Intraoperative Hypotension and Perioperative Stroke Risk in Unruptured Intracranial Aneurysm Surgery

Introduction: Emerging research has linked intraoperative hypotension to an elevated risk of perioperative stroke, especially in neurosurgical contexts. Yet, a specific blood pressure threshold for unruptured intracranial aneurysm (UIA) surgery remains undefined. This study investigates this threshold and its correlation with stroke risk.

Methods: The CAIASA study (Coexistence of Atherosclerotic Intracranial Arterial Stenosis With Intracranial Aneurysms) served as the basis for our prospective inclusion of UIA patients treated at Beijing Tiantan Hospital from October 2015 to December 2020. We measured intraoperative blood pressure directly or indirectly and defined perioperative stroke as symptomatic or asymptomatic cerebral ischemic events during hospitalization. We used restricted cubic splines to assess potential nonlinear relationships between lowest sustained blood pressure and stroke, followed by segmented logistic regression to adjust for confounders and analyze associations.

Results: Among 2441 patients included in this study, 246 (10.1%) suffered perioperative strokes. We identified a significant nonlinear relationship between the lowest sustained blood pressure and stroke risk (p=0.001), with an inflection point at 68 mmHg. Blood pressure below this point was inversely associated with stroke risk (OR= 0.83, 95% CI [0.71-0.99]).

Conclusion : We propose 68mmHg as the intraoperative hypotension threshold for UIA surgery, below which there is a significant association with increased perioperative stroke risk.