Anemia and stroke: Where do we stand?

Anemia seems to have a clear relationship with cerebrovascular events (CVEs), as there is a direct connection between central nervous system, blood supply, and tissue oxygen delivery. Anemia is considered a hyperkinetic state which disturbs endothelial adhesion molecule genes that may lead to thrombus formation. Furthermore, blood flow augmentation and turbulence may result in the migration of this thrombus, thus producing artery-to-artery embolism. It is for this reason that anemia is characterized as "the fifth cardiovascular risk factor." Anemia is consistently present in patients with acute stroke, ranging from 15% to 29%, while the mortality rate was significantly higher in patients suffering from anemia at the time of admission. Different types of anemia (sickle cell disease, beta thalassemia, iron deficiency anemia [IDA]) have been associated with increased cardiovascular and CVE risk. The relation between hemoglobin level and stroke would require further investigation. Unfortunately, treatment of anemia in cardiovascular and cerebrovascular disease still lacks clear targets and specific therapy has not developed. However, packed red blood cell transfusion is generally reserved for therapy in patients with CVEs. What is more, treatment of IDA prevents thrombosis and the occurrence of stroke; although iron levels should be checked, chronic administration favors thrombosis. Regarding erythropoietin (EPO), as there is lack of studies in anemic stroke patients, it would be desirable to utilize both neuroprotective and hematopoietic properties of EPO in anemic stroke patients. This review aims to clarify the poorly investigated and defined issues concerning the relation of anemia and CVEs.