Patients who currently have COVID-19 or have had a recent infection are at a higher risk of developing venous thromboembolism (VTE) during surgery, according to a recently published study in the journal Anaesthesia.

The rate of VTE in COVID-19 patients was evaluated in a multicentre, prospective study, which included 128,013 patients undergoing elective or emergency surgery for any indication, from any specialty from 1630 hospitals across 115 countries. The patients were categorised into four groups according to their COVID-19 status as defined in the study: peri-operative (7 days before to 30 days post-surgery), recent (1-6 weeks prior to the surgery), previous (≥7 weeks before surgery) and no COVID-19.

Overall, VTE occurred in 742 (0.6%) patients; out of which 329 patients had pulmonary embolism, 352 had deep vein thrombosis, while 61 patients had both. A larger number of patients with recent and peri-operative COVID-19 infection developed VTE. The postoperative VTE rate was 2.2% in peri-operative COVID-19, 1.6% in cases with recent infection and 1.0% in those who had a prior infection. The VTE rate was 0.5% in patients who had not suffered COVID-19 at any time.

Compared to patients with no VTE, post-surgery 30-day mortality was found to be higher those who developed VTE. In patients with COVID-19, mortality without VTE was 7.4% and with VTE it was 40.8%.

Older age (>50 years), peri-operative and recent SARS-CoV-2 infection, pneumonia, American Society of Anesthesiologists (ASA) physical status 3–5, chronic kidney disease, any major surgery, emergency surgery, surgery for malignancy or trauma, general anesthesia were found to be predictive of postoperative VTE.

Patients undergoing a surgical procedure are already at risk of VTE. Several factors such as immobility, the surgery itself (type of surgery and duration of the procedure), dehydration, sepsis influence this risk. COVID-19, which is a hypercoagulable state in itself, further adds to the risk. This study has demonstrated that a current or recent SARS-CoV-2 infection was associated with greater risk of postoperative VTE.

The risk of VTE must be assessed in every surgical patient. There is also a need to maintain constant vigil, especially in those with risk factors. Hence, strategies to reduce the risk of VTE should be part of routine postoperative care of patients. A high degree of suspicion coupled with diagnostic testing in the presence of signs of VTE, especially during the ongoing pandemic where some patients could also harbor asymptomatic infection, would significantly lower the associated morbidity and mortality.