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EVIDENCE BEHIND THE USE OF EXTENDED VENOUS THROMBOEMBOLISM PROPHYLAXIS IN COLORECTAL SURGERY: A SYSTEMATIC REVIEW
Lauren Weaver
*1, Lindsay Welton
1, Alexander Troester
1, Julia Kohn
1, Nicholas Klemen
2, Cyrus Jahansouz
1, Mary Butler
1, Bronwyn Southwell
1, Paolo Goffredo
11University of Minnesota Twin Cities, Minneapolis, MN; 2National Institutes of Health, Bethesda, MD
Background: Current guidelines recommend 4 weeks of extended chemical venous thromboembolism (VTE) prophylaxis for patients undergoing colorectal surgery for cancer or inflammatory bowel disease (IBD). However, evidence supporting the benefit of extending VTE prophylaxis outside the immediate postoperative period is limited. Meanwhile, adverse events from extended prophylaxis such as increased bleeding risks, higher healthcare costs, and frequent injections negatively impact patients’ quality of life. Therefore, we conducted a comprehensive systematic review to assess evidence behind the use of extended VTE prophylaxis to better inform postoperative care.
Methods: Medline®, Embase®, and CENTRAL databases were queried between January 1946 and May 2023 to identify randomized control trials (RCTs) or non-randomized study interventions (NSRIs) evaluating VTE rates +/- extended chemoprophylaxis after colorectal surgery at ?30 days follow-up. Primary outcome was overall VTE rate, including asymptomatic and symptomatic VTE. Individual study risk of bias (ROB) and overall strength of evidence (SOE) was assessed using standardized methods.
Results: We identified 37 eligible studies (4 RCTs and 34 NSRIs), and 14 were deemed low/moderate risk of bias. Median VTE rate after colorectal surgery +/- prophylaxis was 1.9% (IQR 0.7-2.9;30 studies n=754,538, moderate SOE). In colorectal cancer patients, median postoperative VTE rate was 1.6% (IQR 0.6-2.8;24 studies n=243,433, moderate SOE) with symptomatic VTE rate of 0.6% (IQR 0.25-2;16 studies n=18,622, moderate SOE) compared to asymptomatic VTE rate of 0.9% (IQR 0-4;6 studies n=2,210, moderate SOE). For surgical IBD patients, overall VTE rate was 2.1% (IQR 1.0-3.2;9 studies n=80,546, moderate SOE). Compared to inpatient chemical prophylaxis alone, extended prophylaxis in colorectal cancer patients may reduce overall VTE (low SOE), symptomatic VTE (low SOE), and DVT rates (low SOE; Table 1), while there was no difference in PE rates or VTE-related deaths (low SOE, Table 1). Extended prophylaxis did not increase major bleeding or postoperative transfusion rates (low SOE). Evidence was insufficient to determine outcomes of extended vs inpatient only chemical prophylaxis for surgical IBD patients.
Conclusions: These results indicate symptomatic VTE rates after colorectal surgery are as low as 0.6% in cancer and IBD patients, groups historically considered high-risk. There may be a benefit for extended prophylaxis after colorectal cancer surgery, although of very limited magnitude, with heterogeneous and low quality evidence. Meanwhile, evidence to support extended prophylaxis in IBD patients is insufficient with no current comparison studies. To better inform guidelines, adequately powered clinical trials comparing extended vs inpatient chemical prophylaxis are greatly needed to evaluate efficacy and adverse effects.
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