A recent study found that individuals infected with or who have survived COVID-19 are at an increased risk of developing severe blood clots after undergoing surgical procedures. Researchers from the University of Birmingham in England concluded that there is a connection between the diagnosis of COVID-19 in individuals, whether it was a past or current infection, and the development of venous thromboembolism (VTE), a serious form of blood clot, that may occur after surgery. Those who contracted COVID-19 in the six weeks prior to their surgery were found to be twice as likely to experience venous blood clots.
The team of scientists, in a study published in the journal "Anesthesia," gathered data from 128,013 patients who underwent various types of surgeries in 1,630 hospitals across 115 countries. They classified the patients into four categories: those who never had COVID-19, those with an "active" COVID-19 infection, those who had recently contracted the virus specifically within the past six weeks, and a group of prior cases made up of individuals who contracted the virus seven weeks or more ago.
The aim of the study was to determine how many patients developed venous thromboembolism within 30 days post-surgery, as reported by the British newspaper "Daily Mail." In the first group, 666 out of 123,591 developed deep vein thrombosis, which is 0.5 percent of the study participants. Among those who underwent surgery with an active COVID-19 condition, 50 out of 2,317 were found to have blood clots, equating to 2.2 percent. Among 953 patients who had recently experienced COVID-19 but had recovered, 15 developed venous blood clots, or 1.6 percent. Finally, about 1 percent of patients with a previous COVID-19 history, specifically 11 out of 1,148, developed clots.
The researchers adjusted the data for other factors that could contribute to the development of blood clots, such as age and prior clotting history. After these adjustments, it was determined that those with a recent COVID-19 infection were 90 percent more likely to develop venous blood clots. Patients with active COVID-19 were found to be 50 percent more likely to experience VTE, while those with a previous infection were 70 percent more susceptible.
Across all groups, there was a correlation between past COVID-19 infection and the development of post-surgical complications later on. Dr. Elizabeth Li, a co-author of the study at the University of Birmingham, stated, "Individuals undergoing surgery face a risk of developing venous blood clots, but we found that having COVID-19 may increase this risk." The study also revealed that the risk of death following the development of venous thromboembolism increases by 450 percent for COVID-19 patients. It was noted that among 76 patients in the study who had COVID-19 and developed venous blood clots, 31 of them (40.8 percent) ultimately died, compared to only 319 of 4,342 patients who did not experience venous blood clots (7.4 percent).
