Lumbar sympathetic block is an analgesic procedure frequently performed in chronic pain clinics for ischemic lower limb pain from peripheral arterial disease. Although the lumbar sympathetic ganglia are anatomically near major vascular and neural structures, complications such as severe hemorrhage is rarely reported. Aspirin/extended release dipyridamole (Aggrenox) is indicated for secondary stroke prevention. Stroke is frequently a co-morbid condition in patients with peripheral vascular disease. Interventional pain physicians frequently face the difficulty of deciding whether to continue or stop antithrombotic medications in the periprocedural period because of the devastating consequences of both hemorrhagic and thrombotic complications. Due to a paucity of data, no guidelines have been specifically written for interventional procedures for chronic pain. To aid future decision making, we present a case report of psoas hematoma developed after lumbar sympathetic block in a patient with end stage renal failure and hepatic dysfunction who had limb-threatening ischemia. The patient was treated with Aggrenox until three days before the procedure.