Standards of Practice in Acute Ischemic Stroke Intervention: International Recommendations

1. Facilities

Facilities that must be available on site include:

• Stroke unit beds: a sufficient number of stroke unit beds should be available in stroke units to accommodate interventionally treated stroke patients at any time.

• Intensive care unit.

• A radiology/neuroradiology service, with competence in neuroimaging, and a suitable angiography room (as defined below): high quality, rapidly available noninvasive imaging is vital to the management of the acute stroke patient. At a minimum, CT scanners should be available on a 24/7 basis to image patients with noncontrast CT and CT angiography. The availability of CT perfusion and/or MRI may also assist in patient selection for AISI beyond 6 hours from onset. The necessary technologists and support personnel for this imaging should be available and onsite at the time of patient admission. Diagnostic radiologists/neuroradiologists with sufficient training and experience in the interpretation of these imaging studies shall be available on a 24/7 basis. Finally, cerebrovascular ultrasound facilities will be available.

• A team of trained acute stroke neurointerventionists.

• A dedicated ‘stroke unit’ and a ‘stroke team’ with fully trained stroke physicians.

• A department of neurosurgery ideally in house or, if that is not possible, in a nearby hospital.

2. Angiography Suite

A suitable interventional angiographic suite implies the ability to routinely accommodate general anesthesia. Optimally, procedures should be carried out under the image guidance of a biplane digital angiography unit with flat panel CT capabilities and necessary software and hardware to perform high quality cerebral angiography.

As a minimum, each suite should include a single plane high resolution digital subtraction angiography unit with road mapping capabilities.

Radiation protection measures in accordance with national regulations should be in place with designated individuals responsible for carrying out the necessary checks and audits.

3. Treatment Availability

AISI should be offered to every appropriate patient according to international guidelines, not excluding/discriminating against any patient, appropriate at the right time to obtain the best results, with population treatment access equity, in centers providing safe, effective, and efficient treatment.

A suitable level 2 center should be able to provide the services defined in the definition section, on a full time basis, 24/7, all year around.

4. Procedural Volume

The randomized trials demonstrating a clear benefit from thrombectomy were almost exclusively performed in high volume centers. It has been shown that high volume centers have a significantly lower mortality, even if the patient has to be transferred from a low volume center. Rinaldo et al found that centers performing 35 or more thrombectomy cases per year would classify as ‘high volume’ and offer the lowest mortality rate for patients.¹⁵ Similarly, the American College of Cardiology Foundation, the American Heart Association, and the Society for Cardiovascular Angiography and Interventions suggest a minimum of 36 percutaneous coronary interventions for acute myocardial infarction per year per center as a minimum requirement.¹⁷

We acknowledge that the thresholds listed below are generally low. Multiple regional/national recommendations with higher limits are available and should be observed in regions/countries having already advanced healthcare networks providing services for AIS patients. The current recommendations are international and have to be compatible with the development of this new activity in areas and countries where there had been previously limited availability. Subsequently, these thresholds should be considered as the minimum caseload providing the lowest limit of safe operation. With the increased implementation of AISI in the world, it may be desirable to revise these thresholds in the future.

On the other hand, we also acknowledge that these thresholds are potentially difficult to reach in newly created level 2 centers and recognize that, during a transitory period, the activity can be below the threshold numbers, as long as it is expected that the volumes would be reached within 12–24 months.

With all of the above in mind, the suggested thresholds for annual procedure volume to maintain the competence for AIS endovascular treatment are the following:

• Each level 2 center shall perform a minimum number of intracranial thrombectomy procedures for ELVO per year. The global consensus group recommends a minimum of 50 procedures per center per year.

• Including the aforementioned thrombectomy procedures, each level 2 center shall perform a minimum total number of neuroendovascular procedures (diagnostic and interventional) per year according to national requirements. The global consensus group recommends a minimum of 120 per center per year.

• Each neurointerventionist working in a level 2 center must perform a minimum number of acute intracranial thrombectomy procedures per year, in accordance with national requirements. The global consensus group recommends a minimum of 15 procedures per neurointerventionist per year.

• In addition to the aforementioned thrombectomy procedures, each neurointerventionist in a level 2 center should perform a minimum number of total neuroendovascular procedures per year according to national requirements. The global consensus group recommends a minimum of 50 procedures per neurointerventionist per year.

5. Operational Guidelines/Medical Personnel

5.1 Stroke Team

Outstanding stroke care does not exist in a vacuum solely focused on the procedure but instead is part of a successful multidisciplinary team. The stroke team comprises fully trained stroke physicians (vascular neurologists or neurointensivists), allied professionals, and nurse that are all led by a stroke physician with a strong background in the management of neurovascular disease.

5.2 Level 2 Stroke Intervention Team

• The team should have a minimum of three clinicians with training and qualification in AISI.¹⁸

• The team should organize 24/7/365 acute ELVO stroke coverage (possibly in a rotation system organized with other level 2 centers or a level 1 center).

• It is recommended that stroke neurointerventionists involved in AISI maintain outpatient clinics for follow-up and have admitting privileges either in units/beds dedicated to Interventional neuroradiology or in other appropriate inpatient facilities.

