| Part One:Risk factors for new cerebral microbleeds after intravenous thrombolysisObjective:The current study aimed to determine the frequency and risk factors of new cerebral microbleeds (CMBs) after intravenous thrombolysis in acute ischemic stroke patients by using contiguous thin-slice susceptibility-weighted imaging (SWI), and investigated its influence on hemorrhagic transformation and clinical functional outcome.Methods:We retrospectively reviewed our prospectively collected database for consecutive patients with acute ischemic stroke received thrombolytic therapy. We then enrolled patients who underwent SWI before and 24 hours after intravenous thrombolysis. We evaluated hemorrhagic transformation on follow-up scans, and the clinical functional outcome by modified Rankin Scale (mRS) score after 3 months. New CMBs were defined as CMBs that newly appeared on the follow-up SWI compared with the initial scans. Logistic regression analyses were used.Results:Of the included 145 remaining patients,51 (35.2%) were women, with a mean age of 67±13 years. Baseline CMBs were observed in 68 patients and 10 new CMBs in 7 patients. Multiple regression analysis indicated that baseline infarct volume (odds ratio 1.698 per 10 ml; 95% CI:1.107 to 2.419; p=0.038) and systolic blood pressure (odds ratio 2.059 per 10 mmHg; 95% CI:1.116 to 3.742; p= 0.031), but not the presence of baseline CMBs, were independently associated with new CMBs. The frequency of any hemorrhagic transformation was not different between patients with and without new CMBs (57.1% VS 28.3%; p= 0.28). The presence of new CMBs didn’t predict functional outcome (odds ratio 0.448; 95% CI:0.069 to 4.266; p= 0.528).Conclusion:New CMBs developed rapidly 24 hours after intravenous thrombolysis. The significance of these new CMBs and their effect on cognitive and functional outcome merits further investigation.Part Two:Effect of cerebral microbleeds on intravenous thrombolysis in acute ischemic stroke patientsObjective:Thrombolysis-related hemorrhagic transformation subtypes may have different prognostic implications. We aimed to analyze the impact of CMBs burden on hemorrhagic transformation subtypes and functional outcome after intravenous thrombolysis.Methods:We retrospectively reviewed our prospectively collected database for consecutive patients with acute ischemic stroke received thrombolytic therapy. We then enrolled patients who underwent SWI before intravenous thrombolysis. We evaluated hemorrhagic transformation on follow-up scans, and the clinical functional outcome by mRS score after 3 months. Logistic regression analysis was used to determine the impact of CMBs on hemorrhagic transformation subtypes and functional outcome.Results:Of the included 449 remaining patients,151 (33.6%) were women, with a median age of 67 years (mean 66±13 years, range 23-94 years). Mean time from onset to intravenous thrombolysis was 229±103 minutes. We observed 934 CMBs in 172 patients (38.3%) on initial SWI scans. Hemorrhagic transformation occurred in 138 patients (30.7%). Logistic regression analysis indicated that the presence of extensive (≥3) CMBs was independently associated with parenchymal hemorrhage (PH) (odds ratio 6.808; 95% CI:2.227 to 20.817; p=0.001) and poor clinical outcome (odds ratio 2.340; 95% CI:1.086 to 5.043; p=0.030).Conclusion:The presence of extensive (>3) CMBs increased the risk of PH 24 hours after intravenous thrombolysis, and predicted poor clinical outcome independently. Future prospective studies with much larger sample sizes are required to clarify our results, and standardization of imaging parameters for CMBs detection across centers is encouraged.Part Three:Safety of prior antiplatelet use in patients with cerebral microbleeds receiving intravenous thrombolysisObjective:With the development of magnetic resonance imaging, CMBs has become a major concern in antiplatelet therapy decision making. This study aimed to investigate the effect of prior antiplatelet use on hemorrhagic transformation and functional outcome after intravenous thrombolysis in patients with CMBs.Methods:We retrospectively reviewed our collected clinical and radiologic data from consecutive acute ischemic stroke patients who have received SWI and intravenous thrombolysis. The presence of CMBs, record of prior antiplatelet use, hemorrhagic transformation subtypes according to ECASS II criteria and functional outcome based on mRS at 3 months were analyzed in logistic regression model.Results:Of the included 449 remaining patients, the mean age was 66±13 years,151 (33.6%) were women, time frome onset to intravenous thrombolysis was 229±103 minutes. A total of 934 CMBs were detected in 172 (38.3%) patients, among whom 63 (14.0%) received prior antiplatelet agent. Logistic regression analysis indicated that prior antiplatelet use increased neither risk of PH (OR= 0.809,95%CI 0.201-3.262, p=0.766) nor bad functional outcome (OR=1.517,95%CI 0.504-4.568, p=0.459) in patients with CMBs, whereas in patients with extensive (>3) CMBs prior antiplatelet use increased risk of extraischemic hemorrhage (OR= 9.737,95%CI 1.364-69.494, p=0.023) but not bad functional outcome (OR= 1.697,95%CI 0.275-10.487, p=0.569).Conclusion:Even in patients with CMBs, thrombolytic treatment should not be excluded due to the prior use of antiplatelet based on the present evidence. Future larger prospective study are needed for patients with extensive (≥3) CMBs. |
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