<em>EJMINT</em> Editorial, 2016: <strong>1607000288</strong> (18th February 2016)

Background

Ischemic stroke is a leading cause of death and disability worldwide. Much of the long term disability occurs in patients with Emergent Large Vessel Occlusion (ELVO), where an acute occlusion of a major intracerebral artery results in significant clinical deficit [1]. Until recently, intravenous tissue plasminogen activator (t-PA) was the only proven treatment for ELVO.

However, the landscape of stroke treatment has changed with the publication of multiple, randomized multicenter prospective trials that provide Class 1, Level A evidence in support of endovascular embolectomy. For patients with acute occlusion of the internal carotid artery (ICA) or M1 segment of the middle cerebral artery (MCA) and a corresponding clinical deficit, the use of mechanical thrombectomy on average results in improved clinical outcomes compared with best medical therapy alone [2-6]. These results have led to guideline recommendations advocating for endovascular treatment in addition to t-PA for patients with ELVO, and offered as first line therapy for patients that are not eligible for intravenous thrombolysis [7-9]. However, achieving the best possible clinical outcomes with endovascular stroke treatment requires physician expertise, and mandates structured training and education of physicians providing endovascular stroke treatment. A recent meta-analysis reviewed the 5 positive stroke thrombectomy studies published in 2015; the vast majority of thrombectomies were performed by experienced neurointerventionalists, including interventional neuroradiologists, endovascular neurosurgeons, and interventional neurologists working routinely on neuroradiological interventional procedures [10]. None of the studies allowed those without previous experience in the use of these devices in the treatment of acute ischemic stroke to enroll patients. The centers participating in these trials offered endovascular stroke therapy 24 hours a day (with the exception of those in the EXTEND-IA trial) with expertise in vascular neurology and neurocritical care in a comprehensive stroke center. On-site expertise in vascular neurology and neurocritical care is paramount to achieving good clinical outcomes.

Geographical limitations to rapid delivery of mechanical thrombectomy have led some to suggest physicians without prior experience or formal training should consider providing coverage for these procedures. A multidisciplinary British Intercollegiate Stroke Working Party put forth a document outlining the safe delivery of mechanical thrombectomy, which highlights that operators should not normally carry out procedures with which they are unfamiliar and that they should recognize ad-hoc arrangements are not in the best interest of patients [11].

It is also important to recognize that modern endovascular stroke therapy focuses on direct clot removal with mechanical devices, as compared with previous paradigms where intra-arterial thrombolytic infusion was an acceptable treatment option for large vessel occlusions [12]. The technical skills needed to safely deliver devices into the intracranial circulation are significantly more involved than simply placing a catheter for medication infusion. Catheter skills from other circulations do not replace the need for formal training in safe intracranial microcatheter navigation and device placement.

Acute ischemic stroke is a complex disease and successful endovascular treatment is based on the comprehensive ability to rapidly integrate multiple pieces of information, including: the patient’s history, clinical examination, neuroradiological studies, and subsequently formulate a treatment plan. Both patient selection and procedural expertise are critical to achieve a good clinical outcome. Hence, there is a clear rationale for formal training in both clinical neuroscience and interventional neuroradiology.

The purpose of this document is to define what constitutes adequate training for physicians who provide endovascular treatment for acute ischemic stroke. These training guidelines are modeled after prior standards of training documents such as the training, competency and credentialing standards for diagnostic cerebral angiography, carotid stenting and cerebrovascular intervention [13] and the performance and training standards for endovascular ischemic stroke treatment [14], written and endorsed by multispecialty groups. In addition, the importance of organ specific training, rigorous quality improvement benchmarks, and minimum volume requirements needed to maintain high quality care has been extensively described for acute myocardial infarction, an analogous time sensitive disease [15].

