Enhanced versus standard blood pressure lowering on intracranial aneurysm rupture or growth (ChATIA-1 trial): protocol for a multi-centered, prospective, open-label randomized controlled trial.

Background: Hypertension is a common comorbidity in patients with unruptured intracranial aneurysms, which is closely related to the instability of aneurysms. Though anti-hypertension therapy has been recommended by several guidelines, the optimal blood pressure range remains unknown. This trial aims to determine the optimal range of blood pressure by comparing standard blood pressure reduction and intensive blood pressure reduction to reduce the instability of unruptured intracranial aneurysms. Methods/design: This trial is a multicenter, prospective, open-label, randomized controlled trial with minimization to ensure allocation concealment. Five hundred seventy patients with unruptured intracranial aneurysms and hypertension will be recruited by nine centers in China. Patients will be allocated to the standard blood pressure lowering (SBPL) group (systolic blood pressure at 120-140 mmHg) or the enhanced blood pressure lowering (EBPL) group (systolic blood pressure at <120 mmHg). The primary outcome is aneurysm instability within 24 months after appropriate blood pressure lowering therapy, including aneurysm growth and aneurysm rupture. During follow-up, Blood pressure data will be collected monthly, while radiological examination for aneurysms will be performed at 6 ± 1 months, 12 ± 1 months and 24 ± 1 months. The trial has 85% power to reduce 60% of aneurysm instability. Discussion: The China Antihypertensive Trial for Intracranial Aneurysm (ChATIA) trial is a randomized trial about blood pressure lowering therapy for UIA patients. In this study, a new strategy and evidence will be provided for blood pressure management in the future. Clinical trial registration: http://www.clinicaltrials.gov, identifier NCT05941377.