Preop Anticoagulation Safe, Reduces DVTs in Cancer Patients

Roxanne Nelson BSN, RN

December 31, 2015

For patients with cancer undergoing major surgery, the preoperative use of anticoagulants did not increase rates of major bleeding or the need for transfusions, according to new study results published online December 14 in the Journal of the American College of Surgeons.

Administration of an anticoagulant was also associated with a significant decrease in the rates of venous thromboembolism (VTE).

Researchers at Memorial Sloan Kettering Cancer Center (MSKCC) in New York found that rates of deep venous thrombosis (1.3% vs 0.2%; difference, 1.1%; P < .0001) and pulmonary embolism (1.0% vs 0.4%; difference, 0.6%; P = .017) were significantly lower among patients who received preoperative chemoprophylaxis compared with those who did not.

"Our cancer patients are complex and often undergo long surgeries," said study coauthor Vivian Strong, MD, an associate attending surgeon at MSKCC. "But to our surprise and good fortune, we found that preoperative prophylaxis did not increase bleeding."

 
For our institution this has been a practice-changing finding. Dr Vivian Strong
 

"For our institution this has been a practice-changing finding, and it [is] now part of our routine orders sets," Dr Strong told Medscape Medical News in an interview. "We were pleased that at an institutional level, it really made a difference. This new criteria applies to about 80% of our patients."

VTE remains a frequent cause of morbidity during cancer treatment, and although a number of studies have found that postoperative anticoagulation decreases the rate of symptomatic and asymptomatic VTE in surgical oncology patients, the effect of adding preoperative anticoagulation to postoperative VTE prophylaxis is largely unknown, the authors point out.

Study Prompted by Finding from Database Analysis

The impetus to conduct this study came about after researchers at MSKCC analyzed the American College of Surgeons National Surgical Quality Improvement Project database and found that their institution had higher-than-expected rates of DVT and pulmonary embolism.

"We weren't sure how to interpret that," said Dr Strong. "We are a major cancer hospital, and we wondered if the data was properly adjusted for our type of institution and patient population. So we initiated a task force committee to see if we could change our practice and what the outcome would be."

In response to this discovery, the MSKCC VTE Task Force was convened and directed a physician-led prospective quality improvement initiative to investigate the safety and efficacy of instituting preoperative prophylaxis in patients with cancer who were undergoing major surgery.

Lower Rates of VTEs

For this study, Dr Strong and colleagues selected 2058 patients who were undergoing major cancer surgery at MSSKCC to receive preoperative VTE prophylaxis of either low-molecular-weight heparin (40 mg enoxaparin) or unfractionated heparin (5000 units). Anticoagulation was administered in the preoperative holding area by the nursing staff within 2 hours of operation.

Bleeding, transfusion, and VTE rates were compared with those of 4960 historical controls, who had undergone surgery between January 2012 and June 2013 and who did not receive preoperative VTE chemoprophylaxis.

When compared with the control group, patients who received the intervention did not have a statistically significant difference in the rate of major bleeding events (0.8% control vs 0.5%; difference, 0.3%; P = 2).

In addition, they also had lower rates of both documented bleeding (4.2% vs 2.5%; difference, 1.7%; P = .001) and blood transfusion (17% vs 14%; difference, 3.1%; P = .001), as well as lower rates of documented DVT (1.3% vs 0.2%; difference, 1.1%; P < .0001) and pulmonary embolism (1% vs 0.4%; difference, 0.6%; P = .017).

The control group also had a higher rate of missed postoperative VTE prophylaxis doses (3.9% vs 3.3%; difference, 0.7%; P < .0001) and a greater percentage of patients who missed at least one postoperative dose (39% vs 31%; difference, 8%; P < .0001).

Advocate Policy for Other Facilities

"Cancer surgery is among the highest-risk surgery types for VTE, so it is important to have standardized practices in a hospital, such as that displayed here," said Mary Cushman, MD, a professor of medicine in the Hematology/Oncology Division at the University of Vermont, Burlington, who was approached by Medscape Medical News for an independent comment.

"It is also great to see quality improvement research like this being published, because it is valuable to providers and allows other hospitals to copy the protocol that was developed in order to better standardize their own care," said Dr Cushman.

However, she noted that this type of work has caveats because the control group is a historical control group. "As the authors point out, this means that changes in practice patterns like imaging over time, could potentially explain part of the result that was observed in relation to the VTE outcome," she said. "It is also conceivable that changes in practice around transfusion or other issues related to how bleeding was classified and detected could explain the lack of difference in severe bleeding outcomes and lower risk of any bleeding, which was their primary endpoint of interest."

Dr Cushman added, "In a historic controlled study, it is difficult to control for these types of issues, so we can't be 100% sure of the result, but it is likely, as the authors point out, that this practice can be considered safe, and I would advocate other hospitals to employ a protocol like they have done in this specific patient population, if this is not already their routine practice."

This research was funded in part through the National Institutes of Health/National Cancer Institute Cancer Center Support Grant P30 CA008748 to Memorial Sloan Kettering Cancer Center.

J Am Coll Surg. Published online December 14, 2015. Abstract

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