Blood clots are the latest threat to coronavirus patients
When Broadway actor Nick Cordero had his leg amputated following complications from COVID-19 it came as a shock to many. But for health-care professionals and researchers investigating COVID-19 this was a confirmation of what they already knew: dangerous and potentially life-threatening blood clots are a hallmark of COVID-19.
Thrombosis is an excessive level of blood clotting that stops the flow of blood to parts of the body. In COVID-19 patients, two forms of thrombosis have emerged as common complications. Deep vein thrombosis is a blood clot that forms in the veins. DVT often occurs in the legs and can cause tissue damage that is severe enough to require amputation. A blood clot that travels to the lungs creates a pulmonary embolism, which is a potentially fatal condition that reduces the uptake of oxygen.
Early studies from China reported that markers for the risk of blood clots were unusually high in patients admitted for COVID-19. Similarly, studies from Italy found that COVID-19 patients with no history of clotting disorders or blood conditions exhibited risk factors for blood clots. Studies from the Netherlands and China found that 25 to 30 per cent of COVID-19 patients have dangerous blood clots. As alarming as these numbers are, researchers think thrombosis is under-diagnosed in patients with COVID-19.
The risk for blood clots is typically higher in critically ill patients with infections. Blood clotting is normally a natural defence mechanism to limit the spread of the pathogen. But with severe infections the virus can damage blood vessel walls and increase the risk of blood clots to a dangerous level. The immune system can be overstimulated and cause excessive blood clotting.
The link between infections and thrombosis is well known, but SARSCoV-2 infection elevates the risk higher than usual. More concerning are reports that standard treatments to reduce blood clots do not appear to be very effective. A recently published study by showed that even with anticoagulant therapies, the rate of pulmonary embolism is five-times higher in COVID-19 patients compared to others hospitalized with non-COVID -19 respiratory infections.
While health-care professionals struggle to understand and treat the epidemic of blood clots that endanger the lives of COVID-19 patients, another threat looms on the horizon. The HIV therapy lopinavir-ritonavir is currently under investigation in clinical trials for COVID-19 treatment. Previous studies show that lopinavir-ritonavir can interfere with common blood clotting medications including Plavix, Eliquis, and Xarelto. This means that patients who are already at high risk for blood clots may experience a doubly increased risk in the form of the viral infection and the treatment that interferes with the medications they are taking to decrease blood clots.
Blood clots are just the latest cardiovascular complication to emerge in COVID-19 patients. Within weeks of identifying the novel SARS-CoV2 virus, clinicians reported that patients with underlying cardiovascular disease were dying from COVID-19 at a rate that was 50 per cent higher than that of individuals with chronic respiratory disease. Even in patients without pre-existing heart disease studies show that the virus damages the heart.
COVID-19 is more than just a respiratory infection. Its ability to wreak havoc across multiple systems in the body is a demonstration of the battle health-care professionals face in treating this new and dangerous virus.