Carotid Stenting versus Carotid Endarterectomy: Evidence Basis and Cost Implications

Article Outline

• Abstract
• Introduction
• Materials and Methods
  • Cost-effectiveness model
  • Outcomes
  • Cost estimates
  • Scenario and sensitivity analyses
• Results
• Discussion
• Acknowledgements
• References
• Copyright

Abstract 

Objective

Carotid Angioplasty combined with Stenting (CAS) is increasingly performed because of its presumed benefits. A study was performed to identify key factors that determine the cost-effectiveness as compared to conventional carotid endarterectomy (CEA).

Methods

The incremental cost-effectiveness of CAS over CEA for different scenarios was estimated using a modeling approach. Treatment costs were based on actual costs of successful procedures whereas costs of complications were taken from the literature. Patient survival was modeled using the endarterectomy patients from the ECST trial.

Results

Procedural costs of CAS are higher than those of CEA, mainly as a result of the high material costs. Cost-effectiveness of CAS primarily depends on major stroke rates. One percent increase in the peri-operative major stroke rate causes a cost increase of €1 051 and a loss of 0.06 quality adjusted life years.

Conclusions

At present CAS is at best non-inferior to CEA in terms of clinical outcome. Cost savings due to shorter admission are offset by the high costs associated with catheter-based interventions. At present CAS should be restricted to controlled settings until clinical trials have shown a substantial clinical benefit.

Keywords: Carotid arteries, Angioplasty, Stenting, Surgery, Cost-effectiveness

Back to Article Outline

Introduction 

Stroke is among the most disabling chronic diseases and one of the major causes of death in the Western world. In the Netherlands, with a population of 16 million inhabitants, around 12 per 1000 inhabitants suffer a stroke. In 2005 over 10 000 people died as a result of stroke representing 7.6% of all deaths.¹ The benefit of carotid endarterectomy (CEA) over the best medical treatment has been clearly demonstrated in patients with symptomatic carotid stenosis.², ³ The risk of stroke or death for symptomatic patients with severe stenosis within 30 days of CEA was 6.8% in ECST and 5.8% in NASCET. Carotid angioplasty combined with stenting (CAS) is another treatment option.⁴, ⁵ Theoretical advantages of CAS include a reduced morbidity rate, reduced overall cost, shortened hospitalization, and improved long-term patency rates. These thus far unsubstantiated claims require vigorous scrutiny before implementing CAS as an acceptable alternative to CEA.

At present, clinical trial results are showing equal or inferior results in terms of technical success and clinical outcome of CAS compared to CEA. Moreover, two recent trials comparing CAS and CEA were stopped because of poor angioplasty results.⁶, ⁷ Another trial stopped after interim results failed to prove the non-inferiority of CAS over CEA.⁸

Limited data are available on the health economic impact of CAS. Inconsistent conclusions regarding the cost benefits or positive health effects of the stenting procedure have been reported.⁹, ¹⁰, ¹¹, ¹², ¹³, ¹⁴, ¹⁵, ¹⁶

To obtain a clear answer to these urgent questions regarding the merits of CAS, we developed a comprehensive Markov type decision model. Our goals were to exploit the currently available evidence and insights to evaluate the balance between cost and effects of CAS versus CEA, and to obtain insight in the main drivers of cost-effectiveness.

Back to Article Outline

Materials and Methods 

Cost-effectiveness model 

A simulation model previously developed to describe the course of symptomatic carotid artery stenosis was adapted to comprise CAS as a treatment option.¹⁷ Within this Markov model four different health states were defined, i.e., healthy (recently symptomatic), minor stroke, major stroke and death. Each individual starts off in the healthy recently symptomatic state and may transfer to one of the subsequent states. The impact of these transitions in terms of health effects is accounted for by means of utility scores. The actual utility values for the different health states were based on previous publications.¹⁸, ¹⁹ Multiplication of survival time with the pertaining utility yields an estimate of so called Quality Adjusted Life Years (QALYs). Long-term survival was modeled using the ECST trial data.

Outcomes 

Peri-operative survival after CEA was modeled using the ECST (>70% stenosis) and the Cochrane review data.³, ²⁰ For CAS the global survey by Wholey and the results from Cochrane review were used.⁵, ²⁰ Only studies that treated symptomatic patients were included from the Cochrane review. In absence of actual data or evidence with regard to long-term clinical outcome and re-intervention rates after CAS at the outset we conservatively assumed these would be similar regardless of the initial procedure.

