Admission rate-pressure product as an early predictor for in-hospital mortality after aneurysmal subarachnoid hemorrhage

Abstract

Early prediction of in-hospital mortality in aneurysmal subarachnoid hemorrhage (aSAH) is essential for the optimal management of these patients. Recently, a retrospective cohort observation has reported that the rate-pressure product (RPP, the product of systolic blood pressure and heart rate), an objective and easily calculated bedside index of cardiac hemodynamics, was predictively associated with in-hospital mortality following traumatic brain injury. We thus wondered whether this finding could also be generalized to aSAH patients. The current study aimed to examine the association of RPP at the time of emergency room (ER) admission with in-hospital mortality and its predictive performance among aSAH patients. We retrospectively included 515 aSAH patients who had been admitted to our ER between 2016 and 2020. Their baseline heart rate and systolic blood pressure at ER presentation were extracted for the calculation of the admission RPP. Meanwhile, we collected relevant clinical, laboratory, and neuroimaging data. Then, these data including the admission RPP were examined by univariate and multivariate analyses to identify independent predictors of hospital mortality. Eventually, continuous and ordinal variables were selected from those independent predictors, and the performance of these selected predictors was further evaluated and compared based on receiver operating characteristic (ROC) curve analyzes. We identified both low (< 10,000; adjusted odds ratio (OR) 3.49, 95% CI 1.93-6.29, p < 0.001) and high (> 15,000; adjusted OR 8.42, 95% CI 4.16-17.06, p < 0.001) RPP on ER admission to be independently associated with in-hospital mortality after aSAH. Furthermore, after centering the admission RPP by its median, the area under its ROC curve (0.761, 95% CI 0.722-0.798, p < 0.001) was found to be statistically superior to any of the other independent predictors included in the ROC analyzes (all p < 0.01). In light of the predictive superiority of the admission RPP, as well as its objectivity and easy accessibility, it is indeed a potentially more applicable predictor for in-hospital death in aSAH patients.

Keywords: Early prediction; In-hospital mortality; Intracranial aneurysm; Rate-pressure product; Subarachnoid hemorrhage; U-shaped.