Only recently, I found out that a bilateral carotid artery stenosis and a left vertebral artery occlusion was found. No surgeon was consulted, the patient was put on low dose aspirin, and sent home. No neurologic symptoms occured later. Your comments, please. It would be nice if the world would all fit into prospective, double blind, randomized clinical trials, but it doesn't.
Some clinical questions are difficult or impossible to study in that manner.
Soetimes even case comparisons are not practical, particularly with relatively rare conditions. So we have to resort to extrapolation of principles derived from other clinical scenarios. It is imperative, of course, if we wish to call it science, that the principles be placed in the context of a scientific theory, whose objects are derived from observations. Anticoagulation can reduce the extent of propagation of clot, even in the presence of stagnat flow. When clots mature they adhere and become less likely to propagate or embolize.