What steps can you take to avoid stroke after breast reduction?

I'm a little unclear as to your question. A stroke is a development of a blood clot in the brain. Some types of surgery increase the risk of stroke (e.g. carotid endarterectomy), but most operations do not. The type of blood clot we worry about after surgery is called a deep-vein thrombosis, or DVT. This is a clot that forms in the deep veins in your legs. The danger is that the clot can dislodge and travel to your lungs, damaging the lung tissue. This is called a pulmonary embolus.  The risk of DVT increases with long immobilizations. Surgery certainly increases the risk, but so do long plane or car rides. This is something that your surgeon will discuss with you as part of the risks of surgery. Generally speaking, DVTs are exceedingly rare in a healthy patient undergoing breast reduction surgery.