Blood pressure management in acute intracerebral haemorrhage: a Time–Trajectory–Phenotype framework

Blood pressure (BP) lowering is a key component of acute intracerebral haemorrhage (ICH) care. Its clinical benefit may depend on how early an appropriate BP range is reached, how steadily it is maintained, and how well the patient tolerates the reduction. We propose a Time–Trajectory–Phenotype framework to examine these dimensions together. Our central hypothesis is that early attainment and stable maintenance of an appropriate BP range may offer greater net benefit than delayed or fluctuating control when further haematoma expansion remains preventable and BP reduction is tolerated. Time encompasses treatment initiation and target attainment. Trajectory captures reduction magnitude and rate, subsequent variability, and sustained exposure within and outside the intended range. Phenotype distinguishes baseline expansion risk from cerebral and systemic tolerance of BP reduction. Randomised trials, serial imaging, and achieved-exposure analyses provide the clinical rationale for examining these dimensions together. The first three hours provide a clinically motivated focus for investigating a therapeutic opportunity that changes over time and varies between patients. Clinically, the framework supports early, sustained guideline-based control and avoidance of excessive reduction within coordinated ICH care. BP variability and time-in-target range are proposed as candidate metrics for prospective comparisons of treatment delivery. These studies should test whether faster target attainment and more stable control improve functional outcomes and safety, and whether treatment effects vary across patient phenotypes.