Assessing Bleeding Risk in Pediatric Patients Undergoing Major Spinal Surgery

Preoperative screening for bleeding disorders in pediatric patients is problematic due to children's limited exposures to significant hemostatic challenges and the inherent difficulty in obtaining blood samples from young patients. Overcoming these challenges is of particular importance for surgical procedures that carry a significant bleeding risk, such as spinal surgeries. Many pediatric surgeons, including the Pediatric Orthopedic team at our Institution, rely on an unfocused history and measurement of general markers of hemostasis for preoperative screening. In order to improve preoperative screening of pediatric patients undergoing spinal procedures, we instituted the use of a detailed semi-quantitative questionnaire based on the ISTH Bleeding Assessment Tool (BAT), in combination with evaluation of PT, aPTT, platelet count, and PFA. The BAT gives positive points for a personal or family history of bleeding, and negative points for significant hemostatic challenges that did not result in bleeding complications. It was decided a priori that a BAT score of ≥3 would result in referral to Pediatric Hematology. A total of 212 patients presenting for major spinal surgeries (e.g., spinal fusion, growth rod placement) ranging in age from 3 to 25 years were prospectively evaluated in this fashion. A total of 41 patients (19.3%) had a prolongation of the PT and/or aPTT, none of which had a high BAT score. The majority of the abnormal PT/aPTT values were minimal prolongations that were not reproducible on repeat testing. Prolongation of the PT and/or aPTT revealed 3 patients with mild deficiencies of either factors VII, X, or XI, none of which were felt to be clinically significant. Prolonged PFAs were observed in 32 patients (16%), 1 of which was diagnosed with type I VWD (BAT score = 1), and the other with "possible VWD" based on a borderline VWF antigen level (BAT score = 0). Both were treated with Humate P. The remainder of the patients with a prolonged PFA were determined not to have a significant bleeding disorder after further testing. A total of 15 patients were referred to Hematology based on a high BAT score. Of these, 2 had a history of thrombocytopenia (1 with known DiGeorge syndrome and 1 with Depakote-related thrombocytopenia). Neither required platelet transfusion. One patient with a high BAT score was known to have type I VWD and was treated with Humate P, another was diagnosed with low expression of glycoprotein GP1b and was treated with Humate P and platelet transfusion. The remainder of the patients with high BAT scores were not felt to have a clinically significant bleeding disorder based on a Hematologist's assessment. None of the 212 patients evaluated were felt to have excessive intraoperative bleeding by the surgical team, suggesting that none of the patients had a significant undiagnosed hemostatic defect. Together, these results suggest that reliance on history or screening labs alone may not be sufficient for many pediatric surgery patients. While the PFA identified 2 patients with mild/possible VWD that would have been missed by the BAT, the PFA also had a significant number of apparent false positives. The combination of a BAT and a platelet count, as well as assessment of VWF activity for patients without previous hemostatic system challenges, may provide a more effective screening methodology for institutions with ready access to VWF activity measurement.