Neurology India Medknow Publications on behalf of the Neurological Society of India ISSN: 0028-3886 EISSN: 1998-4022 Vol. 50, Num. s1, 2002, pp. S112-S114

Neurology India, Vol. 50, (Suppl. 1), Dec, 2002, pp. S112-S114

Carotid Endarterectomy Versus Angioplasty : A Vascular Surgeon's Perspective

R. Parakh

Departments of Peripheral Vascular and Endovascular Surgery, Sir Ganga Ram Hospital, New Delhi -110 060, India.
Correspondence to : Dr. R. Parakh, Department Peripheral, Vascular and Endovascular Surgery, Sir Ganga Ram, Hospital, New Delhi-110 060, India.

Code Number: ni02172

Summary

Carotid endarterectomy (CEA) is an established procedure for secondary prevention of stroke in symptomatic individuals with carotid artery stenosis of 70%-99%. The availability of cerebral angioplasty (CA) and stenting has provided another option for the management of symptomatic carotid artery stenosis, although procedural embolisation remains a significant risk. Despite the obvious advantages , such as avoidance of wound complications, cranial nerve injury and the potential for day care intervention. CA is a relatively new treatment modality and has not been subject to the same scrutiny as CEA. There is need for developing appropriate selection criteria for selecting patients for CA, based on properly conducted randomized trials.

Key words : Carotid endarterectomy, Angioplasty, Carotid stenting, Stroke.

Introduction

Carotid surgery as we know it today was developed in the 1950s. A number of different procedures were described for treating atheromatous stenosis of carotid arteries.¹ These included resection of the stenosis and replacement with a homograft or saphenous vein graft. However, in the sixties and seventies these procedures were largely abandoned and carotid endarterectomy (CEA) became the most frequently performed operation for prevention of stroke. Towards the end of the 1980s, considerable uncertainty arose concerning the value of carotid endarterectomy.² Improvement in medical management was set against considerable geographical variation in the number of carotid endarterectomies performed,³ and striking differences in the rates of postoperative disabling stroke and death.⁴ This led to large scale, randomized trials to examine the relationship between degree of carotid stenosis and medical or surgical treatment for both symptomatic and asymptomatic patients. So, while CEA was a frequently performed procedure for preventing ischaemic stroke in western countries for 45 years, it achieved level 1 evidence of benefit only in 1991.^5,6 There was strong evidence that CEA, when compared to medical treatment alone, was significantly more effective in preventing strokes in patients with symptomatic internal carotid artery stenosis of 70% to 99%. Appropriate symptoms are amaurosis fugax, retinal infarction, carotid territory TIAs and non-disabling stroke. Asymptomatic patients with stenosis from 60-99% were also shown to benefit from carotid endarterectomy in a different study, but the benefit was too marginal for carotid surgery to be recommended for all asymptomatic patients in this group.⁷

Further data are required before firm conclusions can be drawn in a number of areas. No data from randomized trials exist to evaluate the role of carotid endarterectomy for other cerebral symptoms such as vertebrobasilar ischemia, non-hemispheric symptoms and eye signs other than amaurosis fugax. Existing data from trials of carotid endarterectomy for asymptomatic disease are too few to allow identification of high-risk subgroups where carotid surgery could be indicated. There are no data from randomized trials to support combined carotid endarterectomy and coronary artery bypass grafting for symptomatic cardiac and carotid disease. Metaanalysis suggests that a combined operation can be performed without excess risk.

Evolution of carotid angioplasty

The availability of cerebral angioplasty and stenting has provided new therapeutic options for the prevention of strokes. While the underlying rationale of carotid endarterectomy (CEA) is primarily the removal of the stenotic/ulcerated source of embolism, the rationale underlying carotid angioplasty (CA), is to dilate the stenosis and somehow favourably alter the physical and rheological characteristics of the plaque.⁸ Thus from the outset, there is a subtle difference in therapeutic approach between CEA and CA. Although procedural embolisation remains a significant risk,⁹ the latter is becoming popular because of potential advantages such as avoidance of wound complications, cranial nerve injury and the potential for day-care intervention. However, CA is a relatively new treatment modality and has not been subject to the same scrutiny as CEA. The current situation is therefore analogous to that which faced clinicians before the introduction of peripheral angioplasty in the 1970s and coronary angioplasty in the 1980s. The latter has now assumed an accepted role in the management of patients with ischemic heart disease, albeit with occasional grumbles from cardiac surgeons. The internal carotid artery (ICA) has been one of the last major vessels to be considered for angioplasty, primarily because of concerns about the adverse effects of procedural embolisation. A number of authors have published their preliminary experience and the fears about embolisation appeared to be unfounded. In an overview of the published results in 123 patients, Brown observed that CA was associated with a procedural risk of <1%.¹⁰ These results thereafter became a catalyst for the rapid development and proliferation of CA. However, instead of developing a consensus as to how CEA and/or CA may benefit patients in the future, much of the current debate has focused on interdisciplinary 'turf wars' between vascular surgeons, Interventionists and later cardiologists. In the current era of evidencebased practice, vascular surgeons may be forgiven for criticizing the atmosphere surrounding the evolution of CA (which appears to be driven by industry and the media rather than by science), while interventionists perceive vascular surgeons to be protectionist and driven by dogma and surgical paranoia.

