hemorrhagic transformation ( ht ) of ischemic stroke ( is ) is a relatively frequent complication occurring in 2.2% to 44% of clinical cases ( 1 ) . ht is related to poor prognosis of patients with is . additionally , it is one of the main obstacles for on time initiation of thrombolytic therapy ( 2 ) . some known risk factors for ht suggested by previous studies are severity of is , old age , history of diabetes mellitus , the time to reperfusion , thrombolytic therapy , use of aspirin and other anticoagulant drugs ( 1,3,4 ) . recent studies revealed that the serum ferritin level could be a novel predictor for ht ( 5,6 ) . experimental studies supported the effect of iron overload in the ischemic brain and endothelium damage . iron intake was associated with the larger size of infarction , higher oxidative stress and more inflammatory response in is model of rats ( 7 ) . iron depletion or chelation decreases the size of infarction , brain edema and neurological deficits in the cerebral ischemic - reperfusion experimental models ( 8,9 ) . a few clinical evidences exist in favor of this issue . in patients with is , who were not treated by thrombolytic therapy , the high serum level and cerebrospinal fluid  ( csf ) level of ferritin were associated with poor neurological outcome and larger size of infarction ( 10 - 12 ) . in another study on patients with is , it was found that high serum ferritin level can be an important predicting factor for ht . this study suggested that the serum ferritin level of greater than 164.1ng / ml could be an independent predicting factor for ht with 85% sensitivity and 75% specificity ( 6 ) . furthermore , in a research on the is patients treated by intravenous  recombinant tissue plasminogen activator  ( rtpa ) , high serum ferritin level was concluded as a predictor for symptomatic ht and severe brain edema ( 5 ) . considering the important role of ht in mortality and morbidity of is patients ( 6 ) and lack of sufficient clinical researches to evaluate serum ferritin level as a predictor of ht , this cohort study was conducted to examine the association between serum ferritin level and ht of is . this prospective cohort study was conducted on patients with acute massive ischemic stroke ( is ) of middle cerebral artery admitted within 24 hours after their symptoms onset at the stroke unit of firoozgar general hospital in tehran during april 2012 and february 2014 . the patients with acute massive is of middle cerebral artery were included in this research . acute massive is was defined as acute obstruction of the stem of middle cerebral artery which results in ischemia of more than 30% of the middle cerebral artery territory . they were divided into two groups based on serum ferritin level greater or lower than 164.1ng / ml . this cut off has been suggested in previous studies ( 6 ) . patients with the following conditions were excluded from the study : patients with a history of conditions that may have influenced the serum ferritin level including liver disease , chronic inflammatory conditions ( rheumatoid arthritis , inflammatory bowel disease and bacterial infections ) , malignancy , thyrotoxicosis and alcohol consumption more than 40g / day ; cases expired in the first 24 hours of admission ; and patients under treatment for diseases related to iron . the medical ethics committee of iran university of medical sciences and firoozgar clinical research development center ( fcrdc ) approved this study . all cases who participated in the study provided informed consent . in case of patients with low level of consciousness , demographic characteristics and baseline data of the patients including age , sex , history of medical conditions ( stroke , diabetes mellitus and hypertension ) , history of smoking , history of alcohol consumption , drug history of anti - platelet therapy and primary clinical signs at admission ( systolic blood pressure , diastolic blood pressure and body temperature ) were collected from the medical records in check lists filled by neurology residents in the emergency unit and in the stroke unit of firoozgar general hospital . within 24 hours of admission , the patients blood samples were sent to the laboratory to examine the serum ferritin level and prothrombin time and platelet count . all patients were