Preoperative use of blood-thinning drugs does not increase major bleeding or transfusion rates, and is associated with a lower risk of blood clots in patients undergoing major cancer operations. These findings are reported online ahead of print in the Journal of the American College of Surgeons (doi:10.1016/j.jamcollsurg.2015.11.011).1
Patients with cancer are at higher risk of deep vein thrombosis (DVT), the consequences of which can be serious. Venous thromboembolism (VTE) is common in patients with cancer, usually occurring in the calf or thigh. When the blood clot breaks free from the leg vein, it can travel to the lungs and cause a potentially fatal blockage in the blood vessels in the lung (a pulmonary embolism).
Administering blood-thinning drugs after surgical procedures is common; however, the safety and efficacy of administering a single dose preoperatively, in addition to postoperative doses, has not been investigated in any large studies. VTE prophylaxis is a common practice in smaller procedures but carries a risk of excessive bleeding, transfusions, and other serious issues.
Prompted by a review of the American College of Surgeons National Surgical Quality Improvement Project (ACS NSQIP) database, and consequent discovery of higher-than-expected rates of DVT and pulmonary embolism at their facility, a research team at Memorial Sloan Kettering Cancer Center (MSKCC) investigated the reasons for their VTE rate and how to lower it.
“There was serious concern that administering preoperative VTE prophylaxis to our patients, who undergo extensive surgical resection, would increase the risk of bleeding. Knowing, from NSQIP, that we had a higher than expected VTE rate, the question was whether it was safe to expose our patients to the additional bleeding risk from VTE prophylaxis,” said Luke V. Selby, MD, the department of surgery’s outcomes research fellow and lead study author.
Selby and colleagues selected 2058 patients undergoing major operations for cancer to receive prophylactic anticoagulation with low-molecular-weight heparin or unfractionated heparin preoperatively; then compared bleeding, transfusion, and VTE rates with those of a cohort of 4960 patients with cancer who had undergone a major surgical procedure a year earlier and had not received preoperative VTE prophylaxis.
Study findings showed that transfusion rates were lower (17% vs. 14%). In addition, significantly lower rates of DVT (1.3% vs. 0.2%) and pulmonary embolism (1.0% vs. 0.4%) were seen. The researchers conclude that providing one dose of an anticoagulant drug before a major operation is safe in patients with cancer. These findings have led to the adoption of a routine anticoagulation approach for select patients undergoing major cancer operations at MSKCC.
1. American College of Surgeons. Preoperative use of blood-thinning drugs is safe for cancer patients [news release]. EurekAlert! web site. http://www.eurekalert.org/pub_releases/2015-12/acos-puo121515.php. Posted December 15, 2015. Accessed December 16, 2015.