No. Methadone does not cause strokes.
Hi
There was a case in either Norway or Sweden I think where a guy on methadone died of a stroke. There was a lot more going on there than methadone use tough.
He was using both methadone and heroin, blacked out on the floor, got rhabdo (muscle death) due to the bruising, causing a clot which caused a stroke.
The recommendation from the paper in that medical journal was to inform all methadone users of the risk of stroke.
Personally I think the risk of stroke, directly related to methadone is fantastically small.
hope this helps.