Analysis of risk factors of hemorrhagic transformation after acute ischemic stroke: cerebral microbleeds do not correlate with hemorrhagic transformation.

To study the potential risk factors including cerebral microbleeds (CMB) of hemorrhagic transformation (HT) after acute ischemic stroke. We included 348 consecutive patients with acute infarction who were hospitalized in two centers from June 2009 to December 2010. Acute ischemic infarctions were subdivided into atherosclerotic, cardioemblic, lacunar, and undetermined infarction groups. The related risk factors were recruited for analysis. All patients underwent gradient-echo T2-weighted imaging (GRE) to detect CMB and HT. Logistic regression analysis was used to analyze relationships, with HT as response variable and potential risk factors as explanatory variables. Multivariate logistic regression analysis demonstrated that predictor factors of HT were cardioembolic infarction (OR 24.956, 95 % CI 2.734-227.801, P = 0.004), infarction of undetermined causes (OR 19.381, 95 % CI 1.834-205.104, P = 0.014), and scores of NIHSS (OR 1.187, 95 % CI 1.109-1.292, P < 0.001), diabetes mellitus (OR 4.973, 95 % CI 2.004-12.338, P = 0.001). Whereas, the level of low-density lipoprotein was the protective factor (OR 0.654, 95 % CI 0.430-0.996, P = 0.048).The prevalence of CMB was 45.98 % (160/348) with no statistically difference among different subtypes. Thirty-five out of 348 (10.06 %) patients with ischemic stroke developed HT with a statistical difference among different subtypes of ischemia (χ (2) = 42.140, P < 0.001). The distributions of HI and PH among subgroups were variable with significant differences (χ (2) = 17.536, P = 0.001; χ (2) = 12.028, P = 0.007). PH frequency of cardioembolism was the highest (4/28, 14.29 %), and symptomatic ICH was also highest (7.14 %). The CMBs do not significantly correlate with HT. Knowledge of the risk factors associated with HT after ACI, especially HT following thrombolyitc therapy may provide insight into the mechanisms underlying the development of HT, helps to develop treatment strategy that reduces the risk of PH and implicates for the design of future acute ischemic stroke trials.