Cost estimates 

Procedural costs of CAS and CEA were obtained by analyzing the resources used and operative procedures performed in the University Medical Center Utrecht (UMCU) and the St. Antonius Hospital, Nieuwegein, The Netherlands. Costs were calculated for procedures without complications and based on 26 procedures for CEA and 11 procedures for CAS. Costs of materials used for CAS were based on 27 procedures. CEA was performed under general anesthesia in an operating theatre with a staff of eight. Intracranial circulation was monitored intra-operatively using transcranial Doppler (TCD) and electroencephalography (EEG). On average, patients were discharged 4 days after surgery, with a total of 5 hospitalization days. CAS was performed in an angio-room with only six staff. During CAS use of cerebral protection was left at the discretion of the attending interventionist. Patients were discharged the day after the intervention, with a total of 2 hospitalization days. For both procedures recovery took place in a medium care unit.

Cost estimates associated with acute minor or major stroke and cost of hospital stay were based on available Dutch literature.²¹, ²² The follow-up costs of stroke patients (such as costs of rehabilitation, nursing home, physical therapy) were also estimated based on published data.²³, ²⁴, ²⁵ All costs used were adjusted to the 2003 price level using a health care price index published by Statistics Netherlands. Costs and health effects were discounted at an annual discount rate of 4%.²⁶

Scenario and sensitivity analyses 

To assess whether the balance between costs and effects of CAS compared to CEA would turn out differently with different assumptions, i.e., under different scenarios, we used complication rates from published case series (combined in the global CAS registry) and randomized controlled trials. In our analyses complication rates and procedural costs were varied and their impact on the cost-effectiveness evaluated. In the sensitivity analyses changes in costs and effects as a function of peri-operative complication and re-operation rates were assessed.

Back to Article Outline

Results 

Peri-operative complication rates for CEA and CAS including their 95% confidence intervals from both sources are shown in Fig. 1. Fig. 2 shows the cost breakdown for both CEA and CAS. Detailed information on the cost per procedure is provided in Table 1. A CAS procedure on average costs €1 488 more than a CEA procedure. A major part of the cost of the endarterectomy procedure is attributable to hospitalization. An average of 5.7 hospitalization days after CEA accounts for one third of the total procedural cost. The costs of the stenting procedure can for a major part be attributed to costs of materials used during the intervention. The stents, catheters, and cerebral protection device (CPD) account for two thirds of the total costs of the procedure. The CPD accounts for one fifth of the total CAS procedural costs.

• 
  • View Large Image
  • Download to PowerPoint

• Figure 1 

  Peri-operative incidence rates with 95% confidence intervals per clinical outcome and data source.

• 
  • View Large Image
  • Download to PowerPoint

• Figure 2 

  Cost breakdown of CAS and CEA.

Table 1. Cost breakdown of CAS and CEA

Cost category	Costs (€)
	CAS			CEA
Personnel (number of)	326		831
Radiology assistant (2)		86
TCD operator		30			53
Interventional radiologist (2)		164
Neurophysiologist		46			83
Nurse (2)					134
Anesthetist nurse					67
Anesthetist					165
Vascular surgeon (2)					330
Materials	3 088		453
Stent		1 132
Other materials		920
Protective device		1 029
Anesthesia		6			219
Materials used					234
Overheads	756		453
Investment and maintenance		124			125
Cleaning		2			9
Housing		33			105
Social affairs		14			36
Purchasing		182			27
Other overheads		400			150
Diagnostics	587		567
Laboratory		89			69
Cost duplex and MRA		498			498
Recovery and hospital stay	743		1 708
Recovery		213			315
Nursing		530			1 394
TOTAL COST	5 500		4 012

Using the peri-operative complication rates from Fig. 1 and data from Table 1, Table 2, the cost-effectiveness of CAS over CEA was calculated over a 10 year time period for both the Cochrane review results (Scenario 1) and for the ECST patients versus the Wholey global CAS registry (Scenario 2). The estimated cost-effectiveness for each scenario is marked in Fig. 3, together with a 95% confidence region surrounding the estimates.

