Carotid Stenting Done Exclusively by Vascular Surgeons

Abstract

Background:

Percutaneous CAS may well replace CEA as standard of care. CAS has been performed largely by interventional cardiologists; however, with recent Food and Drug Administration approval, vascular surgeons are now hurriedly attempting to obtain the requisite endovascular skills. Reported are our 30-day and midterm outcomes of CAS.

Methods:

Retrospective review of 175 cervical carotid stenoses treated with elective CAS from April 2001 to February 2005. All procedures were performed under local anesthesia via percutaneous femoral access in an operating room angiosuite. Mechanical cerebral protection was used in 90% of cases. Data analysis includes demographics, procedural records, and duplex exams over a mean follow-up of 21 months.

Results:

Mean age is 70 years (74% men and 26% women). Preprocedural neurologic symptoms were present in 32%. Intraoperative complications included 2 seizures (1.1%) and 4 asystolic arrests (2.3%), all managed medically without sequelae. Over the 30-day follow-up there were no deaths, no myocardial infarctions (MIs), 2 major strokes (1.1%), 2 minor strokes (1.1%), 3 transient ischemic attacks (TIAs) (1.7%), and 1 major access-site complication (0.6%). At late follow-up, 3 cases (1.7%) of restenosis occurred; all were treated with repeat angioplasty and remain patent. One (0.6%) asymptomatic occlusion was detected at 6-month follow-up. There have been no late carotid-related complications or deaths.

Conclusions:

Vascular surgeons possessing advanced catheter-based skills can safely perform CAS and achieve perioperative results comparable to CEA. Such skills are crucial to those surgeons intent on the future management of carotid occlusive disease.

Retrospective review of 175 cervical carotid stenoses treated with elective carotid angioplasty and stenting (CAS). Vascular surgeons possessing advanced catheter-based skills can safely perform CAS and achieve perioperative results comparable to carotid endarterectomy (CEA).

Carotid artery angioplasty and stenting (CAS) has emerged as one of the most controversial procedures in the era of modern medicine.¹ Some specialties have openly embraced this technology as a means to treat carotid artery occlusive disease, whereas other specialties have seen a tremendous rift arise within their specific field regarding the use of CAS for carotid stenosis treatment. Within surgery, specifically vascular surgery, several groups have recently fought hard to dispel the notion of “high-risk” patients for carotid endarterectomy (CEA), and to confirm the position of CEA as the standard of care for the treatment of carotid artery stenosis.^2–4 Others have actively embraced CAS trials, both industry-sponsored and independent, working toward acknowledgment of CAS as an acceptable treatment option for carotid revascularization.^5,6

The last decade has witnessed an exponential growth in the field of percutaneous transluminal arterial interventions, facilitated by device innovations, technical refinements, and knowledge allowing careful patient selection. Despite early descriptions of CAS, only in the past few years has there been widespread interest in this modality.^7,8 Vascular surgeons, neurosurgeons, interventional cardiologists, neuroradiologists, and neurologists recognize the seriousness of the changing technology and have called for and begun prospective randomized studies with rigorous oversight to help guide the debate surrounding CAS.⁹ Furthermore, these groups have worked both together and in isolation to create training and credentialing standards.¹⁰ Unfortunately, vascular surgeons, representing the minority performing CAS, remain staunch advocates of CEA and have largely scorned CAS. The tide may change with the recently presented results of trials showing better outcomes in high-risk patients treated with CAS.^11,12 In light of this, we review our immediate and midterm experience with CAS performed exclusively by vascular surgeons in an operating room angiosuite. The contemporary results of patients undergoing CEA at the same institution are provided as a point of comparison.

MATERIALS AND METHODS

Patient Characteristics

From April 2001 to February 2005, 175 consecutive cervical carotid stenoses in 168 patients were treated with CAS at Northwestern Memorial Hospital and the Jesse Brown VA Medical Center. A control group of carotid endarterectomy patients was reviewed, consisting of 347 CEAs in 341 patients at Northwestern Memorial Hospital between February 2000 and February 2005.

