Cerebral thrombosis in patients with β-thalassemia: a systematic review

A hypercoagulable state has been documented in patients with β-thalassemia. It could result in thromboembolic events in several organs including brain involvement, which deserves particular attention. We summarized the prevalence of cerebral involvement in patients with β-thalassemia worldwide. We conducted an electronic search on PUBMED (MEDLINE), SCOPUS, and Google Scholar databases up to January 2011. Overall 152 thalassemic patients with cerebral thromboembolic events and a proportion of 1.13% (134 of 11770) were recorded. From all patients with cerebral thromboembolic events, 74 (48%) were splenectomized. Cerebral thromboembolic events were reported after transfusion in six β-thalassemia major, and two β-thalassemia intermedia patients. Three β-thalassemia major patients had irregular transfusion and 22 β-thalassemia intermedia patients were not transfused. Thrombocytosis were determined in 11 β-thalassemia major, and 15 β-thalassemia intermedia patients. Cardiomyopathy was present in 13 β-thalassemia major and four β-thalassemia intermedia patients. Also, nine β-thalassemia major patients had diabetes. Activated protein C resistant, decreased protein C or protein S or plasminogen level was detected in eight β-thalassemia major patients. Cerebral involvement appears to be associated with increasing age, transfusion naivety, splenectomy, thrombocytosis, intensive transfusion, decreased protein C level, and having risk factors for cerebrovascular accident such as cardiomyopathy, and diabetes. In light of these findings, diagnostic MRI is recommended in high-risk groups to screen for early asymptomatic brain damage. If brain ischemia is found, the administration of antiplatelet aggregants or blood transfusion is likely to be beneficial. In addition, in thalassemic patients who complicated with a thromboembolic event, secondary prophylaxis could be helpful to prevent cerebral thromboembolic events.