diagnosed with brain computed tomography ( ct ) scan at the time of admission and followed for ht by repeating brain ct scan on the first and fifth days of admission , and each time a significant change was observed in the clinical condition of the patients during the two- week follow up . all brain ct scans were interpreted by one radiologist for diagnosing ht , which was defined as any hyper density changes in the stroke area . to evaluate the etiology of stroke , all patients were treated based on the american stroke association guideline ( 15 ) for acute is . prevalence rate and mean as central indices and standard deviation ( sd ) as an index of dispersion were used to describe the qualitative and quantitative variables . all tests hypotheses were two- tailed , and the probability - value of less than 0.05 was considered statistically significant . this prospective cohort study was conducted on patients with acute massive ischemic stroke ( is ) of middle cerebral artery admitted within 24 hours after their symptoms onset at the stroke unit of firoozgar general hospital in tehran during april 2012 and february 2014 . the patients with acute massive is of middle cerebral artery were included in this research . acute massive is was defined as acute obstruction of the stem of middle cerebral artery which results in ischemia of more than 30% of the middle cerebral artery territory . they were divided into two groups based on serum ferritin level greater or lower than 164.1ng / ml . this cut off has been suggested in previous studies ( 6 ) . patients with the following conditions were excluded from the study : patients with a history of conditions that may have influenced the serum ferritin level including liver disease , chronic inflammatory conditions ( rheumatoid arthritis , inflammatory bowel disease and bacterial infections ) , malignancy , thyrotoxicosis and alcohol consumption more than 40g / day ; cases expired in the first 24 hours of admission ; and patients under treatment for diseases related to iron . the medical ethics committee of iran university of medical sciences and firoozgar clinical research development center ( fcrdc ) approved this study . all cases who participated in the study provided informed consent . in case of patients with low level of consciousness , demographic characteristics and baseline data of the patients including age , sex , history of medical conditions ( stroke , diabetes mellitus and hypertension ) , history of smoking , history of alcohol consumption , drug history of anti - platelet therapy and primary clinical signs at admission ( systolic blood pressure , diastolic blood pressure and body temperature ) were collected from the medical records in check lists filled by neurology residents in the emergency unit and in the stroke unit of firoozgar general hospital . within 24 hours of admission , the patients blood samples were sent to the laboratory to examine the serum ferritin level and prothrombin time and platelet count . all patients were diagnosed with brain computed tomography ( ct ) scan at the time of admission and followed for ht by repeating brain ct scan on the first and fifth days of admission , and each time a significant change was observed in the clinical condition of the patients during the two- week follow up . all brain ct scans were interpreted by one radiologist for diagnosing ht , which was defined as any hyper density changes in the stroke area . to evaluate the etiology of stroke , all patients were treated based on the american stroke association guideline ( 15 ) for acute is . data were analyzed using spss software 21 . prevalence rate and mean as central indices and standard deviation ( sd ) as an index of dispersion were used to describe the qualitative and quantitative variables . all tests hypotheses were two- tailed , and the probability - value of less than 0.05 was considered statistically significant . thirty patients with massive is of middle cerebral artery admitted in the stroke unit of firoozgar general hospital were enrolled . they were divided into two groups : 15 cases in the group with serum ferritin level of greater than 164.1ng / ml ( group a ) , and 15 with serum ferritin level of lower than 164.1ng / ml ( group b ) . n ( % ) : the group with serum ferritin level > 164.1 
 