A total of 175 CAS procedures were performed in 168 patients. Cerebral protection devices were used in 157 procedures (90%). These devices included filter-protection (37%) and distal balloon-occlusion (53%) systems. Cerebral protection devices were not used in 10% of the procedures. This was because of the unavailability of devices early in our experience, the inability to pass the device, or for treatment of lesions through a retrograde approach. Stents were placed in 172 of 175 cases (98%). An ultrasound follow-up study was performed on postoperative day 1, documenting patency of all treated arteries. The clinical characteristics are shown in Table 1. Mean age for the CAS patients was 70.0 years (74% men and 26% women) and 69.9 years for the CEA patients (60% men and 40% women). Preprocedural neurologic symptoms were present in 32% of the CAS group and in 43% of the CEA group. Indications for CAS treatment included previous neck surgery and/or external beam neck irradiation (13), recurrent stenosis (31), fibromuscular dysplasia (1), contralateral carotid artery occlusion (7), and severe comorbidities. Carotid stenoses in the CAS group were located at the extracranial internal carotid artery bifurcation (161 cases), common carotid artery (10), functional external carotid artery (1), separate stenoses of the internal carotid artery and common carotid artery (2), or previous venous bypass graft (1). Among the CAS group the majority were classified as “high-risk,” whereas the majority of CEA patients were standard risk.

TABLE 1. CAS Baseline Patient Characteristics

The overall rate of neurologic complications (minor and major stroke) and non-neurologic complications (MI, death, access-site complications, cranial nerve injuries, and hematoma formation) were reviewed. Minor stroke was defined as any new neurologic deficit persisting beyond 24 hours without increasing the National Institutes of Health (NIH) stroke scale by more than 3 points. Major stroke was any new neurologic event persisting more than 30 days and/or increasing the NIH stroke scale more than 3 points. Patients undergoing CAS were required to have either symptomatic (≥50% diameter) or asymptomatic (≥80% diameter) stenoses of the carotid artery. Patients were excluded if they had a major neurologic deficit or illness impeding informed consent. With respect to CAS patients, they were excluded if they had severe renal insufficiency (creatinine >3 mg/dl) or peripheral vascular disease precluding femoral artery access. All patients were reviewed under Institutional Review Board approved protocols at the listed institutions.

Surgeons

All procedures in this review were performed by one of 3 surgeons with extensive catether-based experience using 0.014-inch–based platforms. Cerebral protection devices were employed in flow-models under supervision before doing an actual case; in the future, the use of simulators will likely be added. At least 20 cases were done with an experienced operator prior to performing additional cases independently.

Operative Procedure

CAS was performed in an operating room with dedicated endovascular capabilities. Preoperatively, the patients’ diagnostic studies included carotid duplex ultrasonography with magnetic resonance angiography of the neck and cerebral circulation or a carotid/cerebral angiogram. All patients were loaded with clopidogrel (Plavix) at least 24 hours before stenting and each patient was also given Plavix 75 mg daily, including the morning of the procedure. In addition, each patient was given aspirin 325 mg on the morning of the procedure. Aspirin and Plavix were continued in all patients for at least 30 days after the procedure, followed by only one or the other indefinitely.

Percutaneous access was obtained through a common femoral artery puncture. A J-wire (0.035 in) and then a short 6 Fr sheath were used to secure access. A marker pigtail catheter (5 Fr, 110 cm long) was placed in the ascending arch under fluoroscopy. A left anterior oblique aortogram at an angle of 30° was obtained. Selection of the common carotid artery was achieved using a Vitek Catheter (Cook, Inc., Bloomington, IN) or a DAV catheter (Cook, Inc.). Systemic heparin (100 units/kg intravenous) was given to obtain an activated clotting time of 250–300 sec. A Storq wire (300 cm long, Cordis Corporation, Miami Lakes, FL) was used to cannulate the common carotid artery and then “buried” distally in the external carotid artery. With the Storq wire in place, the 6 Fr sheath was replaced with a 100-cm–length 6 or 7 Fr Shuttle Sheath (Cook, Inc.). The distal tip of the shuttle sheath was placed 2–4 cm proximal to the carotid bifurcation. Angiograms were performed of the intracranial and the extracranial arteries with at least 2 different views, anteroposterior and lateral.