• The stroke neurointerventionist/interventionist, in collaboration with the stroke team, should have shared responsibility for preoperative and postoperative patient care with input from the appropriate specialties.

• AISI should ideally be practiced in neurointerventional teams with the possibility to exchange experience and knowledge. Clinical research should be encouraged. The solitary practice of AISI is strongly discouraged.

5.3 Anesthesia Team

There shall be 24/7 in hospital anesthesia coverage with anesthetists with experience in caring for patients undergoing AISI. At many centers, the use of anesthesia, whether monitored anesthetic care or general anesthesia, is routine during thrombectomy. Even at centers primarily using moderate sedation, patients may deteriorate clinically prior to, or during, the procedure such that immediate access to general anesthesia is necessary to safely complete the procedure.

5.4 Others

Given the significant amount of assistance stroke patients need re-integrating into the community, the center should have access to physical therapy, speech therapy, occupational therapy services, as well as a coordinated plan for assessment for rehabilitation needs.

5.5 Individual Procedures

With regard to individual procedures, ideally the following staff roles are present for each case:

• One first operator: a neurointerventionist

• One assistant: a second scrubbed individual (ie, a supporting AIS interventionist, physician in training (resident or fellow), nurse practitioner, physician assistant, a scrub nurse, or a radiographer)

• One radiographer

• One nurse or nurse assistant

• Regardless of the type of anesthesia, an anesthesiology service must be readily available 24/7.

As a minimum, a neurointerventionist, a radiographer, and appropriately trained nursing must be present.

5.6 Quality Improvement Processes

Treatment of AIS by using AISI techniques is a novel method that involves the consumption of significant human and material resources and carries the risk of severe complications. Accurate documentation of medical and technical details as well as patient outcome and follow-up results is inevitable to ensure the highest benefit of such complex and demanding procedures.

To secure such documentation and data management, it is recommended that:

• The level 2 stroke center team includes a dedicated individual, preferably a stroke nurse or a stroke fellow, with the responsibility of data recording and data base management.

• All technical and clinical data of AISI procedures, patient outcomes, and follow-up must be entered into an electronic data base either locally or (preferably) nationally or internationally.

• The center shall establish target time metrics for all cases in accordance with the most recent requirements by international standards. Cases that exceed their chosen metrics should trigger an internal process for quality improvement.¹⁷

• The database should be regularly audited. At a minimum, process metrics such as time from arrival to intravenous tissue plasminogen activator, to start of angiography, and to recanalization, as well as overall recanalization rates, are to be reviewed and compared against reasonable published benchmarks.

• The center provides routine continuing education (suggested minimum of 8 hours per year) related to cerebrovascular disease and stroke for all core members of the center, as designated by the medical director.

• All cases of symptomatic intracranial hemorrhage shall be reviewed. For the purposes of this document, we broadly define symptomatic intracranial hemorrhage as the presence of new intracranial hemorrhage on post-treatment brain imaging, with clinical deterioration that is potentially attributable to the hemorrhage.

• Standardized care pathways should be implemented with clinical practice guidelines, order sets, and other tools to ensure consistent care delivery and minimize practice variability. This should apply to providers, and nursing and ancillary staff. These pathways should be developed by the multidisciplinary Asian-Australian Federation of Interventional and Therapeutic Neuroradiology (AAFITN), Australianand New Zealand Society of Neuroradiology (ANZSNR), American Society of Neuroradiology (ASNR), Canadian Society of Neuroradiology (CSNR), European Society of Minimally Invasive Neurologic Therapy (ESMINT), European Society of Neuroradiology (ESNR), European Stroke Organization (ESO), Japanese Society for NeuroEndovascular Therapy (JSNET), The French Society of Neuroradiology (SFNR) Ibero-Latin American Society of Diagnostic and Therapeutic Neuroradiology (SILAN), Society of NeuroInterventional Surgery (SNIS), Society of Vascular and Interventional Neurology (SVIN), World Stroke Organization (WSO), World Federation of Interventional Neuroradiology (WFITN) leadership of the center and reflect evidence based practice.

6. Community and EMS Outreach

Outstanding stroke care starts not in the hospital but in the field. Increasingly, operators will likely promote selection of the most appropriate destination for suspected ELVO patients based on distance to a center from the field.¹⁹ Such a mechanism should decrease time to treatment. As such, the level 2 center should interface with local emergency medical services (EMS) in order to coordinate care in the prehospital arena.

Specifically, we feel there are some key items in this area.

• Representatives of the center shall work with local and regional EMS officials to ensure they are aware of the system's capabilities, as well as which patients (based on the region's chosen severity scale) are appropriate for direct field triage to the level 2 or 1 centers.

• Additionally, some patients may be distant from the level two (or 1) and present to a level 3 center. The level 2 center should work with these local centers to assist in identification of suspected or confirmed ELVO patients and facilitate rapid transfer as part of a ‘hub and spoke’ model of care. However, if a level 1 center is available in a similar transfer time, it is preferable that interfacility transfers are directed to the highest level facility.

• A mechanism should exist for providing feedback to the EMS and referring non-thrombectomy centers to highlight which aspects of care went well and identify areas for improvement. This would be similar to quality assessment work done on patients presenting directly to the level 2 and 1 centers.