Association between Interruptions in Chemical Prophylaxis and VTE Formation

Abstract

Venous thromboembolisms (VTE) are considered preventable events with appropriate mechanical or chemical prophylaxis. However, chemical prophylaxis is frequently delayed or interrupted during hospitalization. We investigated the impact of delayed initiation and interruption of chemical prophylaxis on VTE rates. The incidence of VTE at an urban academic medical center was measured in patients hospitalized for >2 days between November 2013 and May 2014. Patients receiving prophylaxis were grouped as complete (started within 24 hours of admission and no interruptions), delayed (started >24 hours and no interruptions), and interrupted (interruption for >24 hours with or without delay). There were 9961 hospital admissions and 33 VTE (3.3 per 1000 admissions). 25.2 per cent had complete, 16.4 per cent had delayed, and 11.8 per cent had interrupted prophylaxis. 36.8 per cent received no prophylaxis. Interrupted prophylaxis was associated with more VTE than complete (10.2 vs 2.0 per 1000, P < 0.01) and 5.2 greater odds. Admission to a surgical service and prolonged hospital stay were independently associated with increased likelihood of VTE. There was a lower likelihood of getting complete prophylaxis among patients admitted to orthopedic, transplant, cardiac, plastic, and vascular surgery. Surgical patients are at higher risk for VTE and interruptions in VTE prophylaxis significantly increase the risk of VTE.

Society of Interventional Radiology Clinical Practice Guideline for Inferior Vena Cava Filters in the Treatment of Patients with Venous Thromboembolic Disease

“…Increased risk of PE following injury is consistent with previous studies demonstrating an increased risk of VTE (DVT, PE) when pharmacoprophylaxis is interrupted or delayed for 5 days or greater following injury (35)(36)(37)(38)(39).…”

Updated guidelines to reduce venous thromboembolism in trauma patients: A Western Trauma Association critical decisions algorithm

“…Although the safety and benefit of uninterrupted pharmacologic prophylaxis were established decades ago, more than half of trauma patients encounter interruptions. 79 , 80 A direct correlation is observed between the number of missed doses and DVT risk such that patients who miss two to four doses have 8.5 times higher DVT risk compared with those with no missed doses. 80 For TBI patients who are started on pharmacologic prophylaxis, interrupted dosing causes an approximately 600% increase in the VTE rate.…”

Adequacy of Fixed-Dose Heparin Infusions for Venous Thromboembolism Prevention after Microsurgical Procedures

“…Delay to chemical prophylaxis initiation has been associated with increased risk for postoperative VTE among surgical patients. 15,24 Our study suggests that an initial weight-based heparin dose may allow a larger proportion of patients to have in-range aFXa, or at least would decrease the number of dose adjustments required to achieve goal aFXa levels and time to adequate VTE chemical prophylaxis. Patients who achieved in-range aFXa levels did so on a heparin dose of 8.9 to 18 units/kg/h.…”

“…This is similarly concerning, as delay in prophylaxis is associated with later VTE events. 15 Anticoagulants and antiplatelet agents are used in microvascular surgery to prevent microvascular thrombosis and subsequent flap or replant failure. 5 When utilizing fixeddose heparin infusions to promote microvascular patency, surgeons do not typically provide additional chemical prophylaxis against VTE.…”