Mechanical thrombectomy for ischaemic stroke

Update September 2020

Training of interventional radiologists

With regard to a consultant interventional radiologist training to provide a mechanical thrombectomy (MT) service, the RCR, the British Society of Interventional Radiology (BSIR), the British Society of Neuroradiologists (BSNR) and UK Neurointerventional Group (UKNG) continue to support the supplementary agreement that was published in 2017 and would advise that the following high-level requirements are in-place for any local interventional radiology (IR) training arrangement:

  1. Training occurs in one or more neuroscience centres
  2. Training includes: clinical neuroscience knowledge, advanced neurovascular imaging capabilities and MT procedural skills (while training for MT, it is expected that IRs will experience a range of interventional neuroradiology (INR) techniques, including, but not restricted to, aneurysm coiling and managing complications)
  3. Sign-off for completion of MT training would require one INR and the medical director of the principal training hospital (both registered with the GMC). It is advised that specific competencies would be approved by a range of suitably qualified people (including more than one GMC Registered INR) through the stages of training.
  4. Governance measures would be required to ensure maintenance of operator competencies (local) and audit of patient outcomes (national)

Credential in Interventional Neuroradiology (Acute Stroke)

The project board convened to develop a credential has produced a comprehensive document detailing the proposed training pathway. It was submitted to the GMC at the end of 2019 and is currently pending their approval. This process has been delayed due to a combination of COVID19 and ongoing discussions concerning the exact scope of the credential. We hope to be able to announce their approval and a timescale for implementation soon.


Specialised commissioners in England have given approval to fund 24/7 services to deliver mechanical thrombectomy (MT) as an effective treatment for ischaemic stroke caused by large vessel occlusion.

The current workforce

Only interventional neuroradiologists (INRs) are currently able to provide this service in neuroscience centres (24 in England, 28 across the UK). INR staffing levels vary between centres (ranging from 0-5) and currently only one centre in England is staffed to provide 24/7 cover for MT.

The current number of fully-trained INRs in the UK would need to almost double to approximately 150 to meet the service expansion needed to provide 24/7 MT services and the number of radiology trainees currently training to receive a CCT in interventional radiology sub-specialising in INR is insufficient to meet this demand.

Training to deliver mechanical thrombectomy

In order to achieve the desired delivery of a 24/7 service in MT across England, the number of operators capable of contributing to MT services needs to expand more rapidly than will be achieved by current INR trainee numbers. This means training other specialists to perform MT.

The British Society of Neuroradiologists (BSNR) has produced “Training guidance for mechanical thrombectomy” (Lenthall R, McConachie N, White P, Clifton A, Rowland-Hill C. BSNR training guidance for mechanical thrombectomy. Clin Radiol 2017; 72(2): 175.e11–175.e18.) which details the training that will be required for practitioners from different clinical backgrounds to achieve the necessary skills and experience to effectively contribute to the acute stroke service. This guidance will underpin all routes to increasing the workforce.

Increasing the workforce

There are two clear routes to achieving the necessary INR workforce expansion:

1. Trained interventional radiologists

Consultant interventional radiologists already have many of the skills required to perform MT, such as prior experience of image interpretation and familiarity with using catheters. Their previous training and experience should therefore facilitate more rapid training in MT than for those from different clinical backgrounds. In order to facilitate and support this training The Royal College of Radiologists, the BSNR, the British Society of Interventional Radiology (BSIR) and the UK Neurointerventional Group (UKNG) have worked together to produce “Supplementary guidance to facilitate the training of interventional radiology (IR) consultants to undertake stroke thrombectomy”.

This supplementary guidance only applies to consultant interventional radiologists who have undertaken a period of training in a range of diagnostic and interventional radiology practice culminating in the FRCR and a period of post-FRCR training in IR, or IRs who have demonstrated similar levels of training, experience and qualification by equivalence. 

While it is hoped that significant numbers of interventional radiologists will opt to undertake this additional training it is unlikely that this route alone will completely address the shortage of qualified operators in the short to medium term. Therefore a second option is also being pursued.

2. INR credential for clinicians from non-IR or INR backgrounds

Multidisciplinary discussions, convened by the College, with representation from all interested specialty groups including: radiologists, stroke physicians, neurologists, neurosurgeons and cardiologists, have led to a consensus to begin development of an INR credential focused on acute stroke. The aim of this credential will be to enable clinicians from other specialty backgrounds, to train in the broad skills of INR and learn to perform MT for acute stroke and other interventions such as coiling intracranial aneurysms.

After such training, it is anticipated that doctors with the credential would join INR teams and contribute to 24/7 services providing MT for acute stroke and the coiling of intracranial aneurysms. Enabling such training for clinicians from other specialty backgrounds in the UK, would also align with practice in Europe and North America.

Further information will be posted here as the work progresses.  If you have any questions please contact credentials@rcr.ac.uk