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The stroke interventionalist
  1. Ansaar T Rai
  1. Correspondence to Dr Ansaar T Rai, Department of Interventional Neuroradiology, West Virginia University Hospital, One Medical Center Drive, Morgantown, WV 26508, USA; ansaar.rai{at}gmail.com

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Endorsement of endovascular stroke therapy by multiple randomized controlled trials now makes it the evidence-based standard of care for acute large vessel occlusions.1 An expected outcome of this endorsement is the debate on who can or should treat acute ischemic stroke. Most of this activity is predicated on the assumption that there is going to be too much stroke to treat and not enough people to treat it, more on that later. Let us examine the ‘who’ and the ‘should’ part first. The multi-society consensus guidelines simultaneously published in several journals2 pretty much restrict stroke interventions to trained and practicing neurointerventionalists. This is bound to irk a few folks. Interventional cardiologists have successfully ventured beyond the heart, partly owing to a pioneering spirit of advancing the limits of minimally invasive therapies and partly because of a financial incentive.

There was an immediate reaction to the published stroke evidence in both the lay cardiology press and in respected journals. However, some of the articles touting the readiness of interventional cardiologists to offer endovascular stroke therapy bring to mind the Dunning–Kruger effect.3 ,4 Described by David Dunning and Justin Kruger in 1999, it is a cognitive bias that leads people to overestimate their abilities. This lack of insight and illusory superiority can affect judgment.5 ,6 Furthermore, skills in one area may induce a sense of invulnerability in another, and the effect may persist despite appropriate feedback.7

Obviously, interventional cardiologists are skilled physicians and that is not where this effect is applied. The Dunning–Kruger effect comes into play because of an assumption that a knack of manipulating wires in the coronary arteries is enough to do that in any blood vessel in the body. The era of drive-by renal angiography8 and an explosion in peripheral vascular interventions9 was driven by this limitless competency. Technological innovations have made minimally invasive procedures safer and simpler in all parts of the body. Thus it is not just the skills that underpin interventional cardiology's success, but the unfettered access to vascular disease that drives the large volumes of non-cardiac vascular interventions. The same risk factors that close off the left main also bring about claudication in the legs and amaurosis fugax in the eye. Why then is it unreasonable for a patient visiting his/her heart doctor to be checked for signs and symptoms of vascular disease affecting other organ systems? It is perhaps preferable to do just that. In our topsy-turvy healthcare system it may be the first or only time for that patient to come across a physician and hence all appropriate care that can be rendered is justified. Here the cognitive skills are as valuable as the technical ones.

Intracranial interventions are different because the vascular histology is different. Suspended in fluid, these friable arteries are less resistant to trauma than extracranial ones. An intracranial dissecting aneurysm rips through the vascular defenses, whereas an extracranial aneurysm is contained in the walls. That is why in the blink of any eye one can be on the wrong side of an artery. An arterial pumper in the confines of the bony skull will exert forces on the brain that within minutes, if not seconds, will render all perfusion inadequate, completely shutting down electrical activity and if not controlled immediately, all life. There is limited, if any, backup for a neurovascular complication; by the time one does a craniotomy one might as well be doing an autopsy. As hard as it is when all anatomy is laid out under elective controlled conditions, it is harder when probing blindly through an occluded middle cerebral artery with the patient gyrating from side to side. Hence a weekend course on cerebral angiography just might not be enough to ensure competency.

The rationale for this demand in increasing the workforce is the expected explosion in cases of acute large vessel occlusions piling up at our emergency rooms. Suddenly, there is going to be so much ischemic stroke that hospitals will be paralyzed (pun intended), physicians overwhelmed, and patients left unattended. The realities, however, are quite the opposite.10 It is not 800 000 or 700 000 strokes that cause of all the morbidity and mortality. Estimates of large vessel strokes amenable to endovascular therapy vary between 50 000 and 100 000. A center performing 10–12 acute stroke interventions per 100 000 of their catchment population will be capturing most of their large vessel strokes.10 Even accounting for the growth in the ageing US population we may reach 50 000 interventions in about 10–15 years. Therapies that protect the ischemic brain and timely transfer of patients with stroke may increase this number but it is nowhere near the mythical volumes of stroke interventions that form the basis for an emergent increase in the workforce. The current supply (of neurointerventionalists) and demand (for large vessel occlusion acute ischemic stroke treatment) plots on the supply–demand curve well below the equilibrium point where these lines cross, indicating an abundant oversupply of the workforce which is projected to remain that way for the foreseeable future.

Almost the entire US population is within an hour of a trained stroke interventionalist and there is not a single stroke center in the country that does not have a neurointerventionalist offering endovascular therapy. Is it really then in a patient's best interest to be treated in a 200-bed community hospital by a physician doing 12–15 procedures a year or a little over one a month, even one who does carotid stenting? That may be naïve at best and dangerous at worst because that approach ignores the intensive medical management required by these patients. Perhaps the best way to utilize our cardiology colleagues’ skills could be in complementing existing neurointerventionalists in established stroke centers. This would provide oversight and develop partnerships.

The neurointerventional community reached significant milestones a year ago when the results of multiple clinical trials affirmed superiority of endovascular therapy over thrombolysis for large vessel strokes. It is now incumbent upon the same community and its leadership that the next steps in disseminating this treatment are carefully planned. Education of patients and community physicians, hospitals and emergency medical personnel, and our representatives in the legislature is the first step. Defining systems of care that efficiently direct patients to the appropriate medical center is another. Reducing door-to-needle times and establishing comparable quality parameters of acute care and outcomes need to be simultaneously developed. This is where we can learn the most from cardiology and the evolution of acute myocardial infarction care. This is where we can tie stroke care to cardiac care and piggyback on the same networks that transfer patients from a center that does thrombolysis to one that does percutaneous coronary interventions. The trauma system is another example of coordinated dissemination of care based on varying capacities of health centers within a region. Hospitals need to see the value of getting patients to the right location within a health system as opposed to putting money into developing these costly therapies at every location.

Another key partner in advancing stroke care is the industry. It is not in anyone's interest, least of all a patient with stroke, when these devices are in the hands of insufficiently trained personnel. It is also not in the industry's interest when complications with a device are highlighted because the operator was not completely familiar or experienced with its use. Everyone will be liable in that case. These issues underscore the need for the neurointerventional community to coalesce around the recent training standards making sure that we neither jeopardize access to care nor the quality of care. Physicians from other specialties such as cardiology or vascular radiology may be incorporated (if needed) but should be subject to similar rigorous criteria.

In summary, at last we have promising treatments for acute ischemic stroke and are entering the next phase of technological innovations for making these approaches safer and more efficacious. As neurovascular physicians it is now our responsibility to develop and promote systems of care that allow more patients access to these therapies in a setting that maximizes their outcomes.

References

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Footnotes

  • Competing interests None declared.

  • Provenance and peer review Commissioned; internally peer reviewed.

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