Table 2. Main model parameters

Description	Units	Mean value
Complication rates
Probability of technical failure during CAS5	Probability	1.11%
Re-operation rate post CAS32	per year	0.68%
Re-operation rate post CEA3	per year	0.09%
Post operative major stroke rate3	per year	0.43%
Post operative minor stroke rate3	per year	0.66%
Myocardial infarction rate3	per year	1.59%
Survival parameters
Death hazard ratio given stroke3	-/-	2.07
Death hazard ratio given disabling stroke3	-/-	6.05
Death hazard ratio given myocardial infarction3	-/-	2.09
Death hazard ratio given myocardial infarction and stroke3	-/-	3.09
Probability of death within 6 months after peri-operative disabling stroke3	Probability	9.30%
Probability of death after disabling stroke3	Probability	30.8%
Probability of death after myocardial infarction3	Probability	22.6%
Cost parameters
Cost myocardial infarction33	€/Event	15 000
Cost acute major stroke22	€/Event	25 769
Cost major stoke follow up (1st 6 months)22	€/6 months	18 781
Cost major stoke follow up (after 6 months)21, 23, 24	€/6 months	8 017
Cost major stoke on death within 6 months22	€/Event	7 779
Cost minor stoke follow up (1st 6 months) 22	€/6 months	5 556
Cost minor stoke on death within 6 months22	€/Event	4 146
Utility parameters
Myocardial infarction18	QALYs per year	0.88
Minor stroke19	QALYs per year	0.65
Major stroke19	QALYs per year	0.15
Death	QALYs per year	0.00

• 
  • View Large Image
  • Download to PowerPoint

• Figure 3 

  Cost-effectiveness of different scenarios.

For each scenario the differences in costs are indicated on the vertical axis and the differences in QALYs on the horizontal axis. If the procedural costs for CAS become less, or the number of complications decrease, resulting in QALYs gained, the cost-effectiveness point estimate will move towards the lower right quadrant and the CAS procedure is to be preferred. Any point below the diagonal line indicating the cost-effectiveness (CE) threshold, i.e., the amount society would be willing to spend in order to gain one QALY, indicates that CAS compared to CEA is cost-effective and CAS is to be preferred (as indicated by the arrow). Conversely, any point above this line indicates that CAS is not cost-effective.

Uncertainty with respect to different model parameters on the cost-effectiveness outcome can be evaluated by means of simulation. The analyses show that even though the point estimate of Scenario 2 (Wholey versus ECST) indicates CAS to be cost-effective, there would still be a 6.7% chance that the parameter in fact lies above the cost-effectiveness threshold (Fig. 3). Notably, based on Scenario 1 (outcome of the Cochrane review) we estimated that there is a 0.3% chance that in fact CAS is cost-effective.

The results of the sensitivity analyses are shown in Table 3. Here the changes in costs and QALYs per percent change in peri-operative complication rate are presented. In assessing the impact of procedural costs, we particularly looked at the procedural costs for CAS by assuming that the use of a CPD would be optional, i.e., may or may not be used. Without use of a CPD, costs of the CAS procedure decrease by 20%. Leaving out the CPD would move all the estimates in Fig. 3 down €1 077 in the cost-effectiveness plane. The cost impact for TCD use was shown to be marginal. Clearly, peri-procedural major stroke and death rates after CAS were the major (clinical) contributors to the differences in costs and effects.

Table 3. Change in costs and effects per percent increase in complication or re-intervention rates

Back to Article Outline

Discussion 

Our analyses show that the costs associated with CAS are considerably higher than those of CEA. For CAS to become cost-effective there should be a clear clinical benefit over CEA. This benefit should both from a clinician's and a health economic point of view show up as a reduced number of major strokes or deaths, as these complications have the highest impact on health and cost. However, given the presently available evidence there is a considerable likelihood that CAS is not presently cost-effective.²⁰ Moreover, two European randomized clinical trials comparing the effectiveness of CAS to CEA were stopped early because of the high complication rates in the stenting arm.⁶, ⁷ The results of these trials are in marked contrast with the initial case series published, once again endorsing that one should be very careful with interpretation and drawing critical conclusions from the latter.

With regard to costs, the standard hospitalization was considered 5 days for CEA (including the intervention day) which was significantly longer compared with our CAS group (5 vs 2 days). This reflects the rather conservative practice in the Netherlands at the time of data collection (2003). Interestingly, several authors have reported on cost reducing measures for CEA by operating in a day care setting. Our current practice guidelines include a next-day discharge for both CEA and CAS patients. Also, reducing ICU cost and utilizing regional anesthesia are measures that have been proposed for cost reduction.²⁷, ²⁸, ²⁹ A reduction in hospitalization time by three days would reduce the cost of a CEA procedure by €740 (a decrease of 18% in procedural costs). Clearly, these cost-reductions for CEA would require further clinical benefits and reduction in material cost for CAS to become a cost-effective alternative to CEA: it would move both estimates shown in Fig. 3 up over a distance of €740 along the vertical axis. This would further reduce the likelihood of CAS being cost-effective.

