• stroke

Acute ischemic stroke (AIS) is an emergency that requires rapid treatment by skilled practitioners in order to avoid severe disability or death. It is estimated that AIS accounts for up to 87% of all stroke-related cases worldwide. In the USA the incidence of AIS is approximately 750 000 patients annually, and this rate is expected to increase 25% in the next 20 years.1

The last decade has witnessed remarkable progress in the treatment of this condition. In 2015, five multicenter prospective randomized clinical trials (RCTs) demonstrated that thrombectomy is overwhelmingly superior to medical management for patients with emergent large vessel occlusion.2–6 Shortly thereafter, in 2016, the Society of Vascular and Interventional Neurology (SVIN) guideline writing committee published recommendations for appropriate hospital and individual requirements in order to demonstrate adequate expertise in thrombectomy.7 These recommendations were in part based on the Stroke Chain of Survival endorsed in the American Heart Association/American Stroke Association 2013 guidelines for the early management of patients with acute ischemic stroke.8 At that time, Joint Commission requirements for annual patient volume at comprehensive stroke centers (CSCs) included 20 patients with subarachnoid hemorrhage (SAH) and 25 patients with AIS treated with IV tissue plasminogen activator (tPA).

Given these Joint Commission recommendations for aSAH and IV tPA, the SVIN writing committee established a minimum requirement of 25–30 thrombectomy-treated patients per year. In addition, the SVIN recommendations also stated that each CSC neuroendovascular operator should complete a minimum of 10 mechanical thrombectomy procedures per year. In February of that year, a multi-society consensus document endorsed by the SVIN, SNIS, AANS, CNS, ASNR, AAFITN, ANZSNR, CING, ESNR, ESMINT, JSNET, SILAN, and WFITN was also published, which outlined training and education requirements as well as hospital resource requirements and quality assurance requirements, but did not specify specific physician or hospital volume requirements.9 These papers represent early and appropriate initial forays into defining what constitutes an appropriate threshold for establishing expertise. However, since those early days much has changed and the field has evolved.

There has been continued improvement in stroke systems of care and increased access to thrombectomy services, which has resulted in continued (~30%) annual increases in the number of thrombectomies performed according to national Medicare data. Furthermore, the relationship between procedural volume and thrombectomy quality has been strongly supported.10 11 This growing evidence led to the publication of an updated recommendation document in 2018, once again endorsed by multi-society consensus including SVIN, SNIS, ESO, WSO, ASNR, AAFITN, ANZSNR, CSNR, ESNR, ESMINT, JSNET, SILAN, and WFITN, which recommended that centers performing stroke thrombectomy should perform at least 50 such procedures annually and that individual physicians should perform at least 15 thrombectomies per year.12

This individual annual thrombectomy volume of 15 cases per year was also arrived at through consensus discussion and eventual recommendation by the Joint Commission Technical Advisory Panel (TAP) for Thrombectomy Capable Center certification. The Joint Commission TAP is a multispecialty effort which participated in robust discussion and stakeholder engagement before finally settling on this recommendation. As part of the robust national discussion regarding individual volume requirements, individual leaders of the SNIS, SVIN, and the AANS and CNS published a position statement in strong support of the 15 thrombectomy individual volume minimum.13

However, despite the strengthened correlations between volume and outcome, the multi-society endorsement of a minimum individual annual thrombectomy volume of 15 cases per year, and the Joint Commission’s independent arrival at the same conclusion, some individuals/organizations have attempted to refer to the outdated 2015 recommendation documents of the SNIS and SVIN as justification that the current 15 annual thrombectomy requirement is overly burdensome and excessive. In some ways this is not a surprise, which is why many leaders of the initial evidence-based RCTs anticipated an attempt to extrapolate the benefit demonstrated in those trials to low volume and low expertise centers/practitioners. As a result, they published an editorial warning the stroke community that the trials were performed at high volume centers with trained and experienced practitioners and that it would be an error to presume that the RCT results would be replicated in different circumstances.14

Given the confusion surrounding the 2016 papers, we—the leadership of the SNIS, SVIN, and the Joint Cerebrovascular Section of the AANS/CNS—have drafted this statement to clarify our societies’ position on this important matter. The SNIS, SVIN, and the Joint Cerebrovascular Section of the AANS/CNS support the individual annual thrombectomy volume requirement of 15 for all neurointerventionalists seeking to perform this procedure.

Over the last 4 years much has evolved in stroke care. Extensive evidence from thousands of patients, both from RCTs and real-life registries, demonstrate that thrombectomy reduces disability and saves lives. This evidence supports that this treatment be provided by adequately trained physicians who maintain appropriate procedural volume in order to ensure patients are provided their best chance for good outcomes. Stroke patients deserve access to appropriately skilled physicians.