Intraoperative Blood Pressure Variability and Early Postoperative Stroke: A Case-Control Study

BACKGROUND: This study aims to assess the association of postoperative stroke with intraoperative hemodynamic variability and transfusion management. METHODS: In this case-control study, adult patients (≥ 18 years) who had a stroke within 72 hours of a surgical procedure were matched to 2 control patients according to age, sex, and procedure type. Primary risk factors assessed were intraoperative fluid administration, blood product transfusion, vasopressor use, and measures of variability in systolic and diastolic blood pressure and heart rate: maximum, minimum, range, SD, and average real variability. The variables were analyzed with conditional logistic regression, which accounted for the 1:2 matched case-control study design. RESULTS: Among 687 581 procedures, we identified 64 postoperative strokes (incidence, 9.3 [95% CI, 7.2-11.9] strokes per 100 000 procedures). These cases were matched with 128 controls. Stroke cases had higher Charlson cmorbidity index scores than did controls (P = .046). Blood pressure and heart rate variability measures were not associated with stroke. The risk of stroke was increased with red blood cell (RBC) transfusion (odds ratio [OR], 14.82; 95% CI, 3.40-64.66; P < .001), vasopressor use (OR, 3.91; 95% CI, 1.59-9.60; P = .003), and longer procedure duration (OR, 1.23/h; 95% CI, 1.01-1.51; P = .04). Multivariable analysis of procedure duration, RBC transfusion, and vasopressor use showed that only RBC transfusion was independently associated with an increased risk of stroke (OR, 10.10; 95% CI, 2.14-47.72; P = .004). CONCLUSIONS: Blood pressure variability was not associated with an increased risk of postoperative stroke; however, RBC transfusion was an independent risk factor.