Yes, one would expect that after 6 months of warfarin the pulmonary embolism would've been reabsorbed. Six months would be fairly standard. Factors that would influence whether it should be "life-long" include factors that contributed to the clot formation (ie. do you have a genetic tendency to develop clots such as Factor V deficiency or anti thrombin III deficiency, etc.) and whether this is your first clot or second, etc.