This document represents the cumulative work of the societies listed below, and represents an international consensus on adequate training to safely and effectively perform these procedures:

Society of NeuroInterventional Surgery (SNIS)
American Academy of Neurological Surgeons/ Congress of Neurological Surgeons (AANS/CNS)
American Society of Neuroradiology (ASNR)
Asian Australasian Federation of Interventional and Therapeutic Neuroradiology (AAFITN)
Australian and New Zealand Society of Neuroradiology - Conjoint Committee for Recognition of Training in Interventional Neuroradiology (CCINR) representing the RANZCR (ANZSNR), ANZAN and NSA
Canadian Interventional Neuro Group (CING)
Swiss Society of Neuroradiology (ESNR)
Swiss Society of Minimally Invasive Neurologic Therapy (ESMINT)
Japanese Society for Neuroendovascular Therapy (JSNET)
Sociedad Ibero Latino Americana de Neuroradiologica (SILAN)
Society of Vascular and Interventional Neurology (SVIN)
World Federation of Interventional and Therapeutic Neuroradiology (WFITN)

Physician Qualifications

Physicians providing intra-arterial treatment for acute stroke are required to have appropriate training and experience for the performance of neuroangiography and interventional neuroradiology.

We recognize that the specific training pathways may differ across nations, but the consensus is to mandate adequate training to perform emergent endovascular stroke intervention. These cognitive requirements consist of baseline training and qualifications as well as ongoing professional education, which are essential for safe and efficient patient management.

It is also important to point out that these qualifications are for new practitioners who are not currently performing acute stroke intervention with mechanical thrombectomy. We understand that there are current practitioners (who are board certified or board eligible in radiology, neurology or neurosurgery) who may have trained prior to the establishment of formal training pathways, and have acquired the necessary skills listed below to safely and effectively treat these complex patients. We would still expect the same requirements for maintenance of qualifications as listed below.

I. Baseline training and qualifications:

Residency training (in radiology, neurology or neurosurgery) which should include documented training in the diagnosis and management of acute stroke, the interpretation of cerebral arteriography and neuroimaging under the supervision of a board-certified neuroradiologist, neurologist or neurosurgeon with subsequent board eligibility or certification. The residency program and supervising physicians should be accredited according to national standards as they pertain to the countries involved. Those physicians who did not have adequate such training during their residencies must spend an additional period (at least one year) by training in clinical neurosciences and neuroimaging, focusing on the diagnosis and management of acute stroke, the interpretation of cerebral arteriography and neuroimaging prior to their fellowship in neuroendovascular interventions.

AND
Dedicated training in Interventional Neuroradiology under the direction of a Neurointerventionalist (from neuroradiology, neurology or neurosurgical training background), at a high-volume center. It is preferred that this is a dedicated time (minimum of one year), which occurs after graduating from residency (i.e., a fellowship). A training program accredited by a national accrediting body is also strongly preferred but not required. Published standards exist for various countries [16-22]. Within these programs, specific training for intra-arterial therapy for acute ischemic stroke should be performed, including obtaining appropriate access even in challenging anatomy, microcatheter navigation in the cerebral circulation, knowledge and training of the use of stroke specific devices and complication avoidance and management.

While various national standards will have differing procedure requirements, we encourage practitioners to be meet their national minimum procedural and training standards. Fellowships which are not accredited by national credentialing bodies should still have adequate training to meet their local minimum procedure requirements. In addition, we expect that minimum training numbers for stroke thrombectomy may increase in future revisions of these standards given the recent developments in the field.

II. Maintenance of physician qualifications:

It is vital that the physician have ongoing stroke specific continuing medical education. A minimum of 16 hours of stroke specific education every 2 years is suggested. Individual physician outcomes should conform to national standards and institutional requirements. In addition, the physician should participate in an ongoing quality assurance and improvement program. The goals of this quality assurance program for stroke therapy would be to monitor outcomes both in the peri-procedural period and at 90 days. The quality assurance program must review all emergency interventional stroke therapy patients. In addition, participation in a national quality improvement registry, when available, is also encouraged. Outcomes should be tracked and recorded. While threshold levels for recanalization, complication rates, etc. have yet to be established, we suggest the following as a minimum:

Successful recanalization (modified TICI 2b or 3) in at least 60% of cases.
Embolization to new territory of less than 15%.
Symptomatic intracranial hemorrhage (i.e. Parenchymal Hematoma on imaging with clinical deterioration) rate less than 10%.