The lesion was then crossed with either a 0.014 inch wire-based filter or distal balloon-occlusion protection system. Earlier on, the choice of the mechanical cerebral protection device used was based on availability; more recently, it was based on the crossing profiles and flexibility in cases of severely stenotic or tortuous target lesions. The protection device was deployed in the distal extracranial internal carotid artery, and appropriate deployment and positioning were documented by angiography. The stenosis was then predilated with a low-profile monorail 4- × 20-mm balloon. Intravenous atropine (0.5–1 mg) was administered immediately prior to predilatation for de novo lesions. Stent size was based on the diameter of the trailing end of the stenotic segment. A self-expanding nitinol stent was deployed over the wire and then postdilated using a 5- × 20-mm balloon. No drug-eluting stents were used. The protection device was then retrieved. Completion angiograms of the intracranial and extracranial vessels were done, employing anteroposterior and lateral views.

A retrograde approach was used to angioplasty and stent the origin of the common carotid artery. A 2-cm incision was made over the common carotid artery. After isolating the vessel, it was cannulated and a wire was advanced across the lesion. A stent was then positioned and deployed over the wire. Postdilatation occurred based on the angiographic result. No protection device was used.

Postoperatively, the patients were sent to the recovery room. If they remained hemodynamically stable, they were then sent to the regular ward. On postoperative day 1, the patients underwent carotid duplex ultrasonography as a baseline study. Surveillance carotid duplex ultrasound was performed at 3, 6, 9, 12, 18, and 24 months, and then annually. Daily Plavix (75 mg) and aspirin (325 mg) were prescribed for at least 1 month and preferably indefinitely.

Patients undergoing CEA did not receive clopidogrel preoperatively. All CEA patients received general anesthesia and underwent either eversion endarterectomy or a standard endarterectomy with patch closure and selective shunting.

Statistical Analysis

All statistical analyses were performed with SPSS software (SPSS, Chicago, IL). Data are expressed as mean ± standard error of the mean. All probability values were 2-tailed and values of P < 0.05 were considered statistically significant.

RESULTS

Thirty-Day Outcome

At 30 days, a total of 18 complications (10%) were recorded after CAS (Table 2). Intraoperative complications included 2 seizures (1.1%) and 4 asystolic arrests (2.3%); all managed medically without sequelae. During this time, there were no deaths or MIs. Neurologic complications included 2 major ipsilateral hemispheric strokes (1.1%), 2 minor posterior strokes (1.1%), and 3 TIAs (1.7%). Access-site complications consisted of 3 retroperitoneal bleeds (1.7%), one of which required operative repair, transfusion, and a prolonged hospital stay of 11 days. There were also 2 femoral artery pseudoaneurysms (<3 cm): one resolved without intervention and the other was treated with thrombin injection.

TABLE 2. Neurologic Complications

At our institution, early CAS results compared favorably to contemporary CEA results: 1 major stroke (0.3%), 2 minor strokes (0.6%), and 3 TIAs (0.9%). CAS had an overall non-neurologic complication rate of 6.3% compared with CEA at 10.4%. Non-neurologic complications include: retroperitoneal hematoma, femoral pseudoaneurysm, intraoperative asystole, seizure, neck hematoma, cranial nerve palsy, and MI. Comparing non-neurologic complications between the CAS and CEA groups revealed no significant difference between them (P = 0.485), nor was there a significant difference when stroke rates were compared (P = 0.174). The overall complication rate between the two also failed to reach statistical significance (P = 0.417). Logistic regression analysis revealed that neither age, sex, nor the presence of preoperative symptomatology significantly influenced the occurrence of a perioperative neurologic event.

