AHA/ASA volunteer expert Larry B. Goldstein, M.D. offers perspective (via Skype) on ISC 19 abstract 9.  He is the Ruth L. Works Professor, the Chairman of the Department of Neurology and Co-Director of the Kentucky Neuroscience Institute in Lexington, KY.
copyright American Heart Association 

"And this is the first real data that we're seeing associating e-cigarette use with hard cardiovascular events. But it's quite a concern, especially since nationwide now we've seen a leveling off in, and in many instances an increase in the risk of stroke-related mortality in the country. It's hard to know what contribution this has to that, but it doesn't appear to be safer, or safe right now from the data that's available."