Salt Lake City, UT—Based on standards of care, general surgery patients usually receive anticoagulants before their procedures, in an effort to prevent blood clots.

A report published online by Annals of Surgery questions the practice, however, suggesting that as many as 75% of those patients are receiving blood-thinners they don’t really need.

“A ‘one-size-fits-all approach’ doesn’t always make sense,” explains lead author Christopher Pannucci, MD, an assistant professor of surgery at the University of Utah School of Medicine. “A healthy 35-year-old is very different from someone who is 85 and has a history of clots. Our research indicates that there could be a substantial number of people who are being over-treated.”

For the study, researchers reviewed 14,776 records from 13 research studies to determine which surgical patients were most likely and least likely to benefit from anticoagulants. Patients—who ranged from those with few to multiple clotting risk factors such as obesity, advanced age, and personal or family history of blood clots—were divided into five categories indicating overall clot risk and then assessed using the Caprini score.

Results indicate that, based on that risk stratification, the risk of blood clots varied significantly. Patients in the highest risk group who were not given anticoagulants were 14-fold more likely to develop blood clots than those in the low risk category—10.7% versus 0.7%—no matter what type of surgery they were having.

“It was eye-opening to see that there is this huge variability in risk among the overall group of patients that walk into your office,” Pannucci explained. “Unless you consider a patient's risk based on their individual factors, you would never know.”

Patients with Caprini scores of 7 to 8 had significant VTE risk reduction after surgery with chemoprophylaxis. On the other hand, patients with Caprini scores of <6 made up 75% of the overall population, and these patients did not have a significant VTE risk reduction with chemoprophylaxis, according to the study, which adds that no association between postoperative bleeding risk and Caprini score was identified.

“For the first time we have data that prophylaxis for the highest risk groups is beneficial, and data that suggests that lower risk patients may need no prophylaxis,” noted co-author Peter Henke, MD, a professor of surgery at University of Michigan Health System, who points out that this was an observational study, and prospective trials will be required to prove the results.

Study authors emphasize that that eliminating overtreatment would not only decrease unnecessary costs, but also prevent medical complications in some patients. The research found that just less than 2% of the surgery patients had bleeding complications, with these adverse events significantly increasing in the group given anti-clotting drugs.

“The benefit of peri-operative VTE chemoprophylaxis was only found among surgical patients with Caprini scores ≥7,” researchers conclude. “Precision medicine using individualized VTE risk stratification helps ensure that chemoprophylaxis is used only in appropriate surgical patients and may minimize bleeding complications.”

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