Could blood thinners be crucial for patients with COVID-19 clots?


I will never forget my first night on call at the Duke Cardiac Care Unit (CCU). A 49-year-old woman was transferred urgently from the medical service with severe shortness of breath, hypotension and tachycardia. It was only my second month as an intern and I was pretty nervous. But I remembered enough that “Mrs. V.” was seriously ill and needed emergency medical care: central line, intravenous fluids, vasopressors, mechanical ventilation. With the confident and caring advice of my fellow cardiologist, who carefully reviewed the results of the pulmonary angiography with me, we identified the problem. Ms. V. suffered from massive pulmonary embolism (PE).

COVID-19 has been associated with the formation of clots. From deep vein thrombosis (DVT) in the lower limbs to blocked arteries in the brain and lungs, respectively causing stroke and PE, this new coronavirus is wreaking havoc on the body’s clotting system. But recent evidence suggests that blood thinners can improve the survival of patients who develop dangerous blood clots.

“COVID patients are clearly at higher risk for thrombotic events,” observes Matthew Cavender, MD, MPH, assistant professor of medicine and interventional cardiologist at University of North Carolina – Chapel Hill. Anticoagulants certainly play a role in preventing clots. Dr. Cavender adds, “There is no doubt that prophylaxis for DVT is necessary – perhaps even at slightly higher doses – and is beneficial in serious illnesses. “

What is the connection between coronavirus and clots?

The short answer is: we don’t know exactly. Researchers are still trying to understand the pathophysiology of many clinical manifestations related to COVID-19, from myocarditis to seizures. But we have some data. According to American Society of Hematology (ASH), patients with coagulopathy associated with COVID-19 express high levels of fibrinogen and d-dimer with thrombocytopenia (low platelets) – which promotes the factors of clot formation and destruction. Patients with severe COVID-19 infection may also meet the criteria for disseminated intravascular coagulopathy (DIC), a rare but serious type of abnormal blood clotting.

“Strokes, that is, macrovascular clots, and COVID toes, which are microvascular thrombi, have been described in young people,” reports Christine Cserti-Gazdewich, MD, FRCPC, clinical hematologist and specialist in transfusion medicine at University of Toronto. She adds: “PE, DVT and a” DIC “image were becoming evident in many adults, especially severe ICU cases and autopsies.”

Evidence behind blood thinners

April 30e, 2020, doctors at the Mount Sinai Health System in New York published a series of five cases in the New England Journal of Medicine young patients, all under the age of 50, infected with COVID-19 who have had large vessel strokes. Many other hospitals have reported similar results. Could anti-clot drugs be a magic bullet? Perhaps.

A recent study of 2700 patients, led by Valentin Fuster, MD, PhD, director of Mount Sinai Heart, found that blood thinners may be associated with better outcomes in hospital patients with COVID-19. Among mechanical ventilated patients receiving anticoagulation, hospital mortality was 29.1%. In contrast, mortality was more than double to 62.7% for those who were not receiving blood thinners.

“The observations of Mount Sinai are interesting,” noted Dr. Cavender. “While observation cohorts can be helpful when examining treatment effectiveness, there are likely to be fundamental differences in the severity of the disease seen in patients treated with anticoagulation during routine care and those not treated by anticoagulation. “

What does a pulmonary embolism look like? A patient’s point of view

One day, at 18, Tara Haelle began to feel short of breath. Take a few steps off the wind. “I had a cough while breathing so hard,” recalls the photojournalist and Forbes contributor colleague. “I would fall to the ground while coughing. Originally misdiagnosed as bronchitis, his symptoms progressed over the next five weeks. At first, she also experienced severe thigh pain, waking her from sleep. The pain lasted 10 minutes and then disappeared.

At the hospital, it was found that a pulmonary embolism blocked 70% of Tara’s inferior vena cava (CVI) – the main blood vessel that carries deoxygenated blood from the lower part of the body to the heart.

“The only reason he doesn’t seem to have killed me is that the clot was so big that it was actually stuck a few inches from my heart. “As for the thigh pain,” It was only years later that I realized that the pain was probably a DVT that went wild and went up to my heart. “

Ms. Haelle had a Greenfield filter placement in her IVC – “he will be there until I die” – and administered daily injections of enoxaparin (Lovenox) during both pregnancies, starting at five weeks gestation. She had also taken warfarin (Coumadin) for six months. Today, she takes aspirin daily. When asked to take so many blood thinners, she was reassured by the reduced risk of future clots. She also became aware of daily functions: “When I was in Coumadin, I avoided activities that could lead to bruises like volleyball.” She said alcohol can increase the risk of bleeding, reminding everyone that moderation is key.

Moving forward

The New York data looks promising, but we need more information. What type of blood thinner? What dose and how long? Who gets it and when?

“While New York observational data suggest that anticoagulation is associated with better coronavirus survival,” noted a cardiologist. Khadijah Breathett, MD, MS, FACC at the University of Arizona, ” a randomized trial is needed to confirm the relationship and provide strong evidence to support the use of therapeutic anticoagulation in patients infected with COVID-19. ”

Should everyone be taking aspirin? Everything in the field of medicine is a compromise. No drug is 100% benign – not even a baby aspirin. Dr. Fuster added that doctors should carefully assess the risk of bleeding for each patient.

What hematologists want to know is the amount of COVID that unmasks those who simply have innate clotting patterns versus the amount of COVID that involves inducing a change in blood behavior, “said Dr. Cserti -Gasdewich. “If we knew how to identify people at high risk, we could tailor the best possible blood thinning strategy.


In the organized chaos of the CCU, the calm and collected cardiologist gave vasopressor orders to the nurse, ventilation settings to the respiratory therapist during the patient’s intubation, and then launched the revolutionary drug – an intravenous thrombolytic agent which ruptured the clot. While explaining each step to his passionate intern – like any good leader. Over the next 24 hours, Ms. V. improved regularly. She left the CCU and eventually returned home to her family.

One of the main causes of pulmonary embolism sudden death among young people. COVID-19 complicates matters. Recognizing and managing the multisystem effects of this virus will be an ongoing challenge for the medical and research communities. We must be hypervigilant, proactive and evidence-based.If you ask any clinician, I’m sure they’ll agree, this virus is like a bat out of hell, “said Dr. Cserti-Gazdewich. “Zoonotic pun intended … and no disrespect to Meatloaf’s album. “

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