Pre-Hospital Rate-Pressure Product Is Not Positively Associated with Hematoma Expansion or Initial Hematoma Volume in Spontaneous Intracranial Hemorrhage

<b>Background</b>: The management of spontaneous intracerebral hemorrhage (ICH) has centered around controlling blood pressure in order to prevent hematoma expansion (HE). Rate-pressure product (RPP) has emerged as a hemodynamic marker that accounts for heart rate (HR) and systolic blood pressure (SBP), both of which are crucial in modifying shear stress to the vasculature. We hypothesized that RPP in the pre-hospital hyperacute phase is positively associated with initial hematoma volume and HE. <b>Methods</b>: We analyzed 263 patients with primary ICH from the Field Administration of Stroke Therapy-Magnesium (FAST-MAG) study with initial and interval neuroimaging. RPP was calculated as the product of HR and SBP in pre-hospital and pre-treatment phases, stratified into quintiles. HE was defined by volume expansion of >6 mL or >33% from baseline volume on repeat neuroimaging performed within 48 h of the first scan. The primary outcome was the initial hematoma volume by quintiles of hyperacute RPP. The secondary outcome was the occurrence of HE across RPP quintiles. Multivariable logistic regression was used to assess the degree to which RPP affects HE. <b>Results</b>: Of the 263 patients analyzed, 116 (44%) had HE. The proportion of patients with HE or the initial hematoma volume was not statistically significant across RPP quintiles overall. HE was significantly more common in female patients or patients on anticoagulation. <b>Conclusions</b>: Elevated RPP was not associated with increased initial hematoma volume or subsequent HE in the hyperacute period after spontaneous ICH. Future research is necessary to determine the clinical importance of RPP as a biomarker in the clinical outcome of ICH.