Postoperative Venous Thromboembolism in IBD: It’s All About the Disease
It has been established that patients with colorectal cancer are at increased risk for postdischarge VTE, and both the National Comprehensive Cancer Network and Chest guidelines4,5 recommend 4 weeks of postoperative VTE prophylaxis. Patients with IBD have twice the risk of VTE compared with the general population,6 possibly related to severity of disease activity. Furthermore, 2 recent studies using National Surgical Quality Improvement Program (NSQIP) database have shown that the risk of postoperative VTE after colorectal surgery in patients with IBD is actually higher than that of patients with colorectal cancer.2,7 Gross et al2 recommended a change in clinical practice to extend postoperative VTE prophylaxis for 4 weeks in patients with IBD who were undergoing colorectal surgery, and Wilson et al7 made a similar recommendation for postoperative patients with ulcerative colitis.
In the current issue of Diseases of the Colon & Rectum, McKenna et al8 analyzed the risk of postoperative VTE in patients with ulcerative colitis (UC) with regard to the specific operation performed using the national NSQIP database. The patients were divided into high-risk, intermediate-risk, and low-risk categories based on procedure Current Procedural Terminology code, which mirrors the amount of disease activity present. Patients with a diagnosis of UC who had intermediate- and low-risk operations had little or no disease activity. Their goal was to determine whether the disease, operative procedure, or both were important factors in determining the incidence of postoperative VTE. Ultimately, these results could guide the use of extended VTE prophylaxis in patients with UC. The authors found that emergent cases and operative procedure (high- and intermediate-risk cases) carry the highest risk of postoperative VTE and recommended that postoperative extended VTE prophylaxis in patients with UC be tailored to these high-risk groups. In addition, they concluded that extended postoperative VTE prophylaxis might be appropriate for all patients undergoing emergent or high-risk colorectal operations independent of the diagnosis.
The results of this study may at first appear to contradict what has been published previously. Wilson et al7 and Gross et al2 concluded that UC or IBD alone is an independent risk factor for postoperative VTE regardless of the operation performed. However, it may not be as black or white as it seems, but rather a shade of gray. It can be postulated that patients who have a higher severity of disease activity require a more extensive operation, leading to an increased postoperative risk of VTE. It is difficult to dissect out whether it is the operation itself, the disease, or both that cause the increased risk of VTE, which makes this somewhat of a gray area as to what exactly is causing the increased risk of VTE. When the emergent cases were removed from the analysis, patients with UC in the high-risk elective group had a statistically significant higher rate of VTE than patients without IBD (4.4% vs 3.2%). This indicates that IBD independently influences the risk of postoperative VTE in patients in the high-risk category, who also have the most severe disease activity.