Mechanical prophylaxis for pulmonary embolism (PE) in the form of an inferior vena cava filter (IVCF) is an option for surgical patients who can't undergo chemical venous thromboembolism (VTE) prophylaxis.
Venous thromboembolism (VTE) stalks surgical patients, taking advantage of various risk factors like advanced age, immobilization, and impaired physiologic reserve. Because of this, between 10 and 60 percent of surgical intensive care unit (SICU) patients ultimately develop VTEs.
During autopsies, pathologists often find clinically unrecognized VTEs, and many researchers believe that current estimates of deep vein thrombosis (DVT) and pulmonary embolism (PE) are low. For this reason, prophylaxis against VTE is used almost universally.
However, surgical patients often can't undergo chemical VTE prophylaxis as a result of significant bleeding risk, recent or imminent surgery, renal insufficiency, anemia, recent history of gastrointestinal hemorrhage, active peptic ulcer disease, or liver disease. In those cases, mechanical prophylaxis for PE in the form of an inferior vena cava filter (IVCF) is an option, despite the present lack of Level 1 recommendations for the use of prophylactic IVCFs in that patient population.
Researchers at Massachusetts General Hospital’s Department of Surgery designed a study to identify independent predictors of VTE in critically ill general surgery patients where chemical prophylaxis was contraindicated. The investigators used the results to identify patients who would benefit from aggressive screening and/or prophylactic IVCF placement.
The study prospectively followed 206 non-trauma patients in the SICU — including patients who had contraindications to prophylactic chemical anticoagulation — for two years.
VTE developed in nearly 10 percent of the patients — a group that was also more likely to have had a previous medical history of PE or renal insufficiency, as well as postoperative blood product requirements where their risk increased as the number of units administered increased. Only one patient who received a prophylactic filter developed VTE, which the researchers interpreted as the possibility that surgeons are placing more IVCFs than necessary.
The authors recommended screening to ensure high-risk patients who may specifically benefit from a prophylactic IVCF are identified, including those who have received transfused blood products within 24 hours of SICU admission, and those who have past medical histories of either renal insufficiency or PE.