Association of Personalized Blood Pressure Targets With Hemorrhagic Transformation and Functional Outcome After Endovascular Stroke Therapy

Abstract

This cohort study assesses the feasibility of determining personalized blood pressure targets as well as the association of deviating from these targets with radiographic and clinical outcomes.

Figure 1.. Calculating Optimal Blood Pressure and Limits of Autoregulation

A, A 48-hour continuous recording of mean arterial pressure (MAP) and near-infrared spectroscopy–derived tissue oxygenation index (TOI) in a patient with large-vessel occlusion ischemic stroke. The second trend shows a time series of the tissue oxygenation autoregulatory index (TOx), calculated as a rolling Pearson correlation coefficient between 30 successive, time-averaged values of MAP and TOI. B, The limits of autoregulation were calculated by dividing MAP values into groups of 5 mm Hg and plotting them against corresponding TOx indices over a 4-hour monitoring period, resulting in a characteristic U-shaped curve on ICM+ software (University of Cambridge). By superimposing a threshold for impaired autoregulation (TOx = 0.30), the intersecting MAP values provide estimates of the lower and upper limits of autoregulation (LLA and ULA, respectively). The vertex of the curve corresponds to the MAP with the most preserved autoregulation (ie, MAP_OPT). The orange shaded area indicates optimal cerebral blood flow (CBF). C, A continuous time trend of optimal MAP (orange line), ULA, and LLA (red lines surrounding MAP_OPT) can be calculated in this manner, while superimposing the patient’s blood pressure (black line) in real time. This trend provides clinicians with a dynamically updating, visual MAP target. The gray shaded areas (vertical panels) highlight times the patient’s blood pressure deviated from personalized limits of autoregulation.

Figure 2.. Associations of Individualized Limits of Autoregulation With Functional Outcome and Hemorrhagic Transformation

A and B, The percentage of time spent above the upper limit of autoregulation (ULA) (% time > ULA) was plotted per each modified Rankin scale (mRS) score at discharge and 90 days. C, The percentage of time above the ULA is shown among degrees of hemorrhagic transformation (HT) and symptomatic intracerebral hemorrhage (sICH). The open circles represent the patient’s percentage of time outside LA outside the 95% confidence interval. HI indicates hemorrhagic infarction; MAP, mean arterial pressure; PH, parenchymal hematoma. ^aIndicates significant differences.