-up period. One death (2.2%) that resulted from myocardial infarction was observed 10 days after discharge following CAS. During a mean follow-up period of 18 +/- 10 months (range, 1-44 months), in-stent restenosis was observed after four (8%) of the 50 CAS procedures. Angiography confirmed these high-grade (> or = 80%) in-stent restenoses, which were successfully treated with balloon angioplasty (3) or angioplasty and restenting (1). No periprocedural complications occurred, and these patients remained asymptomatic and without recurrent restenosis over a mean follow-up time of 10 +/- 6 months.

CONCLUSIONS

We recommend CAS for post-CEA restenosis, primary stenoses in patients with high-risk medical comorbidities, and radiation-induced stenoses. In-stent restenoses occurred after 8% of CAS procedures and were managed without complications with repeat angioplasty or repeat angioplasty and restenting.

Carotid endarterectomy. Which patients can benefit?

Carotid endarterectomy for carotid artery stenosis is valuable for some patients, but not all. Results of clinical trials in symptomatic and asymptomatic patients provide guidance on use of this common vascular procedure. The authors of this article describe the controversies and concerns with the procedure and give their recommendations based on study results.

Balloon-protected carotid angioplasty

OBJECTIVE

We describe a method of protecting the distal cerebral circulation during carotid angioplasty and report results using the technique in 17 procedures.

METHODS

Eleven men and five women with carotid stenoses ranging in severity from 70 to 95% underwent the procedure. The technique was used bilaterally in one patient. A compliant silicone balloon was used to occlude the distal internal carotid artery during the angioplasty phase, when the largest number of emboli are generated. After angioplasty, debris was then flushed into the external circulation while the occlusion balloon remained inflated. The subsequent passage of an exchange guidewire through the angioplasty catheter, with the occlusion balloon deflated, allowed continuous guidewire access across the area of stenosis and facilitated the subsequent placement of a stent.

RESULTS

The technique was successful in 16 (94%) of 17 procedures. In the one patient in whom the occlusion balloon could not be advanced across the stenosis, the patient experienced a transient ischemic attack after subsequent angioplasty that was performed without protection. Otherwise, no complications occurred among the 15 patients undergoing successful, balloon-protected angioplasty. Inflation times for the occlusion balloon did not exceed 5 minutes in any patient.

CONCLUSION

This method of cerebral protection prevents the intracranial embolization of thrombus and atherosclerotic debris, while allowing continuous guidewire access across the site of stenosis. The success of this technique and a similar method used by Theron et al. supports the use of balloon protection as a means of reducing the risk of stroke associated with carotid angioplasty.

Efficacy of a filter device in the prevention of embolic events during carotid angioplasty and stenting: An ex vivo analysis

OBJECTIVE

Although percutaneous angioplasty and stenting (PTAS) of carotid bifurcation lesions is feasible and appropriate for surgically inaccessible lesions, its general role and comparative value remain unclarified. Moreover, the acceptance of carotid PTAS has been limited by its potential for producing embolic debris. This study used an ex vivo model to evaluate the efficacy of a novel filter device to entrap emboli during PTAS of human carotid plaques.

METHODS

Eight carotid bifurcation plaques were obtained from patients who underwent carotid endarterectomy for high-grade atherosclerotic stenosis (>90%). The mean age of the patients was 63 years, and six patients were symptomatic. Each plaque was encased with polytetrafluoroethylene material to simulate adventitia and was connected to a perfusion circuit, which provided continuous flow through the plaque. The filter device consisted of an expandable polymeric membrane with multiple micro pores that was attached to the distal end of a 0.014-in wire with a shapeable tip. This filter was encased in a delivery catheter. With fluoroscopic guidance, the filter wire was passed through the stenosis and the delivery catheter was then retracted to open the filter to capture particles released into the distal internal carotid artery. PTAS with a self-expandable stent then was carried out over the filter wire. The particles released during the initial filter passage, those captured in the filter, and those that flowed through or around the filter (missed) were collected and analyzed with light microscopy.

RESULTS

Filter deployment, PTAS, and filter retrieval were achieved successfully with each lesion. Because the filter has a low crossing profile, it passed through the stenoses smoothly and only produced occasional small particles. PTAS improved the angiographic stenosis from 96.2% +/- 3.7% to 1.3% +/- 1.6%. The mean number and the maximum size of the particles that were released during initial filter passage, missed, and captured by the filter device were 3.1 and 500 microm, 2.8 and 360 microm, 20.1 and 1100 microm, respectively. Most of the particles and those of large size were released during PTAS. The filter captured 88% of these particles.

CONCLUSION

These study results show that this filter device, at least in this model, did not add complexity to the interventional procedure itself. Furthermore, the filter may markedly decrease embolic events during carotid PTAS and expand the indications for this procedure.

Saphenous vein interposition graft for recurrent carotid stenosis after prior endarterectomy and stent placement. Case report

Although the use of carotid artery stents is increasing, the management of recurrent stenosis after their placement is undefined. The authors report on a patient who underwent two left carotid endarterectomies followed by left carotid angioplasty and stent placement for recurrent stenosis. A third symptomatic recurrence was subsequently managed by placement of a saphenous vein interposition graft from the common carotid artery to the distal cervical internal carotid artery. The patient remained without hemispheric or retinal ischemia at his 5-month follow-up visit. Interposition grafting should be considered as a treatment option for carotid restenosis after initial endarterectomy and stent placement.

Carotid restenosis: operative and endovascular management

PURPOSE

Surgical management of carotid restenosis (CR) after carotid endarterectomy (CEA) has been associated with a higher perioperative complication rate than that of primary CEA. We recently used carotid angioplasty-stenting (CAS) as an alternative to operative management in patients who had undergone CEA within three years, and we retrospectively compared these results with those of operative management of CR and the overall results of CEA.

METHODS

CEA was performed on 1065 adult patients (58% symptomatic, 42% asymptomatic), 62% of whom were men (n = 660) and 38% of whom were women (n = 405), from 1989 to 1997. Before our initiation of a program of CAS, 16 operative procedures (1.9% of CEAs) were performed for CR in 14 adult patients (7 women and 7 men). During the last 20 months, CAS was used in the management of 17 CRs (16 patients; 9 women and 7 men).

RESULTS

The 30-day stroke morbidity-death rate for all CEAs (n = 1065) was 1.4%; 11 strokes (1. 0%) occurred (4 major strokes with disability and 7 strokes with minor or no disability), and 4 deaths (0.4%) occurred (2 deaths caused by myocardial infarction, 1 caused by intracranial hemorrhage, and 1 caused by stroke). Operative management of CR (n = 16) included patch angioplasty in 12 cases (autologous vein patches in 10 cases and synthetic patches in 2 cases), whereas interposition grafting was used in 4 cases (saphenous vein in 3 instances and synthetic [polytetrafluoroethylene] in one case). No strokes or deaths were observed. One recurrent laryngeal nerve palsy occurred (6.2%). Among the 16 patients undergoing 17 CAS procedures, the technical procedures were accomplished in all patients. No strokes or deaths occurred. No recurrent restenoses (50% or greater) have been identified within or adjacent to the CAS procedures.

CONCLUSION

CR caused by myointimal hyperplasia can be managed by operative techniques or CAS with comparable periprocedural complications. Although long-term follow-up will be required to determine the incidence of recurrent restenosis, CAS may become the preferred procedure in these cases. A randomized clinical trial ultimately will be necessary to determine the role of CAS, as compared with that of operative management.