Pelvic fractures may be accompanied by hemorrhage, which can lead to hemodynamic instability and death. At our institution, AE intervention is a standard procedure in this setting and is associated with good bleeding control outcomes [8, 10]. Furthermore, delayed angiography in these patients may be associated with poor outcomes [8, 15, 16]. Technological improvements and increased availability have led to an increasing number of vascular injuries being identified during CT examinations, although recent studies have indicated that imaging-based evidence of CE does not necessarily indicate a need for AE to control bleeding [4, 17-19]. Thus, a rapid AE intervention following pelvic fracture might not be an optimal step during the chaotic resuscitation process. Although AE can be promptly performed at our center (a mean time of 60 min from order to procedure), the main diagnostic tool was CT, which had a low PPV, and the high incidence of SSIs following nBIIAE was suboptimal. For example, 82.4% of patients in the AE group exhibited signs of arterial bleeding during the CT examination, while only 26% of patients exhibited signs of CE during angiography. This corresponds to a PPV of only 29.6% for using CT to detect arterial injury in patients with pelvic fractures, which is similar to the results from previous studies [20, 21]. We suspect that the presence of contrast extravasation may be difficult to differentiate between bone marrow and arterioles during CT examination soon after a pelvic fracture. Furthermore, our results suggest that evidence of CE during CT may not be a suitable major indication for AE, despite this being previously reported [7, 22]. Dreizin et al. [27] have suggested that the use of AE should be instead guided by the hematoma volume when arterial bleeding is detected during CT. We believe that angiography and AE should be performed more selectively, such as based on non-response to resuscitation, a continuing decrease in hemoglobin concentration without evidence of bleeding from other sources, and the absence of arterial blush during CT.
Non-selective embolization is considered a hemostatic procedure for hemodynamically unstable patients with pelvic fractures [7, 23], although recent studies have focused on selective or super-selective embolization to decrease the negative effects of non-selective embolization in cases of vasospasm or rich collateral arterial networks within the pelvis [24, 25]. Thus, we evaluated the outcomes of different AE strategies, given the fact that AE interventions might be accompanied by a high complication rate after these patients undergo osteosynthesis to treat their unstable pelvis. The present study revealed that 74% of patients underwent nBIIAE as their AE intervention and 9 of 11 patients who experienced SSIs after AE and osteosynthesis had undergone nBIIAE. Local soft tissue injuries after high-energy trauma, such as Morel- Lavallée lesions, might have contributed to the incidence of SSIs, although it would also be prudent to consider the potential contribution of nBIIAE.
Contrast-enhanced CT scans have become routine at many institutions, including our institution, to detect arterial bleeding within the pelvis [26]. However, relative to angiography as the gold standard, CT had a low PPV and a high NPV for detecting arterial bleeding. In addition, we observed that patients with no signs of CE during imaging had a significantly higher mortality rate after AE, relative to patients with signs of CE during CT (30.0% vs. 11.0%, p = 0.03). Moreover, there were no significant differences between the two groups in terms of age, sex, ISS, time to the AE, fracture classification, the volume of blood transfusion, and the rate of repeat AE. We speculate that patients without signs of CE during CT would have been experiencing shock due to sources other than arterial injury, such as cancellous fracture surface bleeding or venous plexus bleeding. As a result, AE would provide limited benefits in these patients, while delaying the resuscitation procedure and potentially increasing the risk of mortality. Therefore, AE should not be a routine procedure for hemodynamically unstable patients with unstable pelvic fractures, and other hemostasis procedures, such as PPP, should be considered during the resuscitation process for these patients.
Although we made every effort to reduce the influence of bias in this study, it has several limitations. First, the retrospective design is inherently associated with risks of bias, and we observed that cases that underwent AE were more severe and had higher ISS scores than the non-AE cases. Thus, the higher complication rate in the AE group might reflect the severity of the patients’ injuries, and strict selection criteria may be needed for the AE procedure to avoid further complications that are difficult to manage. Second, although our center uses an established protocol to identify patients who should undergo angiography, the choice of selective or non-selective embolization was based on the radiologist’s discretion. The interventional radiologists commonly noted that non-selective embolization was performed “to facilitate hemostasis”, even when no arterial bleeding was identified during angiography. Third, AE has been performed at our center during the last two decades as part of a fixed protocol for hemodynamically unstable patients with pelvic fractures, and it may be difficult to encourage experienced emergency traumatologists to include PPP as an alternative strategy in our resuscitation protocol.