pulmonary atresia, (2) associated with systemic obstruction-aortic arch interruption, and (3) with unrestricted systemic and pulmonary flows. PFAA might be asymptomatic when it forms a subclavian artery arising from the ascending aorta (type A3) 3 or a double-lumen (subway) type of aortic arch in the absence of aortic interruption or coarctation (type A1). 1 No intervention is needed in such patients. At the other end of the spectrum, it might be an isolated anomaly connecting the ascending aorta to the PA, leading to increased pulmonary blood flow and heart failure (type B3). 4 PFAA can have a beneficial hemodynamic role in both systemic-systemic and systemic-pulmonary configurations. It serves as a conduit for systemic blood flow when associated with aortic atresia, aortic arch interruption, or aortic coarctation 1 and pulmonary blood flow when associated with pulmonary atresia. 5 The varied clinical presentation of this entity leads to misdiagnosis and under-estimation of the true incidence of PFAA. Gerlis and colleagues 1 report an incidence of 1 in 330 autopsy cases in an analysis of 2000 pathologic specimens. Familiarity with the different clinical presentations will aid in avoiding misdiagnosis of this entity.From the Division of Cardiac and Vascular Surgery a and Transfusion Medicine and Tissue Bank,

BACKGROUND Evans syndrome is a rare autoimmune disorder that is defined by the simultaneous or sequential presence of two or more cytopenias without an obvious underlying precipitating cause. Evans syndrome usually follows a chronic relapsing and remitting course and is quite rare, making it difficult to evaluate in clinical studies. CASE REPORT A 66‐year‐old male patient with a 17‐year history of Evans syndrome presented with fulminant autoimmune hemolytic anemia (AIHA). He presented with a markedly elevated C‐reactive protein (CRP; 46 mg/L [normal, 0‐5 mg/L]) before onset of a decrease in hemoglobin. He required the transfusion of 20 units of red blood cells while awaiting response to aggressive immunosuppressive therapy including high‐dose corticosteroids, intravenous immunoglobin therapy, and rituximab. He achieved a complete hematologic response. RESULTS His postdischarge course was complicated by acute cholecystitis requiring laparoscopic cholecystectomy. In addition, his transfusional iron overload requiring 16 phlebotomies to reduce his ferritin level from 4933 μg/L to 326 μg/L, with phlebotomies ongoing every 2 weeks to achieve a ferritin level of less than 100 μg/L. CONCLUSION Neither transfusional iron overload nor acute cholecystitis are well‐recognized complications of a severe episode of AIHA. An elevated CRP has been recently recognized as an important prognostic marker in patients with immune thrombocytopenic purpura and this case suggests a need to evaluate its utility in AIHA.

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Objectives: To report a rare case of acute hemolytic transfusion reaction (AHTR) following an ABO plasma incompatible group B platelet transfusion.Background: AHTR is an uncommon, but potentially fatal event. Most reported cases of platelet transfusions associated with AHTR involve group O donors.Case Report: A 34-year-old man, recipient of a group AB haploidentical haematopoietic stem cell transplantation (HSCT), had received re-induction chemotherapy for leukaemia relapse. A group B whole blood-derived buffy coat platelet pool was transfused. He developed rigours/fever, profound hemolytic anaemia, and hemodynamic instability. Serological investigations revealed AHTR from passive transfer of high titre anti-A (256 for IgM and 8192 for IgG).Discussion: This case highlights the potential risks associated with ABO-mismatched transfusions, and the complexity associated with transfusing HSCT recipients and red cell transfusion recipients with dual populations of circulating red cells. The literature on minor ABO plasma incompatible transfusions, challenges in establishing local policies to limit the risks of AHTR and risk mitigation strategies are discussed. Conclusion:Clinicians must maintain a high level of suspicion for AHTR after ABO plasma incompatible platelet transfusions. Patients must be aware of the risks of AHTR, and early recognition and diagnosis of this complication may be lifesaving.