Objective:To investigate the correlation of blood pressure variability within 24 h after thrombolysis with symptomatic intracerebral hemorrhage (sICH) and 90 d outcome in patients with acute ischemic stroke.Methods:Patients with acute ischemic stroke treated with recombinant tissue plasminogen activator in the Department of Neurology, Jinshan Branch, Shanghai Sixth People's Hospital from January 2017 to May 2019 were enrolled prospectively. The baseline data of the patients were collected. The patients were divided into sICH group and non-sICH group according to the changes of head CT and the National Institutes of Health Stroke Scale (NIHSS) score after thrombolysis. At 90 d after thrombolysis, the modified Rankin scale was used to evaluate the outcomes, and the patients were divided into a good outcome group (0-2) and a poor outcome group (3-6). The blood pressure within 24 h after thrombolysis was monitored and the parameters related to blood pressure variability in 5 time periods (0-2 h, 2-6 h, 6-12 h, 12-18 h, and 18-24 h) were calculated, including systolic blood pressure (SBP) and diastolic blood pressure (DBP) maximum (max), minimum (min), maximum and minimum difference (max-min) and mean (mean). The differences between the adjacent blood pressures were calculated, the standard deviation (SD), successive variation (SV), rise successive variability (SVrise), drop successive variability (SVdrop), the maximum squared difference in blood pressure rise (SVrisemax), the maximum squared difference in blood pressure drop (SVdropmax) were calculated and recorded, respectively. Multivariate logistic regression analysis was used to evaluate the effect of various blood pressure variability parameters on sICH and the outcomes after intravenous thrombolysis. Results:A total of 112 patients receiving intravenous thrombolysis were included in the study. Their median age was 71 years (range, 38-92 years), 66 were males (58.9%); median baseline NIHSS score was 10. Seventeen patients (15.2%) developed hemorrhagic transformation, 10 of them (8.9%) were sICH. The 90-d follow-up showed that 73 patients (65.2%) had a good outcome, 39 (34.8%) had a poor outcome and 7 of them (6.3%) died. There were significant differences in hypertension ( P=0.029), ischemic heart disease ( P=0.012), total cholesterol ( P=0.033), baseline NIHSS score ( P=0.003) between the sICH group and the non-sICH group. There were significant differences in age ( P=0.025), gender ( P=0.005), atrial fibrillation ( P=0.003), etiologic classification of stroke ( P=0.003), baseline NIHSS score ( P<0.001) and sICH ( P=0.003) between the poor outcome group and the good outcome group. In addition, there were significant differences in multiple blood pressure variability parameters among the above groups (all P<0.05). Multivariate logistic regression analysis showed that DBP SVdropmax, 6-12 h DBP SV, 12-18 h DBP SV, 6-12 h DBP SVdrop, 12-18 h DBP SVdrop were the independent risk factors for sICH after intravenous thrombolysis (all P<0.05); 2-6 h SBP SV, 2-6 h SBP SVrise, 2-6 h SBP SVdrop, 2-6 h DBP SV, 2-6 h DBP SVrise and 2-6 h DBP SVdrop were the independent risk factors for poor outcome after intravenous thrombolysis (all P<0.05). Conclusions:Early blood pressure and some blood pressure variability parameters are closely related to sICH and outcomes after intravenous thrombolysis in acute ischemic stroke. Closely monitoring of blood pressure and its variability can help clinical management and outcome prediction after intravenous thrombolysis.