Nikhil Prasad Fact checked by:Thailand Medical News Team Oct 16, 2026 52 minutes ago
COVID-19 can trigger dangerous blood clotting abnormalities that extend far beyond the lungs, increasing the risk of pulmonary embolism, stroke, heart damage, and death. A new scientific review highlights how severe inflammation disrupts normal blood clotting and why complications can persist after hospitalization.
Scientific review reveals how severe COVID-19 triggers dangerous blood clots, damages blood vessels, and increases
the risk of potentially fatal complications.
Researchers from Shahid Beheshti University of Medical Sciences, Semnan University of Medical Sciences, and Iran University of Medical Sciences, Iran, examined published evidence from December 2019 through May 2026.
Severe COVID-19 Dramatically Increases Blood Clot Risks
The review found that coagulation abnormalities affect approximately 20% to 50% of hospitalized patients with severe COVID-19.
Venous thromboembolism, involving potentially dangerous blood clots, occurs in approximately 5% to 15% of general hospital ward patients, compared with 25% to 45% of intensive care patients.
Pulmonary embolism and deep vein thrombosis are particularly concerning. Patients developing thrombotic complications face substantially higher mortality risks.
Blood Tests Reveal Important Warning Signs
A major finding highlighted in this
Thailand Medical News report involves D-dimer, a blood marker indicating clot formation and breakdown.
One study found average D-dimer concentrations of 2.12 mg/L among patients who died, compared with 0.61 mg/L among survivors.
Another analysis associated admission D-dimer levels exceeding 1 mg/L with approximately 18-fold higher odds of death.
Other abnormalities included prolonged clotting times, mildly reduced platelet counts, and elevated fibrinogen levels.
How COVID-19 Damages Blood Vessels
Researchers identified excessive inflammatory signaling, endothelial injury, and immune system activation as major contributors to abnormal clotting.
Immune cells release sticky structures called neutrophil extracellular traps, which encourage platelets and clotting proteins to accumulate inside blood vessels.
Autopsy evidence revealed microscopic lung clots occurring nine times more frequently in COVID-19 patients than influenza patients.
The review also highlighted stroke, intestinal ischemia, and cardiac complications. In one hospitalized cohort, mortality reached 51.2% among patients with cardiac injury, compared with 4.5% without cardiac injury.
Treatment Requires Careful Anticoagulation
Heparin-based medications remain important for preventing blood clots in hospitalized patients.
However, higher anticoagulant doses do not consistently improve survival among critically ill patients and can increase serious bleeding.
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Researchers emphasized individualized treatment based on clotting markers, disease severity, and bleeding risks.
Conclusion
The findings demonstrate that severe COVID-19 involves dangerous interactions between inflammation and blood clotting. Careful monitoring, appropriate anticoagulation, and continued assessment after hospitalization could help reduce complications. However, the review synthesizes existing studies rather than establishing new clinical trial evidence.
The study findings were published in the peer reviewed Medical Journal of the Islamic Republic of Iran.
https://mjiri.iums.ac.ir/article-1-10010-en.html
Read Also:
https://www.thailandmedical.news/articles/coronavirus
https://www.thailandmedical.news/articles/long-covid
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