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Editorial |
1 From the Department of Radiology, Reading Hospital and Medical Center, 6th and Spruce Sts, West Reading, PA 19603 (D.S.); and Department of Interventional Neuroradiology, Miami Cardiac & Vascular Institute, Miami, Fla (J.J.C.). Received September 21, 2004; accepted September 22. Address correspondence to D.S. (e-mail: davidsacks@pol.net).
EDITOR’S NOTE: A similar version of this Editorial may also appear in other imaging and nonimaging journals that are publishing the document on which this Editorial comments.
Carotid endarterectomy is a procedure that has been proved to decrease the long-term risk of stroke but only if performed with excellent results and very few complications in appropriate patients. Carotid artery stent (CAS) placement is a minimally invasive alternative that must fulfill these same criteria to be beneficial. CAS procedural training has been included in relatively few formal training programs in the past, thus necessitating these postgraduate guidelines; future practitioners would ideally acquire these skills in formal fellowships with appropriate supervision. The critical necessity of procedural excellence combined with the potentially dangerous nature of this new procedure was fundamental to the consensus recommendations published in the current issue of Radiology (1) for training to perform the procedure of CAS placement. This consensus document was written by members of the neurology, neurosurgery, neuroradiology, interventional neuroradiology, vascular neurology, and interventional radiology specialties and has been endorsed by their respective professional societies. These recommendations include minimum specified formal training in both cognitive neuroscience and technical and procedural skills and can be summarized as follows:
1. A minimum of 6 months of formal cognitive neuroscience training in an Accreditation Council for Graduate Medical Education (ACGME)-approved program is required in neuroradiology, neurosurgery, neurology, and/or vascular neurology.
2. All neuroscience societies reaffirm the validity of defined ACGME-approved training programs.
3. Cervicocerebral angiography training and resultant credentialing is required, with an accumulated total of 100 diagnostic cervicocerebral angiograms before postgraduate training in CAS procedures.
4. CAS training sufficient to meet previously published standards (pathway 1: 25 non-CAS procedures plus a 16-hour comprehensive continuing medical education CAS "hands-on" course and least four supervised successful and uncomplicated CAS procedures; pathway 2: 10 consecutive supervised CAS procedures) (2).
5. Outcomes of cases during and after training for both diagnostic cervicocerebral angiography and CAS placement must meet the quality thresholds of previously published standards (2).
These recommendations are not without controversy. Criticisms might include (a) the lack of coauthorship with members from the specialties of cardiology and vascular surgery; (b) the possible logistic difficulty of obtaining sufficient experience in diagnostic cervicocerebral angiography at a time when this procedure may be declining in frequency because of noninvasive imaging; (c) the logistic difficulty of obtaining the recommended cognitive neuroscience training; (d) the suggestion that measuring outcomes is more "relevant" than requiring specific training; (e) the possibility that these recommendations are motivated by the desire to protect the CAS procedure "turf" for radiologists, who have historically been the only professionals with ACGME-approved residency training programs that include diagnostic cervicocerebral angiography and who have performed the vast majority of these procedures; (f) the suggestion that the recommendations will reduce access to care for patients who can benefit from CAS placement; and (g) the effect of these recommendations on those who are already performing this procedure but do not meet the recommended standards.
The authoring societies of the report (1) include every clinical specialty with formal cognitive neuroscience training; the recognized complexity of neurologic conditions was used as a basis for recommending an appropriate amount of such training as a prerequisite for performing interventions that affect the brain. It would be ideal to have consensus on training from all of the medical specialties involved in this procedure. However, the above-described controversies have prevented consensus within the American Heart Association for years. One stent and one embolic protection device have been narrowly recommended for approval for CAS placement by a Food and Drug Administration advisory panel; another was recently approved for use, and it is expected that reimbursement by insurers will soon follow. Owing to the intense interest in this innovative but dangerous procedure with varying degrees of benefit for individual patients, our societies believed it was essential to have an expert consensus recommendation for training.
Are these training recommendations reasonable? Training standards have been in existence for decades and are the hallmark of medical education but are usually defined in terms of months rather than procedures. These requirements for defined formal cognitive training, as well as procedural training, in diagnostic arteriography are, however, directly analogous to the requirements to perform coronary interventions. The official American College of Cardiology requirements include 24 months of cognitive training and 300 diagnostic coronary angiograms (with resultant credentials to perform cardiac catheterization) before postgraduate training in coronary interventions (3–7). Six months of neuroscience training prior to neurovascular interventions is considerably more lenient than the training required prior to coronary vascular interventions—24 months—and certainly far less than the minimum total for credentialing in coronary intervention—36 months. Some of the authors in our group strongly believed that 12 months would be more appropriate, but the final consensus was to mandate 6 months, as this is thought to be extremely reasonable.
