Recurrence of ischemic stroke may be related to chronic hemodynamic failure of the brain. Long-term changes in cerebral blood flow (CBF) remain undetermined for each ischemic stroke subtype. We performed the present study to clarify this issue. The study group consisted of 77 unilateral, hemispheric, ischemic stroke patients who had a single stroke episode; atherothrombotic stroke in 34, cardioembolic in 26 and lacunar in 17. We measured baseline CBF in the affected and unaffected hemispheres 1.0-3.4 months after stroke onset, then repeated the measurements 10 months to 10 years later (mean 43.7 months), with the xenon-133 inhalation method. We analyzed changes in CBF in relation to other clinical characteristics. CBF in the affected hemisphere changed differently among the stroke subtypes (P < 0.01); increased in the atherothrombotic group, particularly within 40 months of stroke; remained unchanged in the cardioembolic group; and decreased in the lacunar group, especially later than 40 months of stroke. In the atherothrombotic group, CBF increased in hypertensive patients but decreased in normotensives (7.9 +/- 2.4% and -3.6 +/- 3.9%, respectively; P < 0.05). Present results suggest that long-term changes in CBF depend on ischemic stroke subtype. Development of collateral circulation may occur after several years in atherothrombotic stroke patients. The findings raise doubts about the significance of chronic hemodynamic failure as a cause of stroke recurrence.