Operating on low grade stenosis (even if symptomatic) may lead to more complications than future stroke prevention. Have a look at the following link:

mrw.interscience.wiley.com/cochrane/clsysrev/articles/CD001081/frame.html  

By the way, thanks for the quick referral. Although carotid endarterectomy is not appropriate in this case, it is important that we see these patients within two weeks of their first symptoms.

Check out the following articles:

Rothwell PM et al. Endarterectomy for symptomatic carotid stenosis in relation to clinical subgroups and timing of surgery. Lancet 2004; 363:915

Fuster V et al. Task force report: ACC/AHA/ESC guidelines for the management of atrial fibrillation. Eur Heart J 2001;22:1852-923