tMCS Causing Myocardial Extramedullary Hematopoiesis Secondary to Massive Hemolysis

Abstract

In severe heart failure with hemodynamic failure, when inotropic therapies no longer suffice (INTERMACS [Interagency Registry for Mechanically Assisted Circulatory Support] 1), temporary mechanical support is used as a bridging measure until a more definitive treatment, such as a left ventricular assist device, a total artificial heart or transplantation, is performed. Due to shear stress during the passage of blood through the pump, limited hemolysis is to be expected. We describe the case of a 37-year-old patient with terminal heart failure who suffered severe hemolysis during treatment with temporary mechanical support. Examination of the cardiac apex after left ventricular assist device implantation revealed a poorly differentiated tumor. Histopathologic examination revealed underlying extramedullary hematopoiesis, triggered by severe hemolytic anemia. Following exclusion of neoplasia, the patient subsequently underwent heart transplantation. Post-transplantation, the patient was diagnosed with alpha-thalassemia and heterozygote hemoglobin E. This combination can result in mild thalassemia with chronic low-level hemolysis and mild anemia, probably severely exacerbated in the presence of high-shear stress.

Keywords: acute heart failure; blood; cardiac assist devices; cardiac transplant; complication; dysplasia; imaging; treatment.

Graphical abstract

Figure 1

Peripheral Blood Smear (A, B) Day 1 postimplantation Impella: marked anisopoikilocytosis with target cells (a), fragmentocytes, cells indicating polychromasia, and frequent normoblasts (c1), in part with dysmorphic features (c2). In addition, myeloid precursor cells with abnormal maturation (d). (C) Day 9 post heart transplantation: polychromasia and anisocytosis with target cells. No immature granulocytes and no normoblasts are present and no signs of dysplasia.

Figure 2

Trends in RBC Transfusions and Hemolysis Lab Values Trend in red blood cell (RBC) transfusions and hemolysis lab values (ie, bilirubin, haptoglobin, and free hemoglobin [Hb]). No point means no data. No haptoglobin or free hemoglobin values are available until 20 and 22 days, respectively, post admission. ECMO = extracorporeal membrane oxygenation; HTX = heart transplantation; LVAD = left ventricular assist device; PA = pulmonary arterial; VA = venoarterial.

Figure 3

Staining of Heart (A) Histology showing an overview (1×, hematoxylin and eosin stain) of the heart from epicardium (right) to endocardium (left) with granulation tissue and herein areas of high cellularity (black arrow). (B) These hypercellular regions are shown at higher magnification (40×, hematoxylin, and eosin stain), revealing a proliferation of relatively monomorphic cells reminiscent of nucleated erythroid precursors, in addition to fewer myeloid precursors. (C) Immunohistochemical staining for CD71 (40×) positively identifies these cells mainly as erythroid precursors (brown staining).

Figure 4

Diagram for Hemolysis Investigation Diagram for investigating the cause of hemolysis in a patient on temporary mechanical cardiac support (tMCS). ∗Not pathognomonic. ∗∗In case of thrombocytopenia in the context of tMCS treatment, heparin-induced thrombocytopenia must be excluded. aHUS = atypical hemolytic uremic syndrome; DIC = disseminated intravascular coagulation; EHEC = enterohemorrhagic Escherichia coli; HELLP = hemolysis, elevated liver enzymes, and low platelets; HTN = hypertonia, LDH = lactate dehydrogenase; LLN = lower limit of the norm; NEG = negative; POS = positive; TMA = thrombotic microangiopathy; TTP = thrombotic thrombocytopenic purpura; other abbreviation as in Figure 2.