About 9,000 stroke patients a year are missing out on a treatment that can prevent disability following a stroke, say UK experts.
Clot retrieval can restore blood flow to the brain, preventing some lasting damage, but currently only 600 patients a year get this therapy, they estimate.
A national stroke audit reveals part of the problem is a lack of skilled staff to do the procedure.
NHS England says stroke patients are receiving high quality care.
During a stroke, the blood supplying vital parts of the brain is interrupted.
The most common reason is a clot blocking a major blood vessel in the head, although some strokes are caused by a bleed.
The longer a part of the brain is starved of blood, the more likely lasting damage – such as paralysis and speech problems – will occur.
While many people with a stroke caused by a clot currently get drugs to help dissolve the blockage, this does not always work completely.
Thrombectomy – or clot retrieval – is another method, which aims to remove the clot mechanically.
It is a highly skilled operation, and stroke services need to be set up to be able to deliver the treatment.
A thin metal wire housing a mesh is inserted into a major artery in the leg and, under X-ray guidance, it is directed to the site of the problem in the brain.
The mesh is then expanded, like a miniature fishing net, to trap and remove the clot.