Hospital requirements:

Successful treatment of the ELVO patient does not occur in a vacuum, but rather with the framework of a multi-disciplinary team. As such, we feel it is critical that the patients be treated in a center, which has 24/7 access to the following:

Angiography suites suitably equipped to handle these patients, as well as equipment and capability to handle the complications.
Dedicated stroke and intensive care units (preferably dedicated neuro-intensive care unit), staffed by physicians with specific training in those fields.
Vascular neurology and Neurocritical care expertise.
Neurosurgery expertise, including vascular neurosurgery
All relevant neuroimaging modalities (CT/CTA, MR/MRA, Trans-cranial Doppler [TCD]), including 24/7 access to CT and MRI.

Summary

We, as a group of international multi-disciplinary NeuroInterventional societies involved in the endovascular treatment of acute ischemic stroke, have put forth these training guidelines. We believe that a neuroscience background, dedicated neurointerventional training, and stringent peer review and quality assurance processes are critical to ensuring the best possible patient outcomes. Well-trained neurointerventionalists are a critical component of an organized and efficient team needed to deliver clinically effective mechanical thrombectomy for acute ischemic stroke patients.

References

Lima FO, Furie KL, Silva GS, et al.; Prognosis of untreated strokes due to anterior circulation proximal intracranial arterial occlusions detected by use of computed tomography angiography; JAMA Neurology 2014; 71(2): 151-7. [PubMed] [Full Text Sources]
Berkhemer OA, Fransen PS, Beumer D, et al.; A randomized trial of intraarterial treatment for acute ischemic stroke; N Engl J Med 2015; 372(1): 11-20. [PubMed] [Full Text Sources]
Goyal M, Demchuk AM, Menon BK, et al.; Randomized Assessment of Rapid Endovascular Treatment of Ischemic Stroke; New England Journal of Medicine 2015; 150211090353006. [PubMed] [Full Text Sources]
Jovin TG, Chamorro A, Cobo E, et al.; Thrombectomy within 8 hours after symptom onset in ischemic stroke; N Engl J Med 2015; 372(24): 2296-306. [PubMed] [Full Text Sources]
Saver JL, Goyal M, Bonafe A, et al.; Stent-retriever thrombectomy after intravenous t-PA vs. t-PA alone in stroke; N Engl J Med 2015; 372(24): 2285-95. [PubMed] [Full Text Sources]
Campbell BC, Mitchell PJ, Kleinig TJ, et al.; Endovascular therapy for ischemic stroke with perfusion-imaging selection; N Engl J Med 2015; 372(11): 1009-18. [PubMed] [Full Text Sources]
Jayaraman MV, Hussain MS, Abruzzo T, et al.; Embolectomy for stroke with emergent large vessel occlusion (ELVO): report of the Standards and Guidelines Committee of the Society of NeuroInterventional Surgery; J Neurointerv Surg 2015; 7(5): 316-21. [PubMed] [Full Text Sources]
Powers WJ, Derdeyn CP, Biller J, et al.; 2015 American Heart Association/American Stroke Association Focused Update of the 2013 Guidelines for the Early Management of Patients With Acute Ischemic Stroke Regarding Endovascular Treatment: A Guideline for Healthcare Professionals From the American Heart Association/American Stroke Association; Stroke 2015; 46(10): 3020-35. [PubMed] [Full Text Sources]
Wahlgren, N., Moreira, T., Michel, P. et al.; Mechanical thrombectomy in acute ischemic stroke: Consensus statement by ESO-Karolinska Stroke Update 2014/2015, supported by ESO, ESMINT, ESNR and EAN; Int J Stroke 2016; 11: 134-47
Badhiwala JH, Nassiri F, Alhazzani W, et al.; Endovascular Thrombectomy for Acute Ischemic Stroke: A Meta-analysis; JAMA 2015; 314(17): 1832-43. [PubMed] [Full Text Sources]
