Loyola University Medical Center, Illinois, United States
Background/Case Studies: Vel is a high prevalence red blood cell (RBC) antigen, with a Vel-negative RBC phenotype occurring in approximately 1 in 4000 individuals. Vel-negative alloimmunized patients predictably require products from the American Rare Donor Program (ARDP) for transfusion support. A 45-year-old female presented with severe aortic stenosis and an ascending aortic aneurysm, requiring aortic valve replacement (AVR) and aneurysm repair. Routine pre-transfusion investigation into the patient’s medical records revealed a historical anti-Vel antibody that was previously identified at a separate institution in 2008. Following the identification of this antibody, subsequent testing revealed that the patient’s sister was also Vel-negative, and both siblings have donated multiple units to the ARDP.
Study
Design/Methods: To prepare for elective cardiothoracic (CT) surgery, a multidisciplinary team collaborated to optimize blood procurement and conservation techniques. Following a discussion with CT surgery, 4 RBC units were requested to address anticipated transfusion needs. These units would be supplemented by blood conservation techniques including intraoperative blood salvage (Cell Saver) and acute normovolemic hemodilution. One liquid RBC unit and three deglycerolized Vel-negative RBC units were available to the Transfusion Service for surgery based on regional blood center inventory. All units were irradiated (donor identities unknown) and compatible on crossmatch at AHG phase. As a contingency, two liquid Vel-negative RBC units from the ARDP were additionally available. After anesthesia induction, one unit of whole blood with ANH was planned.
Results/Findings: Baseline preoperative H&H was 13.2g/dL / 40.7%. Intraoperatively, the H&H nadir was 5.4g/dL / 16.0% and the patient received 2 washed RBC’s, one unit of apheresis platelets, and one pooled cryoprecipitate. The patient was additionally supported with the ANH RBC unit, 225mL of Cell Saver RBC's while on-pump, and post-bypass return of 350mL RBC’s. H&H was 9.6g/dL / 27.6% at surgery end, and 11.9g/dL / 39% on POD #1. No post-op bleeding occurred, but the course was complicated by progressive AKI (creatinine peak 9.7mg/dL). On POD #5 the H&H dropped to 7.8g/dL / 22.3%, requiring transfusion of one Vel-negative liquid RBC. The AKI slowly resolved and the H&H stabilized at 9.6g/dL / 27.9%, with subsequent discharge on POD #13. Conclusions: CT surgery was successfully performed on a Vel alloimmunized patient following the collaborative efforts of a multidisciplinary team including Transfusion Medicine as well as colleagues from the regional Blood Center, CT surgery, Anesthesiology, and OR Perfusion. A combination of blood conservation techniques and coordinated procurement of rare crossmatch compatible units allowed for appropriate transfusion support both during and after surgery.
