Hemoglobinuric acute kidney injury in a patient with a kinked prosthetic aortic graft .

Acute kidney injury (AKI) due to intravascular hemolysis has been well described in paroxysmal nocturnal hemoglobinuria (PNH) and in cardiac valvular dysfunction. However, reported cases of hemoglobinuric AKI from prosthetic aortic grafts are sparse. We present a case of microangiopathic hemolytic anemia and hemoglobinuric AKI presenting 9 days after repair of an ascending aortic dissection with a prosthetic graft. After an unremarkable recovery following the initial procedure, the patient presented on postoperative day 9 with dyspnea, fatigue, and cola-colored urine. Attempts to manage conservatively with intravenous fluids, blood pressure control, and erythrocyte transfusion were unsuccessful. A magnetic resonance angiography revealed narrowing of the ascending aorta with a kink, causing turbulent blood flow. Surgical intervention was indicated due to persistent hemolysis, transfusion-refractory anemia, and worsening renal function. After surgical release of the kinked graft, his AKI and hemolysis labs improved immediately. On follow-up, his anemia resolved, and renal function returned to baseline, although he continues to have subclinical hemolysis.
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