For radiologists, confirmation of the necessary cognitive training is documented by passing the radiology board certification examination, including the neuroradiology and interventional radiology sections. With regard to technical skills, it is necessary to be fully trained in diagnostic neurovascular procedures prior to performance of interventions, similar to the situation with coronary training.
Peer-reviewed published scientific evidence demonstrates a substantial learning curve for the performance of diagnostic cervicocerebral angiography, with 100–200 cases necessary to become truly proficient (8). Prior recommendations from the American Heart Association for peripheral vascular intervention mandate 100 procedures before peripheral intervention (9); to require less for the least forgiving organ in the body would appear to be foolish. It is for this reason that a requirement of 100 diagnostic cervicocerebral angiograms has been previously mandated in the published literature by the specialties of neurology, neurosurgery, neuroradiology, and interventional neuroradiology prior to training in the specialty of endovascular surgical neuroradiology (10,11) and was again specified in the current document (1).
In previously published statements (3–7,9), both the field of cardiology (for cardiac interventional procedures) and the neuroscience specialties do not lower the number of training cases for those with catheterization experience, but the training requirements are designed to be minimally sufficient for those who have no prior experience. Would a physician with extensive and sophisticated catheterization skills, such as an interventional cardiologist, vascular surgeon, or interventional radiologist with peripheral (nonneurovascular) experience, possibly require a lesser degree of training to achieve a comparable outcome? Would a physician with extensive experience treating cerebrovascular arterial occlusive disease with surgical techniques similarly need a lesser degree of training? Many of these physicians believe that their current skills in other vascular beds substantially overlap with the skills necessary to perform diagnostic and interventional neurovascular procedures. Results of published series indicate that prior endovascular experience is certainly advantageous when learning this new procedure, but peer-reviewed published series of CAS experience by just such highly trained and competent individual physicians suggest that there is still a very long learning curve, even for the "best of the best" (12,13). There is no evidence or consensus at this time to confirm that neurovascular training can be abbreviated for the majority of physicians who have catheterization skills in other vascular territories.
While it is recognized that some practitioners may indeed learn faster than others, every medical society with ACGME-approved training in the neurosciences believes that a specified minimum of training for CAS placement is entirely reasonable. This is particularly true in view of the fact that these requirements represent only a fraction of the case requirements specified by the American College of Cardiology, American Heart Association, Society for Vascular Surgery, and other vascular societies for peripheral endovascular interventions (3,9,14–16). For a procedure in which stroke and death are routine occurrences and with peer-reviewed documented evidence of a considerable learning curve, it is the belief of neurovascular experts that shortcuts in training would not be optimal for the patients who are to be treated in the future.
There is no question that outcomes are critical to a quality-improvement program. However, post hoc review cannot substitute for suitable training by an appropriately qualified supervisor. Poor performance due to inadequate training will indeed show up as poor outcomes; but by then it is too late to prevent harm to patients, which in this case would be stroke and death. Diagnostic cervicocerebral angiography carries a permanent stroke risk of 0%–5.7% (8,17–22) and is higher among those with the least training and experience (18,23). CAS placement carries a stroke risk of 4.4%–12% (24–32) and also has a substantial learning curve (12,13). Adequate training prior to the granting of credentials is the standard and accepted means of protecting patients in all medical disciplines and should be essential in this arena as well.
It is possible for many physicians to acquire the necessary training and experience in 100 diagnostic cervicocerebral arteriograms. The most recent Medicare data show that in 2002, at least 92 000 cervicocerebral arteriograms (Current Procedural Terminology codes 75680 and 75676, respectively, for bilateral or unilateral cervical carotid arteriography) were performed, compared with 109 000 performed 5 years previously (33). This is an ample number of appropriately indicated procedures to train large numbers of physicians. However, these current requirements will be no easier to meet for radiologists in training than for practitioners in other specialties. Current general radiology graduates will almost uniformly be unqualified, and a recent survey of specialty training in interventional radiology fellowships indicates that only 11% of current trainees will have performed this number of diagnostic cervicocerebral arteriograms during their fellowship training (34). Therefore, it is expected that the overwhelming majority of radiologist, neuroradiologist, and interventional radiologist trainees will not meet this standard and will require additional training.
This fact has caused considerable angst among the radiologist authors and the members of our represented societies, as well as among those from the fields of neurology and neurosurgery. This recommendation for high-quality training was based on what we thought was best for patient care. The possible difficulty in meeting this recommendation does not mean that the standard should be lowered if such training is necessary to achieve good clinical outcomes. Protecting the turf of CAS placement for radiology was not our motivation, and the current recommendations for training will actually vastly decrease the numbers of radiologists who could offer this service. The motivation for these recommendations for training was based on peer-reviewed evidence and the belief that these procedures involving an unforgiving organ—the brain—should be performed only by physicians with adequate preparation, training, and skill.
