Is cerebrovascular autoregulation associated with outcomes after major noncardiac surgery? A prospective observational pilot study

Background Studies have identified multiple risk factors for development of cognitive decline after surgery. Impaired cerebrovascular autoregulation may be a contributor to postoperative cognitive decline. Methods One hundred and forty patients admitted for major elective noncardiac surgery were recruited. Near-infrared spectroscopy was used to calculate the tissue oxygenation index of dynamic autoregulation (TOx). The primary endpoint was Day 3 cognitive recovery as assessed using the Postoperative Quality of Recovery Scale. The secondary endpoint was a combined major adverse event of death, acute myocardial infarction, cardiac arrest, stroke, pulmonary embolism, sepsis, and acute kidney injury at Day 30. Results Higher optimal TOx values, signifying impaired autoregulation, were associated with worse outcomes. Patients who cognitively recovered at Day 3 (n = 47) had lower optimal TOx values (TOx(opt)) than patients who did not recover (n = 22): 0.06 (0.24) vs 0.18 (0.16) (mean [SD]), P = 0.02. Patients who did not suffer a major adverse event (n = 102) had lower TOx(opt) than patients who did (n = 17): 0.09 (0.21) vs 0.20 (0.27), P = 0.04. When dichotomized as having impaired or intact autoregulation based on TOx(opt) levels, a value of TOx(opt) >= 0.1 correctly identified 72.7% of patients who did not cognitively recover, OR 3.3 (1.1-9.9) (Odds ratio, [95% CI]), P = 0.03. TOx(opt) >= 0.1 correctly identified 82.4% of patients who suffered a major adverse event, OR 4.7 (1.3-17.2), P = 0.02. Conclusions In older and higher risk patients having major noncardiac surgery, impaired cerebrovascular autoregulation was associated with failure of cognitive recovery in the early postoperative period and with 1-month mortality and morbidity.