The confidence intervals (CI) of the peri-operative major stroke rates (the complication with the highest impact on the cost-effectiveness outcome) from ECST are more than 4% (Fig. 1). Looking at the impact of this variability in terms of cost and effects (€4 200 and 0.24 QALY, four times the values shown in Table 3) it is clear that there is insufficient evidence at present to accurately estimate the incremental cost-effectiveness of CAS over CEA. However, even though the exact estimate is uncertain, Fig. 3 indicates that on basis of the trial data CAS is clearly not cost-effective. On the other hand, if complication rates could for example be proven to be as low as reported by Wholey, CAS could become a (cost-)effective alternative to CEA. However, we suggest interpreting this scenario with extreme caution as such results are contradicted with current trial evidence: the most recent results from the EVA-3S and SPACE trials (both included in the Cochrane review) point in quite the opposite direction.⁷, ⁸ Note also, that all results presented thus far pertain to short-term outcomes. Our simulation model showed a high sensitivity to post intervention complication rates, a topic that has so far received only limited attention when comparing the effectiveness of CAS with CEA.³⁰ The major randomized trials on carotid angioplasty are CAVATAS, EVA-3S, SPACE, CREST and ICSS (CAVATAS-2) will have to focus on this issue.³¹ It will, however, take years before the (long-term) results of these studies will become available.

To our knowledge, only few studies have investigated the cost differential between CEA and CAS (Table 4). Most studies are in line with our findings and indicate a higher cost associated with CAS.⁹, ¹², ¹⁴, ¹⁵, ¹⁶ In all of these studies the stent and CPD costs clearly surpassed the personnel and additional costs. With more competitive devices being approved for this condition, it may be that these high costs will to some extent decrease in the near future. We also identified, two studies that could not demonstrate a statistically significant difference in cost between CAS and CEA. Both studies did not include the routine use of distal CPD, however.¹⁰, ¹³ One study, by Gray et al. actually reported lower costs associated with CAS vs CEA.¹¹ This study also did not include the routine use of CPD. As shown in Table 4, most reports on cost-effectiveness of CAS were single center studies with small sample sizes. This and other drawbacks such as use of tariffs would appear to suggest that our study is the first to adequately analyze net costs using outcome data from the large randomized controlled trials on CAS versus CEA.

Table 4. Observational studies comparing costs of carotid angioplasty (and stenting) versus carotid endarterectomy

Author/year	Origin	Intervention (# patients)	Objective	Conclusion
Jordan 19989	Single center	CEA(130) vs PTA (109)	In-hospital costs	PTA higher costs
Brooks 200110	Single center	CEA (51) vs CAS (53)	In-hospital costs and follow-up (2 years)	CAS slightly higher costs
Gray 200211	Single center	CEA (136) vs CAS (136)	In-hospital costs and follow-up (2 years)	CEA higher costs
Kilaru 200312	Single center+Literature	CEA (447) vs Literature	In-hospital costs and follow-up	CAS higher costs
Ecker 200413	Single center	CEA (391) vs CAS (46)	In-hospital costs	No cost advantage for either procedure
Park 200614	Single center	CEA (48) vs CAS (46)	In-hospital costs	CAS higher costs
Pawaskar 200715	Single center	CEA (31) vs CAS (31)	In-hospital costs	CAS higher costs
Wolf 200716	Single center	CEA (30) vs CAS (30)	In-hospital costs	CAS higher costs

There are some limitations inherent to the present study. Ours is a modeling study, which as a result relies on several assumptions and model parameters that as such may give rise to discussion. We feel, however, that we have carefully presented and discussed these assumptions and, moreover, have evaluated the impact on the results of our analyses.

We believe our findings suggest that CAS should be considered experimental, especially as long-term safety and durability are yet another source of concern and uncertainty. Any difference in stroke incidence, either because of re-stenosis or re-intervention, will have a major impact on long-term procedural (cost-) effectiveness. Clinicians and policy makers will hopefully recognize their responsibility to keep enrolling patients in the ongoing trials and not to use CAS ‘off-label’.

