Q. A 69-year-old woman comes for a routine follow-up visit appearing jaundiced and fatigue. She has a history of aortic valve replacement 3 years ago, and she has been using anticoagulation since then. You send her for laboratory testing, shown below. In addition, her hemoglobin level is 8.4 mg/dl. The remainder of her CBC and coagulation studies are normal: normal WBC and platelet counts and normal PT and PTT. Blood smear demonstrates schistocytes. Which of the following is the most likely diagnosis?