Estimating stroke risk in AF

Accurate assessment of stroke risk in the setting of AF is very important, as it determines whether or not anticoagulation is indicated.  The current tool most used is CHADS-VASC. But there are others, and if stroke risk is related more toatrial dysfunction than to AF itself, assessment of atrial function will take on greater importance.

If atrial dysfunction is a primary cause of emboli, how can we best evaluate the status of the atrium (echo parameters of LA size and function, bnp, troponins, mri)?  Could an assessment of atrial function be used to better risk stratify patients for anticoagulation, better than or in addition to CHADS-VASC?  Are other tools superior to CHADS-VASC?

Is there any role for CHADS-VASC or tools evaluating atrial function in patients without a history of AF?  To target patients for screening for AF or even to consider anticoagulation in the absence of AF?