In conclusion, at present CAS is at best non-inferior to CEA in terms of clinical outcome. The cost savings due to shorter admission are offset by the high costs associated with catheter-based interventions. CAS has to be advised against in routine practice for patients with severe symptomatic carotid artery stenosis and should be restricted to controlled settings until clinical trials have shown a substantial clinical benefit.

Back to Article Outline

Acknowledgements 

We thank B.C. Eikelboom for his support as a member of the steering group and B.A. van Hout for providing assistance with the development of the cost-effectiveness model.

We would like to thank the Netherlands Organization for Health Research and Development (ZonMw) for funding this research project.

Marc van Sambeek is on an advisory board for Medtronic, Martin Brown obtained research grants for CAVATAS from the European Union, Sanofi-Synthélabo, the Stroke Association and the Medical Research Council (UK). His chair in Stroke Medicine is supported by the Reta Lila Weston Trust for Medical Research.

Back to Article Outline

References 

1. Statistics Netherlands (CBS). Online health statistics. Available from: http://www.cbs.nl2006;
   • View In Article
2. Beneficial effect of carotid endarterectomy in symptomatic patients with high-grade carotid stenosis. North American Symptomatic Carotid Endarterectomy Trial Collaborators. N Engl J Med. 1991;7:445–453
   • View In Article
3. Randomised trial of endarterectomy for recently symptomatic carotid stenosis: final results of the MRC European Carotid Surgery Trial (ECST). Lancet. 1998;9113:1379–1387
   • View In Article
4. Endovascular versus surgical treatment in patients with carotid stenosis in the Carotid and Vertebral Artery Transluminal Angioplasty Study (CAVATAS): a randomised trial. Lancet. 2001;9270:1729–1737
   • View In Article
5. Wholey MH, Al Mubarek N, Wholey MH. Updated review of the global carotid artery stent registry. Catheter Cardiovasc Interv. 2003;2:259–266
   • View In Article
6. Naylor AR, Bolia A, Abbott RJ, Pye IF, Smith J, Lennard N, et al. Randomized study of carotid angioplasty and stenting versus carotid endarterectomy: a stopped trial. J Vasc Surg. 1998;2:326–334
   • View In Article
7. Mas JL, Chatellier G, Beyssen B, Branchereau A, Moulin T, Becquemin JP, et al. Endarterectomy versus stenting in patients with symptomatic severe carotid stenosis. N Engl J Med. 2006;16:1660–1671
   • View In Article
8. Ringleb PA, Allenberg J, Bruckmann H, Eckstein HH, Fraedrich G, Hartmann M, et al. 30 day results from the SPACE trial of stent-protected angioplasty versus carotid endarterectomy in symptomatic patients: a randomised non-inferiority trial. Lancet. 2006;9543:1239–1247
   • View In Article
9. Jordan WD, Roye GD, Fisher WS, Redden D, McDowell HA. A cost comparison of balloon angioplasty and stenting versus endarterectomy for the treatment of carotid artery stenosis. J Vasc Surg. 1998;1:16–22
   • View In Article
10. Brooks WH, McClure RR, Jones MR, Coleman TC, Breathitt L. Carotid angioplasty and stenting versus carotid endarterectomy: randomized trial in a community hospital. J Am Coll Cardiol. 2001;6:1589–1595
    • View In Article
11. Gray WA, White HJ, Barrett DM, Chandran G, Turner R, Reisman M. Carotid stenting and endarterectomy: a clinical and cost comparison of revascularization strategies. Stroke. 2002;4:1063–1070
    • View In Article
12. Kilaru S, Korn P, Kasirajan K, Lee TY, Beavers FP, Lyon RT, et al. Is carotid angioplasty and stenting more cost effective than carotid endarterectomy?. J Vasc Surg. 2003;2:331–339
    • View In Article
13. Ecker RD, Brown RD, Nichols DA, McClelland RL, Reinalda MS, Piepgras DG, et al. Cost of treating high-risk symptomatic carotid artery stenosis: stent insertion and angioplasty compared with endarterectomy. J Neurosurg. 2004;6:904–907
    • View In Article
