A method of reducing or blocking blood to a selected blood vessel or a selected part of the wall thereof, particularly for treating an aneurysm, an arteriovenous or dural malformation in a blood vessel, or for devascularizing tumors, by deploying in the blood vessel an expandable member having a contracted condition for manipulation within the blood vessel, and expandable to an expanded condition in the blood vessel for reducing or blocking blood flow through the selected part thereof, thereby promoting coagulation of blood therein, and for preventing thrombus material from being swept downstream, and applying a local stimulus to the interior of the malformation effective to initiate or accelerate coagulation of blood therein. In some described embodiments, the expandable member is a permeable mesh-like tube of biocompatible material, and in other described embodiments, the expandable member is an inflatable balloon.