Autoregulation-based Blood Pressure Optimization After Large-vessel Ischemic Stroke using Non-invasive Near-infrared Spectroscopy Monitoring (S21.008)

Abstract

Objective: To determine the effect of individualized, autoregulation-based blood pressure (BP) targets on functional outcome among stroke patients undergoing endovascular therapy. Background(s): Abnormalities in cerebrovascular autoregulation in the acute phase of large-vessel occlusion (LVO) stroke increase the risk of secondary brain injury from relative cerebral hypo- or hyperperfusion. While BP is an important modifiable target to ensure proper cerebral perfusion, how to best manage BP during the early stages of LVO stroke remains uncertain. Autoregulation-derived, personalized BP management is a plausible strategy that would provide the optimal physiologic environment for the injured brain. Design/Methods: We prospectively enrolled 21 patients with LVO stroke admitted to the Neuro ICU at Yale-New Haven Hospital. Autoregulatory function was continuously measured by interrogating changes in the near-infrared spectroscopy (NIRS)-derived tissueoxygenation index - a surrogate of cerebral blood flow - and arterial BP using time-correlation analysis. MAPopt was defined as the BP where autoregulation was best preserved or "optimal". DELTAMAPopt was calculated as the absolute difference between mean MAP and MAPopt in individual patients. Functional outcome was assessed using the modified Rankin Scale (mRS) at discharge and 90 days. Associations between DELTAMAPopt and outcome were assessed using ordinal regression. Result(s): Identification of MAPopt was possible in all patients (mean age 70+/-16, 6F, mean NIHSS 16) with an average monitoring time of 19.4+/-7 hours. Average MAP was 89+/-11.2 mmHg and the mean DELTAMAPopt was 9.3+/-7.9 mmHg. DELTAMAPopt was significantly associated with mRS at discharge (p=0.0137), and at 90 days (p=0.0278). Every 5 mmHg deviation from MAPopt was associated with a 3.2-fold likelihood of shifting towards a worse outcome on the mRS at 90 days. Conclusion(s): Increased deviation from optimal MAP targets is associated with worse functional outcome. Our study suggests that autoregulation-based BP management using non-invasive NIRS monitoring is feasible and could guide the therapeutic course of LVO stroke to optimize clinical outcomes.