Platelet Counts and Postoperative Stroke After Coronary Artery Bypass Grafting Surgery.

BACKGROUND: Declining platelet counts may reveal platelet activation and aggregation in a postoperative prothrombotic state. Therefore, we hypothesized that nadir platelet counts after on-pump coronary artery bypass grafting (CABG) surgery are associated with stroke. METHODS: We evaluated 6 130 adult CABG surgery patients. Postoperative platelet counts were evaluated as continuous and categorical (mild versus moderate to severe) predictors of stroke. Extended Cox proportional hazard regression analysis with a time-varying covariate for daily minimum postoperative platelet count assessed the association of day-to-day variations in postoperative platelet count with time to stroke. Competing risks proportional hazard regression models examined associations between day-to-day variations in postoperative platelet counts with timing of stroke (early: 0-1 days; delayed: >=2 days). RESULTS: Median (interquartile range) postoperative nadir platelet counts were 123.0 (98.0-155.0) x 109/L. The incidences of postoperative stroke were 1.09%, 1.50%, and 3.02% for platelet counts >150 x 109/L, 100 to 150 x 109/L, and 150 x 109/L. Importantly, such thrombocytopenia, defined as a time-varying covariate, was significantly associated with delayed (>=2 days after surgery; adjusted HR, 2.83; 95% CI, 1.48.5.41; P = .0017) but not early postoperative stroke. CONCLUSIONS: Our findings suggest an independent association between moderate to severe postoperative thrombocytopenia and postoperative stroke, and timing of stroke after CABG surgery. (C) 2017 International Anesthesia Research Society

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