It may sound pretentious, even a little arrogant, but as a vascular surgeon who has gained a great deal of experience and confidence with both endarterectomy (CEA) and stenting (CAS) over the years, I feel uniquely qualified to express strong views on this, the most important vascular topic of the day. I count myself among a group of ‘senior’ endovascular specialists whose interventional journey began in the 1980s. As such, we had the opportunity to witness and actively participate in a number of significant developments with new technologies and techniques. Some of these, in fact, resulted in “game-changing” evolutions, and yet, nothing even remotely approximated the “CAS storm” that’s ravaging every vascular community in the U.S. at the present time.
Why then are we all so excited, even troubled about CAS? What's so special about carotid intervention?
There are several things:
• Anatomy: It is a bifurcation, exposed to external compression and subjected to significant mobility. Additionally, there is the need for ballooning and stenting across 3 contiguous segments [common carotid artery (CCA), bulb, and internal carotid artery (ICA)] that tend to have major diameter mismatches.
• Access: To get to the above anatomy, devices have to traverse the aortic arch and the proximal common carotid artery, both sites of frequent anatomical challenges.
• The lesion itself: Carotid plaques tend to be complex, calcified, and eccentric. Vascular surgeons’ initial reluctance to consider CAS as a viable carotid revascularization strategy related precisely to their real-life knowledge of such “ugly lesions,” displayed in full upon scissor or knife splitting during open surgery.
• The brain, lying just a few centimeters beyond the tip of our devices, may also have a lot to do with it. While it has (thankfully) proven far more resilient and forgiving than expected, most would agree that the potential for a stroke is an ever-present fear, far more powerful than the thought of a cold foot or blue toe.
• The anticipated “players” and their diverse specialty background is another influential factor. In particular, there is continuing concern about two specific issues:
1) The anticipated large number of interventional cardiologists entering the CAS arena, a brand-new endeavor for them as management of carotid artery disease was never before a component of cardiology training or practice.
2) Vascular surgeons will undoubtedly do what it takes to be active participants in the CAS revolution as they — literally — cannot afford not to! But, in general, surgeons still lack the kind of refined endovascular and imaging skills felt to be crucial for optimal CAS performance.
• Lastly, I would also like to suggest that much of the ‘noise’ and controversy relate to the notion that CAS is rapidly emerging (at this time) as a ‘replacement’ for CEA — arguably, the best and most scientifically validated operation in all of vascular surgery, and nothing short of an icon for evidence-based medicine.
Some would have us believe that CAS evolved largely as an industry-driven effort propelled by a bunch of “procedure-hungry” interventional cardiologists. On the other end of the spectrum, many others would maintain that CAS developed out of the need to address a real clinical issue, that of patients at high risk for CEA. Whether this makes up 20% of CEA caseloads, much more or much less, there is little question that these situations indeed exist and that surgeons are reluctant (or outright unwilling) to operate on many such patients, especially those with hostile neck anatomy and restenosis.
In closing, these are the CAS facts as we know them today (December 2004):
• FDA approval of the first CAS system (Guidant) was announced on Aug. 31, 2004 — high-risk only
• CMS reimbursement approval (high-risk) is anticipated in 2005 (March/April at the earliest)
• Both the FDA and CMS have announced unequivocally that off-label use of devices in the carotid territory will not be tolerated. (If you will, the beginning of a new era is upon us.)
• Additional CAS systems are expected to be cleared and launched in 2005
• Embolic protection devices will soon be approved using a 510k pathway
• CAS indication for low-risk patients remains unstudied
What’s the future of CAS, and how much of the “CEA market” will it overtake?
While estimates of “>50%” and “up to 80%” are being discussed, I think it is too early for realistic predictions to be made. We still do not have definitive information on the performance of CAS in the treatment of several important patient cohorts. Those (and other) uncertainties notwithstanding, CAS is expected by many (myself included) to become the most important treatment modality for carotid revascularization and stroke prevention in the years to come. Training and credentialing issues are huge, and likely to become the most significant limiting factor in the foreseeable future. It is incumbent upon all major stake-holders (industry, major vascular societies, leading investigators, and local hospitals) to do what is right and necessary for CAS to be introduced as a safe and viable treatment option for patients with severe carotid artery stenosis.
Frank J. Criado, Editor-in-Chief
Director, Center for Vascular Intervention; Chief, Division of Vascular Surgery; Union Memorial Hospital/MedStar Health, Baltimore, MD; frank.criado@medstar.net
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