The Revolution

The current status of carotid endarterectomy has taken 44 years to achieve. There is little to indicate that this operation will change greatly in the future. Performing carotid endarterectomy under local anaesthesia may remove some of the risks of surgery, but as yet data does not exist to substantiate this claim.

By contrast, the endovascular management of carotid disease began in 1983 and has developed in earnest only over the last 4-5 years. The future is exciting. Pharmaceutical cover surrounding the procedure can be optimized. A great deal of time and money is currently being invested in cerebral protection systems designed to limit embolisation.

Systems designed to limit embolisation by filtration are already developed and are entering clinical trials. Dedicated stents with low profile delivery systems, small interstices, and a coating to limit embolisation and restenosis are being developed.

The Future

It is inevitable that CA with stenting will have a role in the management of selected patients with carotid artery disease but appropriate selection criteria will only ever evolve from properly conducted randomized trials where inclusion and exclusion criteria are clearly stipulated. Until this is done, the results will never be generalisable. The problem that remains is the ability to reliably predict the high risk carotid plaque. Amid the haste to pioneer aids and technological advancements to make both CEA and CA safer, it should not be forgotten that only high-risk patients require intervention. Surgeons and radiologists cannot justify intervening in low risk patients in order to ensure optimal procedural outcomes. In the future, it seems inevitable that both surgeons and interventionists will become subject to increased independent audit and accountability. Those who quote the results of other trials or centers to justify individual practice face the daunting prospect of medicolegal action. It also seems likely that the volume of symptomatic patients being referred for CEA or CA will be greatly reduced in the future, thereby paving the way for centralization of carotid surgery and/or angioplasty into larger centers. Such a trend would serve to optimize outcomes, training, multi-disciplinary team input, cost and audit/research. The question as to whether CA will be able to meet these increasing demands in the future remains to be seen.

At present there is no evidence that, even with future technological advances, CA will be any more generalisable or safer than CEA.

References

1. Dyken M : Carotid endarterectomy studies: a glimmering of science. Stroke 1986; 17 : 355-358.
2. Warlow C : Carotid endarterectomy: does it work? Stroke 1984; 15 : 1068-1076.
3. Chassin M, Brook R, Park R et al : Variations in the use of medical and surgical services by the Medicare population. N Eng J Med 1986; 314 : 285-290.
4. Winslow C, Solomon D, Chassin M et al : The appropriateness of carotid endarterectomy. N Eng J Med 1988; 318 : 721-726.
5. European Carotid Surgery Trialists Group. MRC European carotid surgery trial : Interim results for symptomatic patients with severe (70-99%) or with mild (0-29%) carotid stenosis. Lancet 1991; 337 : 1235-1243.
6. North American Symptomatic Carotid Endarterectomy Trial Collaborators. Beneficial effect of carotid endarterectomy in symptomatic patients with high-grade stenosis. N Eng J Med 1991; 325 : 445-453.
7. Executive committee for asymptomatic carotid atherosclerosis study. Endarterectomy for asymptomatic carotid artery stenosis. JAMA 1995; 273 : 1421-1428
8. Ferguson RDG, Ferguson JG, Lee LI : Endovascular revascularization therapy in cerebral athero-occlusive disease. Neurosurg Clin North Am 1994; 5 : 511-527.
9. Goldsmith MF. Cerebral percutaneous angioplasty in second year of trials. JAMA 1992; 268 : 3039-3040.
10. Brown MM : Balloon angioplasty for cerebrovascular disease. Neurol Res 1992; 14 (suppl); 159-163.

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