Late Outcomes

After the periprocedural 30-day period, the incidence of fatal and nonfatal stroke was 1.1% (2) among the stented group. One occurred in a patient who was on Coumadin for atrial fibrillation and suffered a fatal hemorrhagic stroke after a fall. A second patient suffered a fatal cerebrovascular accident 22 months after CAS. Overall, the late mortality rate was 4.0% (7). These deaths consisted of a death due to an indeterminate yet non-neurologic cause at 9 months, a fatal MI at 31 days, a fatal MI at 1 year, death secondary to pneumonia at 2 years after CAS, and the aforementioned fatalstrokes.

Recurrent stenoses occurred in 3 patients (1.7%) after CAS, all of which were women. One patient developed an in-stent stenosis at 18 months with peak systolic velocity (PSV) and end diastolic velocity (EDV) of 341/126 cm/s. A second patient developed symptomatic restenosis in a previous vein bypass graft at 9 months (PSV and EDV of 372/128 cm/s, midsegment). Both recurrences were treated with repeat balloon angioplasty alone and remain patent at least 12 months later. A third patient developed a symptomatic recurrent stenosis at 12 months (PSV and EDV of 613/312 cm/s) within a segment of a prior CEA not originally stented. This was managed by repeat angioplasty and proximal extension of the stented segment. It remains patent at 12-month follow-up. One additional patient had an asymptomatic occlusion of the carotid stent discovered during the 6-month surveillance carotid duplex scan. Interestingly, this is the only patient who did not undergo post-stent angioplasty at the time of the procedure.

DISCUSSION

Historically, the primary treatment modality of severe occlusive extracranial carotid artery lesions has been CEA. This procedure has been substantiated by several multicenter, randomized, prospective trials, demonstrating its efficacy in a subset of symptomatic and asymptomatic patients (North American Symptomatic Carotid Endarterectomy Trial [NASCET],¹³ Asymptomatic Carotid Atherosclerosis Study [ACAS],¹⁴ European Carotid Surgery Trial,¹⁵ VA Symptomatic Trial,¹⁶ and Asymptomatic Carotid Surgery Trial¹⁷). However, technology continues to advance at a rapid pace, providing new therapeutic modalities for the treatment of stroke. Minimally invasive techniques have allowed the treatment of carotid plaques by using balloon angioplasty and stents. This new treatment strategy is one of the most exciting developments in the surgical treatment of stroke, but it must undergo the same scrutiny as CEA before it becomes widely practiced as a treatment option. Although alarming to surgeons, current evidence raises the specter of the end of CEA as the gold standard.¹⁸ Based on a multispecialty review, the general consensus of CAS to date is that it is currently appropriate treatment of high-risk patients at experienced centers but is not generally appropriate for low-risk patients.⁹ High-risk patients may include patients with multiple medical comorbidities, restenotic lesions, high and inaccessible carotid lesions, carotid stenosis in a radiated neck, or a previously operated neck. Additionally, concomitant use of mechanical cerebral protection devices is strongly advocated in conjunction with CAS. Multiple groups have demonstrated that cerebral protection devices—regardless of whether it is adistal filter, distal balloon occlusion, or flow-reversal system—prevent embolization during CAS and should be considered the standard of care when performing these procedures.^19,20

One of the first and largest randomized trials that evaluated the role of CAS was the Carotid and Vertebral Artery Transluminal Angioplasty Study (CAVATAS).²¹ This multicenter trial randomly assigned 504 patients to endovascular treatment (251 patients) versus CEA (253 patients). Only 26% of the endovascularly treated group were treated with a stent while the other 76% were treated with angioplasty alone. The stroke and death rate between the 2 groups within 30 days of treatment was not different: 10% in the endovascular group versus 9.9% in the CEA group. The investigators concluded that there was no difference in themajor risks of either treatment group. A major criticism of this study is the periprocedural complication rate of 9.9% in the CEA group, which is much higher than published reports for CEA. In addition, only a small portion of the endovascular group was treated with angioplasty and stenting. Several other early studies lacking brain protection demonstrated unacceptably high periprocedural neurologic complication rates. These are exemplified by the Leicester trial, which was prematurely terminated when, after enrolling 17 patients, 5 of the 7 patients treated with unprotected CAS developed a periprocedural neurologic event.²² This unfortunate study was followed by the WALLSTENT trial, which was stopped prematurely when the 30-day stroke and death rate of 12.1% for unprotected CAS was compared with a 4.5% rate in the CEA arm.²³

