A Reassessment of Needs and Practice Patterns in Pharmacologic Prophylaxis of Venous Thromboembolism Following Elective Major Surgery

Abstract

Conclusion: Physician judgment should be used in determining susceptibility to venous thromboembolism (VTE) and the need for VTE prophylaxis in patients undergoing major elective abdominal surgery. Summary: There were an estimated 900,000 VTE events in U.S. hospitalized patients in 2005 (Heit JA, et al. American Society of Hematology Annual Meeting Abstract 2005;106 abstract 910). However, pulmonary embolism (PE) after elective abdominal surgery seems very uncommon. Opponents of a “one size fits all” approach to VTE prophylaxis argue routine VTE prophylaxis for all patients increases cost and compromises resources to administer what is potentially a dangerous treatment for an infrequent event in certain categories of patients. They further argue that trials of VTE prophylaxis use some VTE events as end points for efficacy, such as calf vein thrombosis, that may not be clinically significant, at least in the short-term. In 2004 the Kentucky Surgical Care Improvement Project found a very low rate of PE in 5285 elective specialty surgery patients. There were 15 PEs detected in these patients, and none were fatal despite erratic and very limited use of VTE prophylaxis. The authors also queried the University Health System Consortium database from 2004 and also found a very low rate of VTE complication in patients undergoing elective operations (Surg 2008;144:654-660). It is possible, however, that American College of Chest Physicians (ACCP) recommendations may have altered practices of VTE prophylaxis in elective surgical patients, and rates of fatal and non-fatal PE could be influenced by changing indications for VTE prophylaxis. The authors' study was designed to assess and compare rates of VTE prophylaxis and PE from an 18-month consecutive period in 2003 to 2004 with an identical period of observation in 2007 to 2008. Their hope was to assess the effect of the ACCP recommendations advocating an increase in VTE prophylaxis. The authors queried the University Health System Consortium database comprising data from 123 academic teaching hospitals. They identified patients undergoing colorectal resections, total hip replacement, total knee replacement, and hysterectomies from two consecutive 18-month periods: 2003 to 2004 and 2007 to 2008. VTE rates ranged from 0.6% to 3.2%, and PE rates ranged from 0.28% to 1.09%. There was an increased use of VTE prophylaxis for all procedures between 2003 to 2004 and 2007 to 2008, except for hysterectomy. Comparing the two periods, the authors found VTE rates were not significantly affected among patients who received pharmacologic prophylaxis and actually decreased in patients who did not receive any pharmacologic prophylaxis, despite an absence of significant change of severity of illness in the patient populations. Comment: The author's arguments are a step backward from routine VTE prophylaxis to an approach where “the need for prophylaxis would be assessed on an individual basis, based on retrospective data, expert consensus, and clinical judgment.” What the authors may have actually found is that in a practice where VTE prophylaxis is encouraged and withheld only for specific reasons, the rate of VTE complications, specifically fatal PE, is low. It does not follow that the same results can be obtained with the approach of withholding VTE prophylaxis unless one judges it to be specifically required in individual cases.