Grounds for a medical lawsuit?

It's all very unfortunate, and my best wishes to your mother, but I don't see how there has been any malpractice here. The wrong size stent was sent - administrative -up, these things happen. The machine broke - what were they supposed to do about that? The only odd thing is having to wait three days with no explanation, but they may have a very good reason. You wont win unless it's proven your mum wouldn't have had a stroke had the stent been fitted sooner, which I'm not sure will be possible, especially since she stroked after it was eventually fitted.