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) × 10/L. The incidences of postoperative stroke were 1.09%, 1.50%, and 3.02% for platelet counts >150 × 10/L, 100 to 150 × 10/L, and <100 × 10/L, respectively. The risk for stroke increased by 12% on a given postoperative day for every 30 × 10/L decrease in platelet counts (adjusted hazard ratio [HR], 1.12; 95% confidence interval [CI], 1.01-1.24; P = .0255). On a given day, patients with moderate to severe thrombocytopenia were almost twice as likely to develop stroke (adjusted HR, 1.89; 95% CI, 1.13-3.16; P = .0155) as patients with nadir platelet counts >150 × 10/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,; 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.






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Publication Info

Karhausen, Jörn A, Alan M Smeltz, Igor Akushevich, Mary Cooter, Mihai V Podgoreanu, Mark Stafford-Smith, Susan M Martinelli, Manuel L Fontes, et al. (2017). Platelet Counts and Postoperative Stroke After Coronary Artery Bypass Grafting Surgery. Anesth Analg. 10.1213/ANE.0000000000002187 Retrieved from

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Igor Akushevich

Research Professor in the Social Science Research Institute

Mihai V. Podgoreanu

Associate Professor of Anesthesiology

1. Systems biology approaches to modeling perioperative cardiovascular injury and adaptation.
2. Mechanisms of perioperative myocardial injury; functional genomics applied to perioperative myocardial injury.
3. Metabolic consequences of perioperative myocardial ischemia-reperfusion injury.
4. Animal models and comparative genomic approaches to study perioperative myocardial ischemia-reperfusion injury.
5. Functional genomics of vein graft disease.
6. Animal models of vein graft disease.
7. Genetic association studies in perioperative medicine.
8. Clinico-genomic risk prediction models for perioperative and long-term adverse cardiovascular outcomes following cardiac surgery.

9. Intraoperative quantification of tissue perfusion by contrast echocardiography.
10. Use of myocardial tissue deformation indices to characterize perioperative ventricular dysfunction/stunning
11. 3-D echocardiographic evaluation of the right ventricle


Mark Stafford-Smith

Professor Emeritus of Anesthesiology

My research interests are in the area of Cardiothoracic Anesthesiology. The main focus of my research is towards the understanding and prevention of acute kidney injury after cardiac and other major surgeries. Secondary interests include the study of analgesic strategies after cardiothoracic surgical procedures, performance of clinical trials, and perioperative transfusion and hemostasis.

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