争鸣：治疗颈动脉狭窄——PCI还是外科手术？

Point-Counterpoint: Carotid Artery Stenosis–PCI or Surgery?               

Point-Counterpoint: Carotid Artery Stenosis–PCI or Surgery?      
 
William A. Gray, MD, Director, Endovascular Services Center for Interventional Vascular Therapy, Columbia University Medical Center, New York, N.Y.

Richard Cambria, MD, Chief, Vascular and Endovascular Surgery, Massachusetts General Hospital, Boston, Mass.

Do we have enough evidence to prove the safety/efficacy of carotid artery stenting (CAS) vs. carotid endarterectomy (CEA)?

Gray: We have very strong proof that carotid stenting is at least as good as, or better than, carotid endarterectomy in the high-surgical-risk patient. Moreover, there are data currently in press showing that in postmarket surveillance registries with reports on approximately 6,000 patients, carotid stenting in the high-risk population has achieved the American Heart Association (AHA) 3% guideline for stroke and death at 30 days in asymptomatic patients. In that regard, carotid stenting actually accomplishes something endarterectomy has never done, which is, in this population, to meet or exceed the AHA standard in high-surgical-risk patients.

In the standard-surgical-risk population, the safety and efficacy of carotid stenting compared with endarterectomy are yet to be determined. The studies are still in process, specifically CREST, which was recently completed and should provide data from 2,500 patients (normal-surgical-risk symptomatic and asymptomatic) by the end of 2009. Also ACT I, which is investigating asymptomatic, standard-surgical-risk patients randomized to surgery or stenting, currently is enrolling and is approximately one-third of the way into its 1,800-patient enrollment.

Cambria: There is level 1 evidence supporting CEA as the optimal choice of therapy in symptomatic and asymptomatic patients who require carotid intervention. There also is considerable evidence that CAS has produced unacceptable outcomes in many patient subgroups (eg, octogenarians and symptomatic patients, in particular, patients who have recently become symptomatic). Furthermore, many anatomic factors that are associated with increased risk in CAS intervention are not relevant with CEA.

Many of the studies that purport to show "favorable" results with CAS (ARCHER, BEACH) are simply not valid. This derives from the fact that the protocols (registries for the most part) that gathered historical controls for CEA in high-risk patients included many patients who were undergoing combined CEA/CABG. The stroke/death rates in these "control" populations (14% in ARCHER) simply do not reflect the rates found in contemporary studies of CEA, and no practicing surgeon would accept this level of risk in any patient subset. The fact is that significant CAS data reveal complication rates distinctly inferior to what is achieved with CEA in most environments.

Patient selection: What are the characteristics that should drive the choice between CAS and CEA?

Gray: First, the decision has to be made as to whether the patient requires any revascularization. In patients who are asymptomatic, who are very elderly, and who have a limited life expectancy, revascularization is probably not necessary and may not be appropriate. Alternately, patients who are symptomatic and patients who are asymptomatic with a reasonable life expectancy (>5 years) should be considered for revascularization. The question then becomes, is the patient at high surgical risk? Is there some anatomic or medical comorbidity that puts them at increased risk for endarterectomy? If there is, the patient should be considered for stenting. If there is not, the patient should be considered for a randomized trial between the two modalities.

Surgery can be performed on virtually anyone, but at what risk? There clearly are factors that affect the outcomes of patients undergoing CEA. Studies demonstrating the effectiveness of CAS have generally followed the same inclusion criteria, which are:

Severe coronary artery disease in more than two vessels.
Severe heart failure or left ventricular dysfunction.
Severe chronic obstructive pulmonary disease (COPD) with a FEV1 ,30% predicted.
Severe renal disease.
Age older than 80.
Previous endarterectomy and restenosis.
Radical neck dissections.
Tracheostomy stoma.
High lesions at or above C2.
Radiation-induced carotid stenosis.
Contralateral laryngeal nerve palsy.

Cambria: The only characteristics that should guide a choice towards CAS are circumstances of the neck where CEA would be unfavorable (ie, so-called anatomic high risk). These patients, however, are in fact rare when such decisions are made by competent surgeons. For instance, in the recent appeal to the Centers for Medicare and Medicaid Services to extend coverage to anatomic high-risk cases, our cardiology and neuroradiology colleagues attempted to draw up such a list. Included was a condition called "immobile neck." After 2,000 CEA procedures, I have yet to experience this phenomenon. On the other hand, recurrent stenosis after CEA is a reasonable anatomic circumstance to consider CAS when the lesion involves intimal hyperplasia, but not late, extensive, recurrent atherosclerotic lesions. 

Indications: In patients with symptomatic carotid stenosis, which modality is more appropriate?

Gray: The decision has to do with the severity of the lesion. In the United States, most patients with a lesion ,80% would not be offered revascularization because the risk of stroke does not exceed the risk of revascularization at one year. However, at .80%, the risk of stroke goes up without intervention, potentially to 3% or more per year.

I look at stenting and surgery as very complementary procedures and not mutually exclusive, the appropriate analogy being coronary intervention and coronary bypass surgery. For example, there is a patient population, which, although relatively small, is not appropriate for stenting. These patients have excessive tortuosity of the vessels and excessive calcification. Generally, they are not going to be well suited for stenting and better suited for surgery.

Cambria: In asymptomatic patients, CEA is the best choice in virtually all patients. Show me a patient with asymptomatic stenosis who cannot have a CEA, and I will show you a patient who does not need a carotid intervention.

What role should physician experience play in deciding between CAS vs. CEA?

Gray: What the data have shown is that since approval of these devices in 2004, physician experience is probably one of, if not the most, important factor influencing patient outcomes. I say that because we have seen a significant improvement in outcomes over the course of three or four years. This, I believe, is primarily related to patient selection, which goes hand-in-hand with physician experience.

Cambria: Guidelines for operator experience should be rigid for either intervention.

Within five years, will the predominant method for treating carotid atherosclerosis be CAS or CEA?

Gray: Assuming that CREST shows a reasonable equivalence between the two, I think we are going to see a gradual shift to stenting over the next five to 10 years. Lacking a safety or efficacy differential, most patients prefer a nonsurgical approach.

Cambria: CEA is the preferred treatment and will remain so for most patients unless CREST indicates otherwise. Recall that five years ago everyone said CEA was ready to die a rapid death. Then the data came along, and the fact is the evidence for CEA is better than the evidence for CAS.

Disclosures:

Dr. Gray reports no relevant conflicts of interest.
Dr. Cambria reports no relevant conflicts of interest.

 （source：www.tctmd.com）