However, the more recent trials and registries utilizing cerebral protection have demonstrated a downward trend in adverse events. The Acculink for Revascularization of Carotids in High Risk patients (ARCHeR) enrolled patients in 3 different stages: 1) no cerebral protection; 2) cerebral protection; and 3) monorail systems with protection.²⁴ The 1-year total stroke rate was 4.4%, 5.8%, and 6.2% for ARCHeR stages 1, 2, and 3, respectively. The Medtronic AVE Self-Expandable Carotid Stent System with Distal Protection in the Treatment of Carotid Stenosis (MAVeRIC) demonstrated a 3.6% combined stroke rate for phases I and II.²⁵ The Boston Scientific trials—Boston Scientific: A Carotid Stenting Trial for High-Risk Surgical Patients (BEACH)²⁶ and Carotid Artery Revascularization Trial Using the Boston Scientific Filter Wire EX/EZ and the EndoTex Nex/Stent (CABERNET)¹¹—demonstrated 30-day major and minor stroke rates of 4.2% and 3.4%, respectively.

The Stenting and Angioplasty with Protection in Patients at High Risk for Endarterectomy (SAPPHIRE) has become the central trial supporting the efficacy of CAS with the use of cerebral protection devices, with reported embolic retrieval in 57–60% of cases.¹⁰ The early results of SAPPHIRE showed a 30-day combined death, stroke, and/or MI rate (including non-Q wave MI) of 5.8% in the CAS group versus 12.6% for CEA (P = 0.047). Although this was statistically different, the difference was primarily due to the inclusion of non-Q wave MIs. The 12-month results showed a continued benefit in the CAS group, with a major adverse event rate of 11.9% in the CAS group compared with 19.9% in CEA patients. Importantly, a statistically significant difference was again only seen when analyzing MI rates (CAS, 2.5% versus CAE, 7.9%; P = 0.04). This led the principle investigators of this trial to conclude that CAS with embolic protection is not inferior to CEA in high-risk surgical patients. Based on these results and those reported in trials and registries such as the Carotid Revascularization with Endarterectomy and Stenting Systems (CARESS) Trial, many specialists and companies will push CAS as an alternative for CEA.²⁷

Because of the intraoperative complications of seizure and asystolic arrest experienced in this review, we have continued to do all procedures in the operating room with anesthetic support. The seizures were found in patients with extensive intracranial and extracranial disease who likely suffered from global ischemia with the occlusive catheter or stent delivery systems. Bradycardia is a known consequence of carotid bulb manipulation and can progress to asystole if untreated. During CAS, the angioplasty has a similar effect and is best managed by the prophylactic administration of intravenous atropine, particularly for de novo lesions. This is now routinely employed in our cases.

CONCLUSIONS

Overall, when comparing the results of this review with NASCET and ACAS, the rate of stroke and death are comparable. NASCET demonstrated a 30-day major stroke and death rate of 2.1%, while ACAS demonstrated a rate of 2.3% over the same time period.^13,14 The current review notes a 1.1% major stroke and death rate among the CAS group and 0.3% with CEA. Interestingly, this number is surprising given the previously published 1.2% risk of stroke during cerebral angiography. There are limitations to this study. The small sample size may limit the ability to detect subtle trends in a group or differences between the groups. Not every patient was evaluated in the postoperative period by a neurologist. However, the investigating group did document a precise neurologic examination postoperatively and on all subsequent visits. It is unlikely that a major neurologic event was missed.