Will patients be denied care that they need if physicians must fulfill rigorous training requirements to perform CAS placement? Industry estimates of numbers of CAS procedures range from 20 000 to 100 000 per year within this decade. If an interventionist were to perform only one procedure per day, or 250 per year, this would necessitate only 300 doctors in the United States to provide care for the entire population of patients now undergoing endarterectomy. An increase in the number of physicians to 500, with 10 cases performed each week, would allow these physicians to perform 250 000 procedures. An increase of 100 practitioners every year would easily allow for an additional 50 000 cases per year. Even if there are far fewer diagnostic cerebral arteriograms obtained in future years (compared with the 92 000 in Medicare patients alone in 2002), there should still be ample numbers to train the number of physicians needed to provide CAS services in this country.
The recommendations will reduce geographic access to care for patients to be treated with CAS; every small hospital in the nation may not be performing this procedure. CAS placement is an elective procedure. Transfer to an appropriate expert or facility is therefore entirely reasonable and has been the standard of care for cardiac disease for decades. As with carotid endarterectomy, a satisfactory benefit-risk ratio for CAS placement is critically dependent on the ability to achieve extremely low rates of stroke, myocardial infarction, and death in the perioperative period and a high rate of stroke reduction compared with the rate associated with the long-term natural history of the disease (35). The intent of these standards is that CAS placement will be properly limited to performance by expert physicians with adequate training and experience to perform this procedure for appropriate indications and with excellent outcomes, so that this procedure will actually have the desired result of decreasing the total number of strokes.
There are physicians who are already credentialed to perform CAS procedures in their institutions who may not meet our recommendations. No procedure springs fully developed into clinical practice like Athena from the head of Zeus. Innovative and pioneering physicians have created and developed the procedure of CAS placement and, in the process, have worked through their own personal learning curve, some with great difficulty and sacrifice. Training and credentialing standards follow this innovative work, similar to the process for new interventional radiology procedures such as transjugular intrahepatic portosystemic shunt creation, uterine artery embolization for treatment of fibroids, and vertebroplasty. It would be an inappropriate abuse of the training standards we offer to use those standards to deny the validity of credentials and competency for CAS placement already earned by physicians who have documented acceptable outcomes.
What does the future hold? In the short term, there will be other training standards that suggest other training criteria for CAS procedures issued by other specialty societies who were not authors of the current document (15). Hospital credentialing committees will be faced with conflicting standards and will have to make decisions as to which standards they will follow. The authors of the current document (1) have done their best to base standards on scientifically supported evidence, with concern for patient safety paramount. The most valid scientific support will come from studies that need to be performed to evaluate patient outcomes versus training for interventionists experienced in other vascular areas.
Simulators will play a role in training—although at this time it is an unknown role—and at present there is no proved scientific validation for accepting work on a computer as a substitute for approved supervised training with a real patient. An educated guess was used in our document to say that simulators might replace as much as 20% of the live training cases, but in truth the role of simulators is not yet known. Many physician societies are in the process of evaluating their appropriate role in initial training, as well as in recertification.
More studies are needed to demonstrate the clinical value of CAS placement compared with that of carotid endarterectomy or best medical therapy, and such studies are ongoing. The Food and Drug Administration panel was sharply divided as to whether CAS placement is appropriate for asymptomatic patients at high surgical risk (36). It is unknown if stent placement is appropriate for any patients at average surgical risk: Large, lengthy, and well-controlled randomized trials have produced results that have been marginal for the benefit of endarterectomy in asymptomatic patients, even when performed by excellent surgeons. It is unknown if the results of CAS procedures in published trials can be generalized to routine clinical practice, but currently published results do not support the generalized application to large numbers of asymptomatic patients. The costs of not knowing these answers could be stroke and death for some patients. Within the radiology community, there will need to be a shift to more experienced practitioners for performance of diagnostic cervicocerebral arteriography to achieve the recommended high degrees of proficiency. In order to meet the training numbers for CAS procedures, diagnostic cervicocerebral arteriography may need to be performed by physicians who do or will perform carotid interventions and cease to be performed by others. Finally, the NeuroVascular Coalition, which created these CAS training standards, has opportunities to work together as a multispecialty group to advance stroke education and care for the benefit of our patients.
FOOTNOTES
Authors stated no financial relationship to disclose.
See also the article by Connors et al in this issue.
REFERENCES
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  D. Pelz, T. Andersson, M. Soderman, P. Lylyk, and M. Negoro Advances in Interventional Neuroradiology 2005 Stroke, February 1, 2006; 37(2): 309 - 311. [Full Text] [PDF]
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 A. V. Proto Radiology 2005--What's Happening? Radiology, January 1, 2005; 234(1): 5 - 7. [Full Text] [PDF]
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