Surgical patients who have recently had Covid-19 appear to have a higher risk of blood clots after their operation, a study suggests.
Researchers said increased surveillance of patients should be considered so they could get prompt treatment.
A team of researchers, led by experts at the NIHR Global Health Research Unit on Global Surgery in Birmingham, examined data on patients who needed both emergency surgery and pre-planned surgery in October 2020 to see whether they went on to develop a venous thromboembolism (VTE) in the month after their operation.
Academics examined data on more than 128,000 patients from 1630 hospitals across 115 countries.
Overall, 742 patients went on to develop a post-operative VTE – either a deep vein thrombosis, a pulmonary embolism or both.
Patients who were infected with the virus which leads to Covid-19 – Sars-CoV-2 – around the time of their operation were 50% more likely to have a VTE in the 30 days after their operation.
Those with a recent infection – within six weeks of their operation – had a 90% increased risk, according to the study published in the journal Anaesthesia.
Those who had a VTE around the time of their operation were also more likely to die in the 30 days after their operation compared with those who did not.
Co-author Elizabeth Li, general surgery registrar at University Hospital Birmingham, said: “People undergoing surgery are already at higher risk of VTE than the general public, but we discovered that a current or recent Sars-CoV-2 infection was associated with greater risk of post-operative VTE.
“Surgical patients have risk factors for VTE, including immobility, surgical wounds and systematic inflammation – and the addition of Sars-CoV-2 infection may further increase this risk.”
Co-author Aneel Bhangu, consultant colorectal surgeon from the University of Birmingham, said: “Increased awareness and surveillance should be considered.
“At a minimum, we suggest close adherence to routine standard VTE prophylaxis for surgical patients, including the use of anti-clotting medication when bleeding risk is minimal, and increased vigilance and diagnostic testing in patients presenting with signs of VTE, such as swelling in one calf, right-sided chest pain and shortness of breath.”