Objective: To evaluate the impact of early blood pressure (BP) changes on diffusion-weighted imaging (DWI) lesion evolution and clinical outcome in patients with stroke treated with IV tissue plasminogen activator (tPA).

Methods: We prospectively evaluated 80 patients with stroke with a documented middle cerebral artery occlusion treated with IV tPA. Multiple repeated systolic (SBP) and diastolic (DBP) BP measurements were obtained during 24 hours after admission. All patients underwent DWI, perfusion-weighted imaging, and magnetic resonance angiography before and 36–48 hours after thrombolysis. Recanalization was assessed on transcranial Doppler at 6 hours of stroke onset. NIH Stroke Scale scores were recorded at baseline and 24 hours. Modified Rankin Scale was used to assess 3-month outcome.

Results: Recanalization occurred in 44 (55%) patients. BP variability, estimated as the SD of the mean, was associated with DWI lesion growth (r = 0.46, p = 0.0003 for SBP and r = 0.26, p = 0.02 for DBP), early clinical course (p = 0.06 for SBP and p = 0.01 for DBP), and 3-month outcome (p = 0.002 for SBP and 0.07 for DBP). However, the prognostic significance of BP changes differed depending on the presence of recanalization. SBP variability emerged as an independent predictor of DWI lesion growth (: 6.9; 95% CI, 3.2 to 10.7, p = 0.003) and worse stroke outcome (OR: 11; 95% CI: 2.2 to 56.1; p = 0.004) in patients without recanalization, but not in recanalized patients.

Conclusion: Blood pressure variability is associated with greater diffusion-weighted imaging lesion growth and worse clinical course in patients with stroke treated with IV tissue plasminogen activator. However, its impact varies depending on the occurrence of early recanalization after thrombolysis.