Carotid in-stent restenosis is another critical concern, which does not seem to mirror the experience of coronary interventions. In this study, we observed 3 cases of restenosis after CAS, all of which occurred in women treated for recurrent stenosis following CEA. Our restenosis rate of 1.7% corroborates the midterm experience of others.²⁸ Overall, the results of this study demonstrate that carotid artery angioplasty and stenting using cerebral protection can be performed safely in the hands of endovascularly trained surgeons, with results comparable to CEA. CAS has opened the door for a number of specialties to treat carotid artery disease. Surgeons (vascular surgeons in particular) must gain these advanced catheter-based skills if they are intent on treating carotid disease in the future.

Discussions

Dr. Anthony D. Whittemore (Boston, Massachusetts): There is no question with the addition of both routine stenting and cerebral protection devices, percutaneous intervention for carotid disease has clearly been upregulated with results comparable to conventional endarterectomy, and you have shown this very nicely. This is an expansion of a series that this group has previously published and it is gratifying to see that the results have held up. The manuscript raises a number of questions, but I have 3: Who are the right patients? Who are the right physicians? And who pays for it?

First, who are the right patients? How do we select the patients that will benefit most from minimally invasive intervention? You mention the population at high risk for CEA. Many of us have results that will contest the assumption that there are such patients at high risk for endarterectomy. In fact, high-risk patients in many series do just as well as routine patients with conventional endarterectomy. But be that as it may, you have defined high-risk patients as those who have contralateral occlusion, previous neck irradiation or surgery or severe comorbidities. If I understood your manuscript correctly, only a third of your patients fell into that category, the others did not. So how do you recommend that we outside the confines of a trial select patients appropriately for percutaneous intervention? How often is this driven by patient preference, do you think, thanks to direct consumer advertising?

Who are the right physicians? We have neuroradiologists, neurosurgeons, neurologists, interventional radiologists, cardiologists, vascular surgeons, probably the chairman of the board before too long, all inserting carotid stents. How do we credential these individuals? How do we hold all the disciplines involved to the same standards of care? Does Northwestern have a hospital-driven policy with appropriate credentialing standards so they are uniform, or does each specialty apply according to their own societies or local mores? How do you suggest that we regulate this in a way that makes sense for patient safety?

And then finally, who pays for this? Have you hugged your chief financial officer today?

Dr. Mark K. Eskandari (Chicago, Illinois): I will start with the first question, how do you select the patients? Currently, carotid angioplasty and stenting only represents about a third of all the patients that we treat. For otherwise healthy individuals, I still recommend carotid endarterectomy. Frequently the patients that I would recommend angioplasty and stenting are those individuals with recurrent stenosis, because the risk of distal embolization is significantly lower. Other patients that I think would be better suited for angioplasty and stenting are these with prior neck irradiation, or neck surgery, a laryngectomy, and/or a tracheostomy. There is no question that endarterectomy still has very good results in the hands of experienced surgeons. I think stenting will represent a subset of all the patients that we treat. And I think to hold onto those patients, we need to be proficient in doing this procedure.

With regard to credentialing and who are the physicians that should be doing this. There are a number of specialists that are involved in carotid stenting; one group that I find very fascinating is interventional neurologists. Historically surgeons have been intimately involved in the management of these patients, understand the natural history and follow-up for these patients, and are best suited to treat these individuals. With the credentialing, there are a number of groups that have rapidly tried to generate consensus papers from their own society organizations delineating what are the guidelines that are necessary to do carotid stenting. Unfortunately, there is no uniform standard.

At Northwestern we do have a credentialing program and a quality management program. In our group, 4 of us perform carotid stenting. Originally it was myself and Dr. Matsumura. We have subsequently taught 2 others in our group. My impression is that they begin to feel more comfortable after they have done roughly 25 cases.

With regard to costs, the way CMS reads right now is that although it is FDA approved they will only reimburse for symptomatic high risk patients. The other category of individuals are those individuals that are involved in an IDE trial.

Dr. John E. Connolly (Irvine, California): As I understand FDA approval, stenting currently should be limited to poor risk, symptomatic patients using mechanical cerebral protection. Can you explain why the majority of your procedures were in asymptomatic patients?

