Table 3

Challenges and possible solutions when conducting an endovascular treatment trial for medium vessel occlusion strokes

ProblemExplanationPossible solution
Technique and technology related
 Lack of appropriate devicesCurrent treatment devices are not tailored towards MeVOs and are 'relatively oversized'. This might increase the risk of iatrogenic complicationsDevelopment of smaller devices that are optimized for MeVO thrombectomy
 Inability to detect MeVOsAccurate and reliable detection of MeVOs can be challenging for less experienced physicians, particularly on single phase CT angiography

  1. Multiphase CT angiography, color coded multiphase CT angiography maps, CT perfusion

  2. Automated occlusion detection

Training related
 Lack of skill/expertiseNeurointerventional expertise in low volume centers might not be sufficient to routinely offer safe and responsible EVT treatment for MeVOs

  1. Centralization of neurointerventional stroke care

  2. Simulation enhanced training program

Lack of appropriate outcome assessment tools
 Lack of granularity of current outcome measurement scalesEstablished outcome measurement scales for acute stroke such as the mRS and NIHSS scales may not adequately capture subtle clinical deficits and symptoms

  1. 'Excellent clinical outcome' (mRS 0–1) as an alternative outcome. However, with a limited dataset available, calculation of sample size is difficult.

    Development of an alternative MeVO scale; however, it takes a lot of time to validaten a new scale, and widespread acceptancemight not be given

  2. Increased sample size to compensate for potential lack of distinction between treatment and control group due to lack of granularity

Emerging alternative medical treatment options
 Development of alternative medical treatment optionsAlternative lytic agents with increased efficacy such as intravenous tenecteplase16 may reduce the need for EVT in MeVO patientsInclusion criteria that ensure that only patients who are ineligible for intravenous treatment or in whom this treatment failed are enrolled

  • EVT, endovascular treatment; MeVO, medium vessel occlusion; mRS, modified Rankin score; NIHSS, National institutes of Health Stroke Scale.