Cardiovascular Links to COVID-19 and Exploring Treatments with Anti-Coagulants

COVID-19 comes with many possible complications for patients, including cardiovascular ones that cause symptoms like shortness of breath. These complications increase the need to learn more about how we can fight it. Recently, researchers around the world have accelerated the search for more treatments to reduce the risks associated with the cardiovascular effects of COVID-19.

Key Highlights

Cardiovascular complications increase the need for more research around COVID-19 and its many symptoms. Learn how cardiovascular conditions are connected to COVID-19 and what treatments are being explored.

PRA Health Sciences
PRA Health Sciences

How Are Cardiovascular Conditions Connected to COVID-19?

Researchers have discovered that COVID-19 causes blood clots in the capillaries in some patients’ lungs. When these tiny blood vessels get blocked, it becomes more difficult for oxygen to get to the lungs, which then causes shortness of breath.

Under normal circumstances, the body can balance forming and breaking up clots on its own. Two proteins, known as tissue plasminogen activator (TPA) and plasminogen activator inhibitor-1, control thrombolysis. COVID-19 makes that more difficult by dramatically raising the levels of both proteins. Critically ill COVID-19 patients often have sticky blood, meaning their blood is prone to clotting, making it difficult for the body to break down clots.

Although researchers have found high TPA and plasminogen activator inhibitor-1 levels in patients, high TPA has been linked to more deaths. However, high plasminogen activator inhibitor-1 can create a bleeding risk in some patients if it disrupts the body’s ability to form clots. For that reason, anticoagulants aren’t always the best option for COVID-19 patients.

No one knows yet why COVID-19 causes blood clotting, though experts have a few theories. It may relate to damaged endothelial cells or tissue damage surrounding them. Another possibility says that the body’s inflammatory response may also trigger clotting as it produces more red blood cells to fight the infection.

Symptoms and Occurrence of Cardiovascular Complications with COVID-19

Issues with clotting from COVID-19 can cause many symptoms that vary between patients, as seen with those who clot too much while others have a bleeding risk from an inability to create clots. Clotting in small blood vessels around the heart and lungs can cause symptoms like:

  • Breathlessness
  • Chest pain
  • Swelling in ankles
  • Heart palpitations
  • Lightheadedness
  • Dizziness

Cardiovascular problems go beyond clotting, too. Researchers have learned that sometimes, the immune system reacts too strongly to the infection, creating a cytokine storm. In these cases, the body releases a large number of cytokines. The resulting overwhelming response can cause organ damage, including to the heart.

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Even people who aren’t at risk of cardiovascular issues can experience them. Most of the time, medical professionals see clotting in hospitalized COVID-19 patients. Approximately 31% of hospitalized patients had high levels of TPA that cause sticky blood from clotting. Meanwhile, 42% of people in a small study of 14 people who had strokes from COVID-19 complications were under 55 and had no stroke risk factors.

Clots can happen in many areas of the body, including the kidneys, gastrointestinal tracts, and extremities. They can cause heart attack, stroke, and pulmonary embolism, along with other serious damage, no matter where they form. Clots in the capillaries can lower oxygen levels and cause problems like “COVID toes,” which creates a painful red rash on the toes. They can also put patients with COVID pneumonia at a higher risk by causing further breathing problems.

What Treatments Are Being Explored?

Researchers are currently looking specifically at treatments for the cardiovascular effects of COVID-19. Much of that research revolves around the use of anticoagulants in combination with other therapies and understanding how different people respond to them.

A study from Cochrane Library has shown that using anticoagulants in COVID-19 treatment lowers the overall risk of mortality in hospitalized patients when compared to having no anticoagulant treatment. The study also showed that therapeutic-dose anticoagulants were more effective at lowering mortality than prophylactic-dose anticoagulants.

Researchers are investigating the use of anticoagulants as a COVID-19 treatment alongside other drugs in the RECOVERY trial. This trial is the largest done for COVID-19 treatments to date. It includes drugs like Azithromycin, the anti-inflammatory Tocilizumab, convalescent plasma, and REGN-COV2, an anti-viral antibody cocktail being investigated for its effectiveness.

Researchers in Australia have made recent breakthroughs in understanding how COVID-19 relates to heart disease. They used bioengineered heart tissue to find that cytokine storms damaged heart tissue even when COVID-19 itself did not affect the heart. Then, they used these organoids to test different drugs on the tissue. As a result, they found that apabetalone, among other drugs tested, worked to block the inflammatory response. Apabetalone specifically has been in clinical trials for the past five years, which means it may be available sooner as a widespread treatment.

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