Case Presentation: A 53-year-old woman with a history of bioprosthetic aortic valve (AV) placement in 2014 presented with three weeks of exertional dyspnea and dark stools. On presentation stool guaiac was positive and her hemoglobin was 5.1 g/dl. She was transfused four units of blood and underwent EGD showing gastric and duodenal angiodysplasias (AD) but no active bleeding and an unremarkable colonoscopy. However, the patient’s hemoglobin remained below 7 g/dL despite repeated transfusions. Hemolysis studies were sent and significant for LDH of 434 U/L and haptoglobin < 30 mg/dl. The results of a von Willebrand’s factor (vWF) gel electrophoresis showed decreased high molecular weight multimers of vWF suggestive of von Willebrand disease (vWD). An echocardiogram showed a high AV gradient with moderate regurgitation and the patient underwent valve revision. On outpatient follow up one month after discharge, the patient’s hemoglobin was stable at 11 g/dL with no evidence of hemolysis or gastrointestinal bleed.
Discussion: There are three mechanisms by which anemia can arise; decreased red blood cell production (RBC), increased RBC destruction, and hemorrhage. In a patient with native or prosthetic valve aortic stenosis (AS), the increased transvalvular velocity of blood causes increased shear stress on RBCs, leading to intravascular hemolysis. While hemolysis is very common in patients with newer generation prosthetic valves (51.2%), hemolysis severe enough to cause anemia is rare (< 1% of patients) and typically associated with regurgitation around the valve. Manifestations in these patients may include symptoms of heart failure and elevated LDH. Iron and folate are usually sufficient to treat these patients but valve revision may be required if valve failure or regurgitation is present. AS may also contribute to anemia through bleeding from gastrointestinal angiodysplasias. The link is vWD, a bleeding diathesis that develops in AS and results from a deficiency in the quality or quantity of vWF in the blood. The triad of AS, acquired vWD, and AD is termed Heyde’s syndrome (HS). In HS, a narrowed AV opening and increased blood flow velocity contribute to increased shear stress on vWF multimers. This results in increased proteolysis of multimers by ADAMTS13. Proteolysis of vWF multimers results in an acquired vWD bleeding diathesis. It is also thought that decreased vWF levels may allow angiogenesis to occur at higher rates, increasing the likelihood of AD formation. The definitive diagnosis of HS in a patient with AS is made by vWF gel electrophoresis showing the absence of large vWF multimers. The mainstay of treatment is valve revision.
Conclusions: In patients with AS, there are two potential etiologies of anemia: hemolysis and GI bleeding due to the acquired vWD of Heyde’s syndrome.
To cite this abstract:Ventimiglia, AV; Kolod, E; Shaines, M. THE SHEAR STRESS OF IT ALL. Abstract published at Hospital Medicine 2019, March 24-27, National Harbor, Md. Abstract 1058. https://www.shmabstracts.com/abstract/the-shear-stress-of-it-all/. Accessed February 24, 2020.