What is the next step for a 73-year-old man with a history of COVID-19 (Coronavirus Disease 2019) who develops a deep vein thrombosis (DVT) of the left lower extremity despite anticoagulation with Low Molecular Weight Heparin (LMWH) and has thrombocytopenia (platelet count of 60,000)?

From the Guidelines

The next step for this 73-year-old man with a new DVT despite LMWH prophylaxis, recent COVID-19 infection, and thrombocytopenia (platelet count 60,000) is to suspect and test for heparin-induced thrombocytopenia (HIT) and immediately discontinue all heparin products, including LMWH. This decision is based on the high risk of thrombotic complications in patients with COVID-19, as well as the potential for heparin-induced thrombocytopenia, as suggested by the American Society of Hematology living guidelines on the use of anticoagulation for thromboprophylaxis in patients with COVID-19 1. The patient should be started on a non-heparin anticoagulant such as argatroban (initial dose 0.5-1.2 mcg/kg/min IV, adjusted to target aPTT 1.5-3 times baseline) or fondaparinux (7.5 mg subcutaneously daily for patients weighing 50-100 kg), as recommended by the guidelines for patients with suspected HIT 1. Some key points to consider in the management of this patient include:

• The high incidence of thrombotic complications in critically ill patients with COVID-19, with VTE being the most common thrombotic complication, as reported in up to 23% of critically ill patients with COVID-19 1
• The potential for bleeding complications in critically ill patients, which may also occur in patients with COVID-19–related critical illness, and the need to balance thrombosis and bleeding risks 1
• The recommendation to use standard dose anticoagulant thromboprophylaxis over intermediate or full treatment dosing, per existing guidelines, in acutely ill hospitalized patients with COVID-19, as suggested by the Chest guideline and expert panel report 1
• The importance of monitoring the patient's clinical status and risk factors to guide the selection and duration of therapeutic anticoagulation for the new DVT. Given the recent COVID-19 infection and the development of DVT despite LMWH prophylaxis, it is essential to prioritize the patient's morbidity, mortality, and quality of life, and to make decisions based on the most recent and highest quality evidence available 1.

From the FDA Drug Label

If the platelet count falls below 100,000/mm3 or if recurrent thrombosis develops, promptly discontinue heparin, evaluate for HIT and HITT, and, if necessary, administer an alternative anticoagulant. Thrombocytopenia in patients receiving heparin has been reported at frequencies up to 30%. It can occur 2 to 20 days (average 5 to 9) following the onset of heparin therapy. Obtain platelet counts before and periodically during heparin therapy. Monitor thrombocytopenia of any degree closely

The patient's platelet count is 60,000, which is below the threshold of 100,000/mm3. The next step is to:

• Discontinue heparin
• Evaluate for HIT and HITT
• Administer an alternative anticoagulant if necessary 2

From the Research

Patient Assessment

• The patient is a 73-year-old man with a history of Covid-19 one month prior, currently hospitalized with a deep vein thrombosis (DVT) of the left lower extremity despite using low molecular weight heparin (LMWH).
• The patient's platelet count is 60,000, indicating thrombocytopenia.
• The patient's condition suggests a possible diagnosis of heparin-induced thrombocytopenia (HIT), which is a complication of heparin therapy characterized by thrombocytopenia and paradoxical thrombosis 3.

Diagnostic Considerations

• The "4 Ts" criteria can be used to support a diagnosis of HIT: thrombocytopenia, timing of platelet count fall, thrombosis or other complications, and other causes for thrombocytopenia 3.
• An HIT antibody test can be used to confirm the diagnosis of HIT 3.
• Other causes of thrombocytopenia, such as immune thrombocytopenia or drug-induced thrombocytopenia, should be considered and ruled out 4.

Treatment Options

• If HIT is suspected, all heparin products should be discontinued immediately 3.
• Alternative anticoagulants, such as lepirudin, argatroban, bivalirudin, or fondaparinux, can be used to treat HIT 3.
• The choice of anticoagulant and dosing should be individualized based on the patient's condition and the presence of liver or renal failure 3.
• Platelet transfusions may be considered if the patient has a low platelet count and is at risk of bleeding 4.

Management of Thrombocytopenia

• Patients with thrombocytopenia should be managed carefully to minimize the risk of bleeding and thrombosis 4, 5.
• The use of anticoagulants in patients with thrombocytopenia should be carefully considered, as it may increase the risk of bleeding 5, 6.
• However, some studies suggest that anticoagulants can be safely used in patients with thrombocytopenia without increasing the risk of bleeding 5.