From the Guidelines
The workup for Impella-driven hemolysis should begin with a thorough history and physical examination, followed by laboratory tests including CBC with peripheral smear, LDH, haptoglobin, bilirubin, reticulocyte count, and free hemoglobin, as recommended by the most recent guidelines 1. The initial evaluation should focus on identifying signs of hemolysis, such as anemia, macrocytosis, and evidence of hemolysis on peripheral smear.
- Key laboratory tests include:
- CBC with peripheral smear to assess for anemia and evidence of hemolysis
- LDH, haptoglobin, bilirubin, reticulocyte count, and free hemoglobin to confirm hemolysis and assess its severity
- DIC panel, which could include PT or INR or PTT, to evaluate for coagulopathy
- Autoimmune serology and PNH screening to rule out underlying autoimmune or hematologic disorders
- Additional tests may be necessary to evaluate for other causes of hemolysis, such as:
- Direct and indirect bilirubin, direct agglutinin test, and bone marrow analysis to evaluate for MDS or other bone marrow disorders
- Evaluation for viral or bacterial causes of hemolysis, including mycoplasma and other infectious agents
- Protein electrophoresis and cryoglobulin analysis to evaluate for paraproteins or cryoglobulins
- It is also essential to assess for common drug causes of hemolysis, including ribavirin, rifampin, dapsone, interferon, cephalosporins, penicillins, NSAIDs, quinine or quinidine, fludarabine, ciprofloxacin, lorazepam, and diclofenac, as well as to evaluate for glucose-6-phosphate dehydrogenase deficiency 1. Device-specific evaluations should include checking for proper positioning using imaging (echocardiography or fluoroscopy), assessing for suction events, and reviewing pump parameters including motor current and purge system function, to optimize device function and minimize the risk of hemolysis 1.
From the Research
Workup for Impella Driven Hemolysis
- Impella driven hemolysis is a complication that can occur due to improper placement of the Impella device, and it is essential to use imaging modalities like ultrasound to guide proper placement 2.
- Hemolysis in patients supported with Impella 5.5 is associated with higher admission SCAI stages, more Impella 5.5 days, more additional mechanical circulatory support, and more transfusions of packed red blood cells, fresh frozen plasma, and platelets 3.
- The incidence of hemolysis in patients with cardiogenic shock treated with Impella percutaneous left ventricular assist device is high, with a cumulative incidence of 62.5% 4.
- Hemolysis is a clinical entity that can be severe and is commonly of multifactorial etiology, and immunohematological work-up must be very rigorous to ensure transfusion management with utmost safety 5.
- In the context of mechanical hemolysis, very high lactate dehydrogenase (LDH) levels and a low reticulocyte count are strongly suggestive of pseudothrombotic microangiopathy related to vitamin B12 deficiency, and vitamin supplementation can lead to hematological improvements 6.
Diagnostic Factors
- Plasma free hemoglobin (PfHb) levels can be used to categorize patients into high hemolysis (HH) and low hemolysis (LH) groups 3.
- Lactate dehydrogenase (LDH) levels, bilirubin levels, and haptoglobin levels can be used to evaluate hemolysis in patients supported with Impella 4.
- Reticulocyte count and neutrophil count can be used to distinguish between thrombotic thrombocytopenic purpura (TTP) and pseudothrombotic microangiopathies related to vitamin B12 deficiency 6.
Management
- Strict monitoring of hemolysis parameters at baseline and at frequent intervals is crucial in patients supported with Impella 4.
- Transfusion management with utmost safety is essential in patients with hemolysis, and immunohematological work-up must be very rigorous 5.
- Vitamin supplementation can lead to hematological improvements in patients with pseudothrombotic microangiopathy related to vitamin B12 deficiency 6.