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OBJECTIVES:
Preoperative testing for carotid endarterectomy (CEA) often includes blood typing and antibody screen (T&S). In our institutional experience, however, transfusion for CEA is rare. We assessed transfusion rate and risk factors in a national clinical database to identify a cohort of patients in whom T&S can be avoided with the potential for substantial cost savings.
METHODS:
Using the NSQIP database, transfusion events and timing were established for all elective CEAs in 2012. Comorbidities and other characteristics were compared for patients receiving intra- or postoperative transfusion and those that did not using two-tailed t-test or Fisher’s exact test. Using one half of the data set, a point-based risk prediction model that was then validated on the other half.
RESULTS:
Of 7601 patients undergoing CEA in 2012, 139 received at least one transfusion prior to discharge (1.8%). 80% of transfusions occurred on POD#0 or #1. Hematocrit 1.2 [OR: 3.0; 95%CI: 1.7-5.1], female sex [OR: 1.8; 95%CI: 1.1-3.1] and preoperative open wound [OR: 5.0; 95%CI: 1.6-16.3] among other risk factors predicted transfusion.
Score was calculated with 1 point for female gender, preoperative dyspnea, preoperative coagulopathy and BMI 1.2 and 8 points for hematocrit <30. A risk prediction model based on these data produced a C-statistic of 0.84. Application of this model to the validation set demonstrated a C-statistic of 0.76. 77% of patients in the validation set received a score of 2 or less corresponding to a transfusion risk of 1.1%. Omitting a T&S in these patients would generate a potential annual cost-saving to NSQIP hospitals of over ,000,000 based on our institutional charge.
CONCLUSIONS:
While T&S is commonly performed for patients undergoing CEA, transfusion following CEA is rare and well predicted by a transfusion risk score. Avoidance of T&S in this low-risk population provides a substantial cost-saving opportunity without compromise of patient care.