Carotid Artery Revascularization in 2007
Will we still be performing surgery 5 years from now?
Managing carotid artery disease (CAD) may be the most significant activity in a vascular surgeon’s practice. Carotid endarterectomy (CEA) offers effective surgical treatment and has become the gold standard.
CEA’s rise to stardom is based on solid evidence from randomized clinical trials demonstrating this procedure’s superiority over best medical treatment in the prevention of stroke caused by internal carotid artery (ICA) stenosis. CEA is perhaps the most scientifically validated procedure in all of vascular surgery and is the one performed most frequently. Today, approximately 250,000 such surgeries take place annually in the US. In this context, it is somewhat perplexing that so much effort has been put into potentially replacing CEA with carotid artery stenting (CAS), a far less-proven intervention. How has this come about?
WHEN CEA MAY NOT BE BEST
In my view, two distinct issues have principally fueled current developments in nonsurgical carotid artery revascularization: the debate over a high-risk subset of patients and the growing popularity of catheter-based procedures.
The High-Risk Cohort
Although most patients with severe ICA stenosis can be treated with CEA, there is undoubtedly a high-risk subset for whom surgery may be difficult, dangerous, or occasionally infeasible. Neck or lesion-related anatomical factors account for the majority of these patients (Figures 1 and 2). In addition, severe medical comorbidities (mainly cardiac) can sometimes represent contra-indications to carotid artery surgery. Surgeons and interventionalists cannot agree on the size of this high-risk cohort, and the controversy is likely to continue for some time. The disagreement extends to the very nature of these factors. For instance, few if any vascular surgeons would consider contralateral ICA occlusion or age alone as particularly feared risk factors. Post-CEA restenosis is another contentious topic. Those who embrace CAS consider this condition a prime target for endovascular treatment. Some vascular surgeons consider post-CEA restenosis a condition best treated surgically; others question the need for intervention.
Predictably, many vascular surgeons tend to view the high-risk group as nothing more than a handful of rare cases. Interventional specialists insist the group may be much larger. As far as restenosis, personal experience has taught me that most surgeons performing CEA (myself included) would prefer not to repeat carotid surgery if there is a reasonable alternative.
The Catheterization Craze
The second issue fueling the development of nonsurgical carotid artery revascularization concerns the relentless drive for all things percutaneous and nonsurgical. This trend is not unlike developments in other vascular territories; the promise of ?surgery without the scalpel? stands tall at this time. As a result, carotid interventional techniques (and technologies) have evolved impressively in a relatively short period of time. Although CAS is an appealing and elegant therapeutic approach, many question whether it is as safe as CEA—and whether it will ever equal, or even approximate, the efficacy of the surgical procedure.
We can probably begin to address the safety issue based on rapidly growing experience with cerebral protection devices. Experienced teams in the US and Europe are duplicating a CEA surgery-related stroke rate of less than 2%. We have already achieved this level of safety in our own practice: Not one ischemic stroke occurred in the last 120 procedures, which were all carried out under embolic protection. On the other hand, very little is currently known about long-term clinical efficacy of CAS. Ongoing trials will eventually provide these data, but it may be several years before they are available.
APPLY CAS CAREFULLY
Enthusiasm notwithstanding, we must give patients full disclosure of the investigational nature of CAS, and we must also inform them about the continuing uncertainties regarding long-term results. We also need to keep in mind that, today, treating all prospective patients with CAS may be inappropriate if performed outside the confines of a well-controlled trial. In this context, CAS should be considered only when dealing with lesions, anatomies, or patients that constitute (more or less) accepted high-risk scenarios for CEA (Figures 2 and 3).
To date, we have performed approximately 350 carotid artery stent procedures working in a state-of-the-art angiography suite, which provides the imaging/interventional capabilities critical to achieving optimal outcomes. I must admit I work in a unique environment—one that includes use and control of an interventional lab in the hands of a surgical team. The majority of my surgical colleagues are not as fortunate.
Beyond controversy and uncertainty, there are many reasons why vascular surgeons are essentially excluded from current developments. Only a minority of surgeons has the necessary catheter and imaging skills and access to training is difficult. Few surgeons are ever invited to participate in CAS imaging trials. Finally, surgeons have limited access to hospitals’ best imaging suites. Overcoming these handicaps will not be easy, but I suggest two promising approaches:
Attitude. An attitude change on the part of surgeons is clearly in order. It is going to be difficult (if not impossible) to access training opportunities and learn an advanced technique while denouncing it at the same time.
Diagnostic angiography. This procedure can and probably should be performed in the majority of patients prior to carotid revascularization. It is an entirely legitimate procedure, and one for which surgeons should have no difficulty finding candidates. Make an effort to gain access to imaging diagnostic suites and perform these diagnostic procedures, which constitute the foundation of interventional approaches in the aortic arch and its branches.
THE FUTURE OF CEA
A surgeon’s transition from cut-and-sew approaches to image-guided therapy represents a giant evolutionary leap that requires training and dedication; this can be regarded as a positive challenge. Unfortunately, a number of my colleagues consider it a backward shift from a proven, effective therapy to what they see as a perhaps ?sexy,? but largely unproven and likely dangerous intervention.
The reality is that progress will continue and interventional techniques and embolic protection devices will be further refined, whether vascular surgeons like it or not. In our own practice we currently treat nearly two-thirds of patients who have severe ICA stenosis with percutaneous intervention (with patients enrolled in one of several ongoing trials); we reserve CEA for a slowly but inexorably shrinking minority. We routinely perform diagnostic angiography with selective aortic branch catheterization and obtain intracranial images, either beforehand or as the first step of the CAS intervention. This trend is likely to be duplicated in other practices in the future.
Many cardiologists plan to become active in CAS practice if they are not currently involved. They find themselves well positioned, with ample access to patients with CAD, control of imaging suites, and a familiarity with catheter-based techniques. Unlike the abdominal aortic aneurysm scenario, CAS-related complications and troubleshooting are of an interventional, not surgical, nature. In other words, the vascular surgeon can be easily bypassed and so must find a way to retain a starring role in the future treatment of carotid artery stenosis. In my opinion, embracing and performing CAS are inescapable components to ensuring that future.
I am sure we will still be performing CEA in 2007, but probably not frequently. To quote vascular surgeon Bruce Brener, MD, in a recent presidential address: “Carotid endarterectomy is a great operation; I will miss it.”
Frank J. Criado, MD, is Director of the Center for Vascular Intervention and Chief of the Division of Vascular Surgery at Union Memorial Hospital–MedStar Health in Baltimore, Maryland. Dr. Criado may be reached at (410) 235-6565; email@example.com.