Advised recent data suggest medication management may be as successful as carotid endarterectomy surgery stroke prevention with 50%occluded,but where?

ASA: The American Heart and Stroke Association have the best evidence based guidelines available for this type of thing. Some of which you can review at their website.

Cochrane Reviews: As of 2011 Carotid Endarterectomy was of marginal benefit in those with Stenosis 50%-69% and of no greater benefit in Stenosis 30-49% ... see http://www.ncbi.nlm.nih.gov/pubmed/21491381?dopt=Abstract Putting Endarterectomy into the search engine at http://onlinelibrary.wiley.com/ gives recent data. Give most weight to a Systematic Review.. Do note most of the Stenoses under study are are >70%.