March 3, 2010
Two randomized trials have recently reported their results comparing carotid artery stenting versus surgery. There have been some news reports in this regard, based on limited information. We are particularly excited about the emergence of carotid stenting, a technology that was readily embraced by our specialty. SVS is in a unique position to comment on this topic given the fact that ours is the only specialty involved in the treatment of carotid disease using all three modalities; 1) best medical therapy, 2) carotid endarterectomy (CEA), and 3) carotid stenting (CAS). This comment provides our preliminary interpretation of the current evidence surrounding safety, efficacy, and durability of CAS in light of the new evidence available. We will be framing a more detailed report in the coming days. Please note that until a communication is forthcoming from the FDA and CMS, the approved indications for CAS remain unchanged. We will keep you informed.
The Carotid Revascularization, Endarterectomy versus Stenting Trial reported its results at a presentation on Feb. 26, 2010. It randomly assigned 2,502 patients with symptomatic (≥50% stenosis by angiography, ≥70% by ultrasound) or asymptomatic (≥60% stenosis by angiography, ≥70% by ultrasound) to either CAS or CEA. Centers from 108 US and 9 Canadian sites enrolled 47% asymptomatic and 53% symptomatic patients. The combined rate of periprocedural stroke death, myocardial infarction, and post-procedural stroke was not significantly different between CAS and CEA (7.2% and 6.8% respectively). Patients <70 years did better with CAS and those ≥70 years old had a better combined outcome with CEA. However, periprocedural stroke occurred more frequently after CAS (4.1% vs 2.3% after CEA); while myocardial infarction occurred more frequently after CEA (1.1% vs 2.3% after CAS). Patients suffering a stroke after revascularization recorded a much worse quality of life compared to those that had a myocardial infarction.
The International Carotid Stenting Study (ICSS) published its results comparing CAS to CEA also on Feb 26, 2010. This randomized study enrolled 1,713 patients with symptomatic stenosis from 50 academic centers in Europe, Australia, New Zealand, and Canada. The combined rate of periprocedural stroke, death, or myocardial infarction occurred more frequently after CAS compared to CEA (8•5% versus 5•2%). Similarly, periprocedural stroke occurred more frequently after CAS (7.7% versus 4.1% for CEA).
There are some important similarities and differences between these two trials.
Both these trials demonstrate a major improvement in the results of CEA over previously reported randomized trials. The stroke and death rate for symptomatic patients undergoing CEA in CREST is almost half of what was reported in NASCET; and in ICSS is almost half of what was reported in ECST.
CREST allowed the use of only one stent device (Acculink/Accunet, Abbott Vascular) and had a prolonged credentialing process; both of which probably improved operator familiarity and performance for CAS. ICSS allowed the use of all stent devices approved in the participating countries (about 9 different stents) and did not include mandatory adjudicated credentialing procedures. CREST therefore reflects the best possible scenario with CAS and CEA; while ICSS reflects a more “real world” scenario.
Strokes after CAS have occurred at a rate almost twice that of CEA fairly consistently across multiple randomized trials, registries, and Medicare databases. That relationship has been maintained in CREST and ICSS also. We do not see any major technical or technological changes in CAS in the immediate future that may change this relationship.
Myocardial infarction is higher after CEA compared to CAS in CREST; though these patients do not have as adverse an impact on their quality of life as patients with a periprocedural stroke. ICSS and other European randomized trials have not seen a difference in MI between the two procedures consistently. Cardioprotective pharmacotherapy was not recorded in either trial and periprocedural dual antiplatelet therapy is not traditionally used for CEA. These and other areas will require further investigation.
CREST reported on a mean follow-up of about 2.5 years while the follow-up for ICSS was 4 months. We will have to wait longer to obtain reliable information on recurrence/restenosis rates and other long-term durability parameters.
The effect of age seen in CREST is based on the composite outcome of stroke, myocardial infarction and death. It remains to be seen how the information changes when stroke and myocardial infarction are analyzed separately; and when symptomatic and asymptomatic patients are reviewed separately. It is likely that age is acting as a surrogate marker for arterial tortuosity and/or calcification, thereby making CAS more hazardous. In any event, it is unlikely that assigning an artificial numeric age threshold to determine which procedure to offer a patient is overly simplistic and a disservice to patients.
Therefore, beyond the “headline” news of equivalence, there are several fine points to the results that must be appreciated and incorporated into our practices. The absence of a clear “winner” implies that recommendations for an individual patient must be made after careful consideration of all the information. This will require balancing risks for different morbidities impartially. It is an opportunity to highlight the role of vascular surgeons who have had the longest tradition in the management of carotid disease. Since we are well-trained to provide medical, surgical, or endovascular treatment for carotid stenosis; we are best equipped to provide the most impartial advice to our patients.
We believe that both CAS and CEA will remain useful tools for preventing stroke. As a society, we have encouraged all members to become conversant with all three modalities of treating carotid stenosis. We are reassured that our specialty has embraced the new technology while avoiding being blinded by hyperbole. Our excellent cognitive and technical skills with CAS and with CEA are the biggest resource for our patients.
Updated August 2010