 * * n ( % ) : the group with serum ferritin level < 164.1 
 
 * mean and ( sd ) : the group with serum ferritin level > 164.1 
 
 * * mean and ( sd ) : the group with serum ferritin level < 164.1 
 
 according to this table , the comparison of all baseline characteristics between the two groups was not statistically significant ( p>0.05 ) . after the two - week follow up , ht was observed in eight cases ( 53.3% ) of group a and in two cases ( 13.3% ) of group b. the difference between the incidence rates of ht was statistically significant in the two groups ( p=0.020 ) . the relative risk ( rr ) of ht was 4 ( 95% ci : 1.012 - 15.8 ) in the patients with massive is of middle cerebral artery and serum ferritin level upper than 164.1ng / ml . this study vigorously supported a few previous clinical studies , which had shown the association between serum ferritin level and hemorrhagic transformation ( ht ) of ischemic stroke ( is ) . a significant difference was found between the incidence rates of ht in the two groups , which were separated , based on the serum ferritin level greater or lower than 164.1ng / ml . the relative risk of ht of is was estimated 4 ( 95% ci 1.012 - 15.8 ) in the patients with serum ferritin level of greater than 164.4ng / ml in this study . the experimental studies revealed the role of increased iron in the stress oxidative reactions , inflammatory responses and vascular endothelium damage in the ischemic brain ( 7 - 9 ) . castellanos m et al . demonstrated that the increase in the iron intake was associated with the increase of extent of infarction after obstructing the middle cerebral artery of rats ( 7 ) . in the studies on the experimental cerebral ischemic - reperfusion models of the dogs and gerbils by davis s et al . and patt a et al . in separate studies , it was concluded that the group treated by iron chelator drug had lower complications of brain ischemia ( 8 - 9 ) . the results of our study were clinically compatible with those of the mentioned experimental studies . a small number of clinical assessments were found in the literature review , probing the relationship between serum ferritin level as an indicator of tissue iron store ( 13,14 ) , and one of the most important complications of is : ht . some clinical studies illustrated that the high serum ferritin level in the patients with is at the first 24 hours of admission was related to the severity of stroke , increase of size of the lesion and poor prognosis ( 10 - 12 ) . however , the effect of serum ferritin level on ht was not determined in these studies . and lindley ri found some risk factors of ht including old age , history of diabetes mellitus , the extent of infarction , drug history of anti - platelet medications and thrombolytic therapy ( 3,4 ) . we included the patients with massive is of middle cerebral artery and evaluated all the risk factors at the baseline data gathered from the patients . choi kh et al . in a study on 752 patients with is addition to introducing serum ferritin level as an important predicting factor of ht , suggested 164.1ng / ml as a cut off for serum ferritin level ( or=4.993 ) ( 6 ) . notably , considering the retrospective analytical nature of that study , the results of our prospective cohort research were more confirmatory . moreover , in another investigation by millan m et al . , increased body iron stores were associated with poor outcome after the thrombolytic treatment in acute is ( 5 ) . in this study , four patients were treated with thrombolytic therapy , though their frequencies were not significantly different between the two groups . 
 
 small sample size and short time of the follow up were weak points of this study . furthermore , because ferritin is an acute phase reactant , so many confounding conditions influence its serum level ( 6 ) . hence , impossibility of eliminating all factors affecting serum ferritin level in spite of our maximum efforts , limits the interpretations of our findings . conducting multi - centric studies with long - term follow - ups and larger sample sizes is highly recommended . our study confirmed the findings of previous studies , which found that serum ferritin level was a predicting factor for ht of is . consequently , the serum ferritin level of greater than 164.1ng / ml in the first 24 hours after admission of the patients with acute is can be considered as a red flag to gain more attention when managing these patients , particularly during anticoagulant and thrombolytic therapy . the effect of interventions on reducing the serum ferritin level , such as phlebotomy and iron chelator medications , can be the subject of additional studies in the future .
background : hemorrhagic transformation ( ht ) of ischemic stroke ( is ) is a detrimental complication . 
 this 
 study investigated the association between serum ferritin level and ht in patients with massive is of middle 
 cerebral artery . 
 methods : thirty patients with massive is of middle cerebral artery were enrolled in this prospective cohort 
 study . 
 they were divided into two groups based on the serum ferritin level , lower or greater than 164.1ng / ml at 
 the first 24 hours after admission . to investigate the incidence of ht in the two groups , we observed them for 
 two weeks . 
 results : during the two- week observation , the incidence of ht was two persons ( 13.3% ) in the group with 
 the serum ferritin level of lower than 164.1ng / ml , and eight persons ( 53.3% ) in the other group . 
 this difference 
 was statistically significant between the two groups ( p=0.02 ) . 
 the relative risk of ht was 4 ( 95% ci : 1.012- 
 15.8 ) in the patients with massive is of middle cerebral artery and the serum ferritin level greater than 
 164.1ng / ml . 
 conclusion : this study revealed that the serum ferritin level greater than 164.1ng / ml in the first 24 hours after 
 admission is a reasonably important predictor for ht of is . 
 conducting studies on factors affecting the serum 
 ferritin level are suggested .