Blood clots. A blood vessel could possibly be blocked by an embolus. This can be a tiny mass of particles that moves in the bloodstream. Or it may be blocked by a thrombus. It is a blood clot. Carotid artery condition: A blockage or narrowing during the arteries supplying your brain. https://www.sgvascularctr.com/a-comprehensive-approach-to-lymphoedema-treatment-a-vascular-surgeons-perspective/