White PM; Standards for providing safe acute ischaemic stroke thrombectomy services.
Broderick JP, Palesch YY, Demchuk AM, et al.; Endovascular therapy after intravenous t-PA versus t-PA alone for stroke; N Engl J Med 2013; 368(10): 893-903. [PubMed] [Full Text Sources]
Connors JJ, 3rd, Sacks D, Furlan AJ, et al.; Training, competency, and credentialing standards for diagnostic cervicocerebral angiography, carotid stenting, and cerebrovascular intervention: a joint statement from the American Academy of Neurology, the American Association of Neurological Surgeons, the American Society of Interventional and Therapeutic Neuroradiology, the American Society of Neuroradiology, the Congress of Neurological Surgeons, the AANS/CNS Cerebrovascular Section, and the Society of Interventional Radiology; Neurology 2005; 64(2): 190-8.
Meyers PM, Schumacher HC, Alexander MJ, et al.; Performance and training standards for endovascular ischemic stroke treatment; J Neurointerv Surg 2009; 1(1): 10-2. [PubMed] [Full Text Sources]
Harold JG, Bass TA, Bashore TM, et al.; ACCF/AHA/SCAI 2013 Update of the Clinical Competence Statement on Coronary Artery Interventional Procedures: a Report of the American College of Cardiology Foundation/American Heart Association/American College of Physicians Task Force on Clinical Competence and Training (Writing Committee to Revise the 2007 Clinical Competence Statement on Cardiac Interventional Procedures); Catheterization and cardiovascular interventions : official journal of the Society for Cardiac Angiography & Interventions 2013; 82(2): E69-111.
CAST program requirements; http://www.societyns.org/pdfs/CAST_NES_ProgramRequirements.pdf (accessed 12/15/2015)
ACGME NES program requirements; http://www.acgme.org/acgmeweb/Portals/0/PFAssets/2013-PR-FAQ-PIF/163-182-422_endovascular_neuroradiology_07012013_1-YR.pdf (accessed 12/15/2015)
Picard L, Bracard S, Rodesch G; WFITN recommendations for certification and maintenance of competence in interventional neuroradiology. (Therapeutic neurointervention/endovascular neurosurgery); Interventional neuroradiology : journal of peritherapeutic neuroradiology, surgical procedures and related neurosciences 2014; 20(3): 249-50.
Rodesch G, Picard L, Berenstein A, et al.; Editorial: Interventional Neuroradiology: a Neuroscience sub-specialty? Interventional neuroradiology : journal of peritherapeutic neuroradiology, surgical procedures and related neurosciences 2013; 19(4): 521-3.
CCINR Training standards. http://www.ccinr.org.au/guidelines/ (accessed 12/15/2015)
Hyogo T, Taki W, Negoro M, et al.; Japanese society of neuro-endovascular treatment specialist qualification system. Six years' experience and introduction of an animal model examination; Interventional neuroradiology : journal of peritherapeutic neuroradiology, surgical procedures and related neurosciences 2008; 14(3): 235-40.
Flodmark O, Grisold W, Richling B, et al.; Training of future interventional neuroradiologists: the Swiss approach; Stroke 2012; 43: 2810-3 [PubMed] [Full Text Sources]

This document is being simultaneously co-published by Interventional Neuroradiology, American Journal of Neuroradiology, Journal of Interventional Neurology, Swiss association of Minimally Invasive Neurological Therapy, Journal of Neuroendovascular Therapy, Journal of NeuroInterventional Surgery, Neuroradiology and Neurosurgery.

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Training Guidelines for Endovascular Ischemic Stroke Intervention: An International Multi-Society Consensus Document

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