Major adverse cardiovascular events (MACE) are leading causes of perioperative morbidity and mortality following major noncardiac surgery. Intraoperative arterial hypotension is strongly associated with postoperative morbidity and mortality. However, interventional trials have been unable to demonstrate clinically relevant reductions in the incidence of postoperative MACE, which can potentially be explained by the hitherto lacking consideration of patient-specific autoregulatory boundaries. This is especially problematic considering that the presumed mechanism of hypotension-induced organ injury is hypoperfusion due to transgression of the lower limit of blood flow autoregulation. In other clinical settings, excursions below the autoregulatory threshold have been shown to be superior predictors of adverse events than excursions below absolute blood pressure (BP) thresholds, however, there is a paucity of data in major noncardiac surgery.~This prospective, multicenter cohort observation study is to investigate the clinical relevance of blood pressure excursions below autoregulatory boundaries in major noncardiac surgery.~This project will consist of a Main study in which all patients will be enrolled and of a Neurologic injury substudy in which select patients will be enrolled.
This study is to investigate the clinical relevance of blood pressure excursions below autoregulatory boundaries in major noncardiac surgery. The study investigates a precedent for a personalized definition of intraoperative arterial hypotension based on non-invasive tissue oxygenation measurements. The feasibility of NIRSbased autoregulation monitoring in major noncardiac surgery and the prognostic relevance of excursions below the NIRS-derived lower limit of autoregulation (LLA) with regard to both short- and long-term major adverse cardiovascular events (MACE) will be analyzed.~This project will consist of a Main study in which all patients will be enrolled and of a Neurologic injury substudy in which select patients will be enrolled.