Timing of Postoperative Stroke and Risk of Mortality After Noncardiac Surgery: A Cohort Study

Background: Postoperative stroke is a devastating complication of surgery, given its association with severe long-term disability and mortality. Previous investigators have confirmed the association of stroke with postoperative mortality. However, limited data exist regarding the relationship between the timing of stroke and survival. Addressing this knowledge gap will help clinicians develop tailored perioperative strategies to reduce the incidence, severity, and mortality associated with perioperative stroke. Therefore, our objective was to determine whether the timing of postoperative stroke influenced mortality risk. Methods: We performed a retrospective cohort study of patients > 18 years who underwent noncardiac surgery and developed postoperative stroke during the first 30 days of surgery (National Surgical Quality Improvement Program Pediatrics 2010 - 2021). Our primary outcome was 30-day mortality following the occurrence of postoperative stroke. We subdivided patients into two mutually exclusive groups: early and delayed stroke. Early stroke was defined as the occurrence within 7 days following surgery, consistent with a previous study. Results: We identified 16,750 patients who underwent noncardiac surgery and developed stroke within 30 days of surgery. Of these, 11,173 (66.7%) had an early postoperative stroke (≤ 7 days). Perioperative physiological status, operative characteristics, and preoperative comorbidities were generally comparable between patients with early and delayed postoperative stroke. Despite the comparability in these clinical characteristics, the mortality risk was 24.9% for early and 19.4% for delayed stroke. After adjusting for perioperative physiological status, operative characteristics, and preoperative comorbidities, early stroke was associated with an increased mortality risk (adjusted odds ratio: 1.39, confidence interval: 1.29 - 1.52, P-value < 0.001). In patients with an early postoperative stroke, the most common preceding complications were bleeding requiring transfusion (24.3%), followed by pneumonia (13.2%) and renal insufficiency (11.3%). Conclusions: Postoperative stroke tends to occur within 7 days following noncardiac surgery. Such timing of postoperative stroke carries a higher mortality risk, suggesting that targeted efforts to prevent stroke should focus on the first week following surgery to reduce the incidence and mortality associated with this complication. Our findings contribute to the growing understanding of stroke after noncardiac surgery and may help clinicians develop tailored perioperative neuroprotective strategies to prevent or improve treatment and outcomes of postoperative stroke.