Non-invasive versus continuous invasive blood pressure monitoring during endovascular treatment of acute ischemic stroke under general anesthesia - a pilot study.

Abstract

Aim of the study: To assess the agreement between continuous invasive (IBP) and intermittent non-invasive blood pressure (NIBP) monitoring during endovascular treatment (EVT) of acute ischemic stroke (AIS) under general anesthesia, and to evaluate the frequency of clinically relevant discrepancies between both methods and the potential impact of IBP use on treatment initiation times.

Clinical rationale for the study: Intraprocedural hypotension during mechanical thrombectomy (MT) is associated with worse outcomes in AIS patients. While continuous IBP monitoring is frequently used during procedures with high-risk of hypotension, it is not universally adopted in stroke EVT. Accurate, real-time hemodynamic monitoring may be essential to guide timely therapeutic interventions and optimize outcomes.

Materials and methods: In this prospective observational study, 30 AIS patients undergoing MT under general anesthesia were included. Simultaneous IBP and NIBP measurements were recorded throughout the procedure. Non-invasive blood pressure was measured every 5 minutes on one arm, while IBP was continuously recorded from a radial arterial catheter in the contralateral upper extremity. Paired readings were analyzed using Bland-Altman plots. The proportion of time with clinically relevant discrepancies between measurements was calculated. Additionally, door-to-groin (DTG) times were compared between patients with and without intended IBP monitoring.

Results: A total of 481 paired IBP and NIBP readings were analyzed. While mean differences for systolic blood pressure (SBP) and mean arterial pressure (MAP) were small (-0.64 mm Hg and -0.99 mm Hg, respectively), limits of agreement were wide (SBP: -40.6 to 39.4 mm Hg; MAP: -28.5 to 26.5 mm Hg). Diastolic blood pressure (DBP) showed poor agreement with a mean bias of -7.64 mm Hg. Discrepancies of ≥ 20 mm Hg for SBP occurred in 41.0% (IQR = 28.0-59.4%) of the procedure time, and discrepancies > 15 mm Hg for MAP in 29.6% (IQR = 22.8-58.5%). DTG times did not differ significantly between the IBP and NIBP groups (median: 41 vs. 38 minutes, p = 0.217).

Conclusions and clinical implications: Non-invasive blood pressure may show limited agreement with IBP and miss clinically relevant hemodynamic changes due to its intermittent nature and overestimation of blood pressure during hypotensive episodes. Invasive monitoring does not appear to delay treatment initiation and may improve blood pressure control in AIS patients undergoing EVT under general anesthesia. These findings, from a pilot study, should be interpreted with caution but provide a basis for larger prospective investigations.