The indications for 53 of your patients, previous neck irradiation, recurrent stenosis, fibromuscular dysplasia, and contralateral carotid occlusion, I believe are valid. Are we to understand that the other 123 were patients with cardiac disease, which puts them in the so-called high risk category for endarterectomy?

Those of us who employ neck block for endarterectomy have enjoyed a significant reduction in cardiac problems compared to our own results under general anesthesia, causing us not to eliminate the so-called high risk patients for endarterectomy which is being used as a principal indication for stenting currently. And I have had a number of patients referred to me where an anesthesiologist would not put the patient to sleep and we were able to do the operation safely and successfully under regional neck block. Thus when comparing stenting risk to that of endarterectomy, I think it is only reasonable to use awake results rather than those under general anesthesia. The Sapphire study also wrongly used general anesthesia endarterectomy results for comparison with stenting results.

I have a couple of questions. You list retroperitoneal bleeds and femoral pseudoaneurysms as complications. Are they seen with the same frequency or more so by nonsurgeons doing stenting? Were any of your patients excluded from stenting because of contraindications to Plavix and aspirin? Finally, is it correct that the Canadian government will not pay for stenting because it is more expensive than open operation?

Apart from my above remarks, I agree with the authors that carotid stenting is here to stay and that vascular surgeons must learn the technique. The key is to be able to be the only physician who can offer both procedures. Otherwise, treatment by vascular surgeons may be lost. But more importantly, only those trained both in endarterectomy and stenting will be able to choose the safest and most effective procedure for the patient. I would speculate that this would be something like 85% endarterectomy and perhaps 15% stenting. But it will probably be many years before we can completely evaluate stenting, just as it has taken 50 years to get where we are now with safe endarterectomy.

Dr. Mark K. Eskandari (Chicago, Illinois): The first question I think is a very important one, and that is in regard to the large number of patients in the study that were asymptomatic. About two-thirds of the patients in this study were asymptomatic and a third were symptomatic. Most patients were enrolled in a trial or registry. A subset of patients classified as high risk had prior approval from their insurance company prior to stenting.

In regard to the incidence of retroperitoneal bleeding, it is comparable to other percutaneous interventions across specialties.

With regard to the costs in Canada, I can say that the cost of angioplasty and stenting is certainly more than it is for endarterectomy. The devices are rather costly. Each stent is about $1,200. A cerebral protection system is about $1,800. So when you look at the costs, it really is a losing battle compared to endarterectomy.

Carotid endarterectomy at our institution is primarily done under general anesthesia. I was trained in an era when I did most of my endarterectomy under general anesthesia and that has been my preference. I don’t have much in the way of experience with local blocks and can’t specifically comment.

Then the last question was with regard to the high risk patients. The severe comorbid conditions were either patients with underlying severe congestive heart failure, coronary disease, aortic stenosis, and home oxygen dependent COPD.

Dr. Anthony J. Comerota (Toledo, Ohio): You may know that George Biasi and the Iccaros investigators addressed the issue of ultrasound plaque characteristics and complications of carotid angioplasty and stenting. They found that the nonecholucent plaque defined by a gray-scale median score of less than 25 was associated with a 4 to 5 times increased risk of stroke of carotid angioplasty and stenting compared to a GSM score of greater than 25. Did you use either the GSM score or other elements of plaque characteristics to select your patients?

We know a number of reports have shown an unacceptably high stroke rate with carotid angioplasty and stenting in octogenarians. What is your approach to the octogenarian and is it different in symptomatic versus asymptomatic patients?

Dr. Mark K. Eskandari (Chicago, Illinois): The first question is with regard to the gray-scale median, which we have not incorporated in our practice. We make that judgment objectively based on the duplex ultrasonography. If the plaque looks subjectively to be a heavily echolucent, or soft, plaque then we favor endarterectomy.

