Preperitoneal Pelvic Packing for Hypotension: Should There Be a Real Concern for Increased Risk of Venous Thromboembolism?: Commentary on an article by Joseph T. Patterson, MD, et al.: "Preperitoneal Pelvic Packing for Hypotension Has a Greater Risk of Venous Thromboembolism Than Angioembolization. Management of Refractory Hypotension in Closed Pelvic Ring Injury".

Abstract

Commentary Patterson et al. investigated whether there is a difference in the incidence of venous thromboembolism (VTE) in patients with hypotension and pelvic fractures who were managed either with preperitoneal pelvic packing (PPP) or angioembolization (AE). They used the American College of Surgeons Trauma Quality Improvement Program (TQIP) database. The matching of patients was possible using a propensity score approach. The primary outcome was the risk of VTE after matching on the propensity score for treatment, whereas the secondary outcomes included inpatient development of deep vein thrombosis, pulmonary embolism, or respiratory failure, mortality, unplanned reoperation, sepsis, surgical site infection, hospital length of stay, and intensive care unit length of stay. Patterson et al. report that PPP was associated with 9.8% (95% confidence interval [CI], 3.5% to 16.1%) greater absolute risk of VTE (relative risk [RR], 1.5 [95% CI, 1.2 to 1.9]; p = 0.003), 6.5% (95% CI, 1.2% to 11.9%) greater absolute risk of deep vein thrombosis (RR, 1.4 [95% CI, 1.1 to 1.8]; p = 0.04), and 4.9% (95% CI, 0.6% to 9.2%) greater absolute risk of respiratory failure (RR, 3.3 [95% CI, 1.1 to 9.8]; p = 0.03) compared with AE. Interestingly, the incidences of pulmonary embolism and mortality were nearly significant but they were not significantly different by treatment when analyzed separately. The authors conclude that the VTE risk among patients with hemodynamically unstable pelvic fractures was 16% for patients receiving PPP and 6% for patients receiving AE, and this 10% difference in the risk of clinically relevant VTE was attributed to PPP treatment. Patterson et al. cited authors who recommended that screening duplex ultrasounds should be conducted in patients receiving PPP. Although this study raises concerns in relation to the safety of PPP from the VTE point of view, the design and the results must be analyzed judiciously, as it would be unreasonable to develop the view that AE should be given preferential use or even that PPP should not be used, when it has been established for years as an appropriate, lifesaving intervention, especially in situations in which AE may not be readily available. First, of the 29,403 patients who met the inclusion criteria, 366 patients (1.2%) (183 in each group) were suitable for comparison after propensity score matching. That implies that 98.8% of patients were excluded from the analysis. Despite the effort of the authors to match the 2 groups utilizing an optimized propensity score, one remains skeptical whether the 2 groups are indeed comparable, as hypotension was defined as systolic blood pressure of <90 mm Hg at admission before intervention. However, hypotension is a dynamic parameter, and one would have expected patients who then underwent angiography to have achieved hemodynamic restoration (at least a transient response) prior to undergoing the intervention. In contrast, PPP would have been utilized in patients presenting in an extremis (near-death) physiological state, in whom the timing of the intervention is critical, and PPP would have been used as a lifesaving procedure. Therefore, the final suggestion made by the authors to perhaps consider the preferential use of AE, if available, is erroneous. Second, the analysis was based on a small number of VTE events, only 40 in total. Third, the authors themselves highlighted other limitations, including the retrospective nature of the study, the risk of the existence of inconsistent and/or inaccurately coded variables in the database, VTE events occurring after discharge not being captured, the timing of the presentation of VTE possibly being dissimilar between the 2 treatment modalities (PPP and AE), the pelvic fracture type of the injury not being available, and the exact timing of the occurrence of the VTE diagnosis not being able to be determined. Fourth, there was no reference to the incidence of complications that may occur after AE, such as gluteal muscle necrosis, infections, impotence, bladder necrosis, nerve damage, chronic buttock pain, and colonic, ileal, and ureteral infarction, among others1. Taking all of the above into consideration, one may argue that the message of this study must be interpreted with great caution. The 2 procedures should not be considered as antagonists but rather complementary. It should not be forgotten that PPP can address both venous and arterial bleeding, whereas AE can address only arterial bleeding. As previously highlighted according to the PRISM (“Prompt-Individualised-Safe Management”) algorithm of care2, treatment should be individualized on the basis of the availability of local resources, the ongoing evaluation of the hemodynamic condition of the patient, and the expertise of the local surgical team. A prospective randomized study is needed to provide further evidence regarding the controversial finding of this study.