14. Park B, Mavanur A, Dahn M, Menzoian J. Clinical outcomes and cost comparison of carotid artery angioplasty with stenting versus carotid endarterectomy. J Vasc Surg. 2006;2:270–276
    • View In Article
    • Abstract
    • Full Text
    • Full-Text PDF (1139 KB)
    • CrossRef
15. Pawaskar M, Satiani B, Balkrishnan R, Starr JE. Economic evaluation of carotid artery stenting versus carotid endarterectomy for the treatment of carotid artery stenosis. J Am Coll Surg. 2007;3:413–419
    • View In Article
16. Wolf O, Heider P, Weiss W, Hanke M, Reeps C, Mann U, et al. Analysis of cost-effectiveness. Comparison of carotid endarterectomy and carotid artery stenting in a university hospital. Gefasschirurgie. 2007;6:435–439
    • View In Article
17. Buskens E, Nederkoorn PJ, Buijs-Van Der Woude T, Mali WP, Kappelle LJ, Eikelboom BC, et al. Imaging of carotid arteries in symptomatic patients: cost-effectiveness of diagnostic strategies. Radiology. 2004;1:101–112
    • View In Article
18. Tsevat J, Goldman L, Soukup JR, Lamas GA, Connors KF, Chapin CC, et al. Stability of time-tradeoff utilities in survivors of myocardial infarction. Med Decis Making. 1993;2:161–165
    • View In Article
    • MEDLINE
    • CrossRef
19. Post PN, Stiggelbout AM, Wakker PP. The utility of health states after stroke: a systematic review of the literature. Stroke. 2001;6:1425–1429
    • View In Article
20. Ederle J, Featherstone RL, Brown MM. Percutaneous transluminal angioplasty and stenting for carotid artery stenosis. Cochrane Database Syst Rev. 2007;4:CD000515
    • View In Article
21. Bergman L, van der Meulen JH, Limburg M, Habbema JD. Costs of medical care after first-ever stroke in The Netherlands. Stroke. 1995;10:1830–1836
    • View In Article
22. Huijsman R, Klazinga NS, Scholte op Reimer WJM, Wijngaarden JDHv, Exel NJAv, Putte-Boon Cv, et al. EDISSE, Evaluation Dutch Integrated Stroke Service Experiments, 2001.
    • View In Article
23. de Haan R, Limburg M, van der MJ, van den Bos GA. Use of health care services after stroke. Qual Health Care. 1993;4:222–227
    • View In Article
24. Schuling J, Groenier KH, Meyboom-de Jong B. Home treatment of patients with cerebrovascular accidents, Ned Tijdschr Geneeskd. 1993;38:1918–1922
    • View In Article
25. Oostenbrink JB, Koopmanschap MA, Rutten FF. Standardisation of costs: the Dutch manual for costing in economic evaluations. Pharmacoeconomics. 2002;7:443–454
    • View In Article
26. CVZ . Guideline for pharmaco-economic research. [Richtlijn voor farmaco-economisch onderzoek] Amstelveen: CVZ; 1999;
    • View In Article
27. Hodby D. Dollars and sense: the economics and outcomes of patients undergoing carotid endarterectomy at Royal Adelaide Hospital. J Vasc Nurs. 2002;1:6–11
    • View In Article
28. Hobart DC, Nicholas GG, Reed JF, Nastasee SA. Carotid endarterectomy outcomes research: reduced resource utilization using a clinical protocol. Cardiovasc Surg. 2000;6:446–451
    • View In Article
    • MEDLINE
    • CrossRef
29. Back MR, Harward TR, Huber TS, Carlton LM, Flynn TC, Seeger JM. Improving the cost-effectiveness of carotid endarterectomy. J Vasc Surg. 1997;3:456–462
    • View In Article
    • Abstract
    • Full-Text PDF (435 KB)
    • CrossRef
30. Janssen MP, Buskens E. Optimal treatment for carotid artery stenosis. Utrecht: Julius Center, UMC Utrecht; 2004 May 6;Report No.: ZONMW 945-01-026
    • View In Article
31. Strokecenter. Current stroke trials. Available from: http://www.strokecenter.org/trials/browse.aspx?type=32006;
    • View In Article
32. Bosiers M, Peeters P, Deloose K, Verbist J, Sievert H, Sugita J, et al. Does carotid artery stenting work on the long run: 5-year results in high-volume centers (ELOCAS Registry). J Cardiovasc Surg (Torino). 2005;3:241–247
    • View In Article
33. Legrand VM, Serruys PW, Unger F, van Hout BA, Vrolix MC, Fransen GM, et al. Three-year outcome after coronary stenting versus bypass surgery for the treatment of multivessel disease. Circulation. 2004;9:1114–1120
    • View In Article