With regard to patients over the age of 80, 1 patient out of 29 had a stroke.²⁹ That was 1 of the individuals in this cohort. The data from the CREST lead-in phase would suggest that stenting patients over the age of 80 should be tempered somewhat because of the high associated risk of stroke. For the most part, I will treat symptomatic patients over the age of 80, depending on the anatomy.

Dr. Gerald B. Zelenock (Royal Oak, Michigan): Excellent paper. The NASCET and ACAS studies were published 14 and 10 years ago respectively and planning and patient accrual occurred even earlier. The surgical therapy has evolved but so has the medical therapy, are the results from NASCET and ACAS the right comparison group? In other words, should we be doing a study to see whether either procedure is indicated in asymptomatic patients given that the use of statins, beta blockers and other drugs have probably changed the natural history of the asymptomatic patient treated medically?

My second question is: You reported a 2.2% stoke and death rate for stenting and 0.9% for operation (carotid endarterectomy). Although those did not achieve statistical significance, the n (number of patients) was relatively small at 350 patients. It seems that a 2.5-fold increase in death and mortality would be significant with a slightly larger patient sample. Have you done a power analysis to see how many more patients you need before you achieve statistical significance?

Dr. Mark K. Eskandari (Chicago, Illinois): The first question was in regard to the current medical treatment. The only data that we have that we can reliably look at right now is the data from the ACST which utilized lipid-lowering agents. This is a relevant question. The trial that is ongoing now is the CREST trial, which is stenting versus endarterectomy. There are many groups who feel that a medical arm is also necessary to answer the question adequately.

The second question was with regard to a power analysis. We have not done a power analysis. But I would agree with you that if you look at the numbers, our cohort is relatively small, making it hard to make a clear determination of what the stroke/death risk is.

Dr. Gregorio A. Sicard (St. Louis, Missouri): I think it is becoming clear that cerebral protection devices are going to be indicated and necessary for the treatment of carotid disease with stents. I noticed an uneven distribution in the cerebral protection devices used. Were there any anatomic criteria that led you to select a basket versus a balloon protection device? In 10% of your patients you did not use a protection device. What were the specific indications that led you not to use a cerebral protection device?

The second question relates to training in this procedure. As we look at safety and good outcomes, hands-on training of vascular surgeons already in practice becomes a logistical problem. How do you propose to train these surgeons that are not as skilled as your group? Do you think it is the role of simulators to act as the initial step in the training of surgeons in this new technique?

Dr. Mark K. Eskandari (Chicago, Illinois): There are training programs that are sponsored by corporations, both Cordis and Guidant. These training programs include online didactic, simulator training, case-based review, and then proctor cases. I think simulator training does play a role for carotid stenting. However, this is a procedure that requires some basic interventional skills. You can’t go from an aortic stent graft to carotid stenting.

The other question was the selection of the cerebral protection system. A lot of that is based on the anatomy. The filter baskets in general have a larger crossing profile, are somewhat more rigid. So for lesions that are somewhat tortuous or severely stenotic I have elected to use the distal balloon occlusion system, which is more flexible and has a lower crossing profile.

In the 10% of patients that did not have cerebral protection, these were either individuals early on in our experience in which we did not have protection systems available to us or these were at least cases where I was unable to pass a cerebral protection system and elected to proceed without it. I would strongly encourage those of us who decide to embark on this that cerebral protection be utilized during these cases.

Dr. Juan C. Parodi (St. Louis, Missouri): I have only 1 question in relation to vascular procedures. We have conducted a similar study with Dr. Kine in St. Louis, Missouri, and we have patients with strokes and we attempt aggressive procedure very successfully. Have you tried to recover those patients using microcatheters or any other means?

Dr. Mark K. Eskandari (Chicago, Illinois): We have not. I have looked to you, actually, for guidance on this with regard to neuro rescue because I think your group has probably had the most promising results. In the patients that we have had, there were only 2 major hemispheric strokes, the other ones were posterior strokes, and both of those individuals had a significant recuperation in their neurologic status relatively quickly so I elected not to proceed with neuro rescue. It may be something that is worth pursuing at some point, but there is really no good data right now, with the exception of some of the case reports.