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The management of trauma patients has evolved in recent decades owing to increasing availability of advanced imaging modalities such as CT. Nowadays, CT has replaced the diagnostic function of angiography. The latter is considered when a therapeutic option is hypothesized. Arterial embolization is a life-saving procedure in abdominopelvic haemorrhagic patients, reducing relevant mortality rates and ensuring haemodynamic stabilization of the patient. Percutaneous transarterial embolization has been shown to be effective for controlling ongoing bleeding for patients with high-grade abdominopelvic injuries, thereby reducing the failure rate of non-operative management, preserving maximal organ function. Surgery is not always the optimal solution for stabilization of a patient with polytrauma. Mini-invasivity and repeatability may be considered as relevant advantages. We review technical considerations, efficacy and complication rates of hepatic, splenic, renal and pelvic embolization to extrapolate current evidence about transarterial embolization in traumatic patients.
Injuries are the third leading cause of death across all ages.1 Active bleeding is the most common cause of death among trauma patients. While surgery is often considered the definitive treatment for bleeding control, it may not always be the optimal solution for stabilization of a patient with polytrauma. Specifically, arterial haemorrhage arising from pelvic fractures1–3 and solid organ injuries4–6 is amenable to management with angiography and embolization.
Abdominopelvic injuries present a challenge for the emergency department. A multidisciplinary team, comprising an orthopaedic trauma surgeon, a general surgeon, an anaesthesiologist, a radiologist and an interventional radiologist, evaluates each case.
All the protocols5 reported in literature are based on the “damage control orthopaedics (DCO)”;3,6 therefore any intervention, as rapid as possible, should be focused on haemorrhage control and on other life-saving measures. The arterial inflow arrest, pelvic sling and external fixation devices for pelvic fractures, direct surgical haemostasis, angiography and embolization represent treatment options that should be considered for the emergency haemostasis of abdominopelvic traumas.4,5 External devices, easily applied, can be used effectively.3–6
Owing to the lack of randomized trials evaluating the efficacy of arterial embolization in the trauma setting, the Eastern Association for the Surgery of Trauma guidelines offered Level 2 recommendations for angiography and embolization as a first-line treatment of liver injuries “for a patient who is a transient responder to resuscitation as an adjunct to potential operative intervention”.7
The purpose of this study was to evaluate and review indications, techniques, results, complications and future developments in utilization of angiography and embolization for abdominopelvic traumatic patients.
A review of international literature on abdominopelvic traumatic lesions, pelvic ring fractures and angioembolization was carried out through PubMed with the following medical subject heading: “blunt abdominal/liver/spleen/renal trauma”, “retroperitoneal bleeding/trauma”, “pelvic fractures/injury/trauma/bleeding” and “transarterial embolization/interventional radiology”.
All titles and abstracts of studies identified in the initial search were screened to identify those reporting on patients with traumatic lesions of solid organs or pelvic bleeding undergoing transarterial embolization (TAE) as one of the initial life-saving interventions. We identified additional studies through hand searches of bibliographies from primary studies, review articles and key journals. Case reports, small series revisions and articles that contained data reported previously were excluded and only articles in the English language or published after 2002 were included. Articles were considered eligible for inclusion in the present review if at least one outcome of interest was described; if articles dealing with traumatic and non-traumatic causes of bleeding, traumatic patients were extracted.
The following variables were extracted, where available, from the included articles: number of patients; trauma and its grading on the basis of American Association for the Surgery of Trauma Organ Injury (AAST),10,11 associated lesions, injury severity score (ISS),12 number of sessions of treatment, embolic agent used, technical success, clinical success, rebleeding rate, complication and mortality rate. Data are reported as described in the studies: authors sometimes reported a range and/or a median value and sometimes reported a rate and/or a value.
Before extracting data from the eligible studies, clear definitions of all outcomes of interest were established. Efficacy rate of TAE was defined as the frequency of successful embolizations in each study. Successful embolization was defined as cessation of contrast medium extravasation in post-TAE imaging without any need for further intervention (repeat TAE or surgical approach), as clearly mentioned in each manuscript. Mortality was defined as early patients’ death before discharge, with the following causes: persistent haemorrhage, concomitant trauma and complications (adult respiratory distress syndrome, multiple organ failure, sepsis). Mortality due to all above causes was defined as overall mortality. Angio-related complications were those associated with the angiography and embolization procedures, such as major puncture site complications (haematoma, infection, femoral artery dissection, aneurysm or pseudoaneurysm formation, a–v fistula, leg ischaemia); gluteal muscle, bladder or intestinal necrosis; liver or renal failure, ischaemia of the gallbladder, abscesses of large necrotic areas (hepatic, splenic or retroperitoneal), major allergic reactions.
The AAST grade of liver injury was reported in almost all the studies,13,15,17,20–22 in particular in a total of 172 patients, as reported below, 18 Grade II, 53 Grade III, 77 Grade IV, 23 Grade V injuries.
In almost all the studies,14–16,18,20–22 materials used to embolize were coils, gelfoam and polyvinyl alcohol particles (PVA). The choice of the materials used to embolize was based on the operator's preference and expertise (Figure 2a–c).
Complications were reported in nine studies.14–22 Complications have been described differently; on the basis of the definitions of the present review, complications related to embolization were gallbladder infarction, hepatic necrosis, liver abscess described by Kong et al.21 Monnin et al15 registered two cases of gallbladder infarction but they did not attribute it to embolization.
Most of the complications described were managed conservatively; cholecystectomy was performed when necessary.15 Misselbeck et al16 described nine complications after TAE (three managed operatively) and in total they described only one death related to liver failure.
The overall mortality rate was usually related to concomitant trauma or to uncontrolled haemorrhage (Table 1).15–19,22 Embolization was never described as a direct cause of death, it may be considered as a co-factor (for example, the death described by Misselbeck et al16 for liver failure or the two deaths for liver infections reported by Lee et al22).
We identified 20 studies,23–42 involving a total of 939 patients who underwent splenic angioembolization (SAE) for traumatic lesions (Table 2). All 20 studies that were included were retrospective cohort studies.
All included patients sustained blunt mechanism of injury, and the overall mean America Association for the Surgery of Trauma Organ Injury (AAST)–Organ Injury Scale (OIS),6,8 AAST-OIS grade of splenic injuries was 3.65. In the table, mean value is indicated because most of the studies reported it.
SAE could be distal (selective), proximal (splenic artery) or combined.43 Proximal embolization was performed significantly more often than distal embolization (601 patients vs 144 patients; 64% vs 15.33%).23–25,27–40 A combination of both techniques was applied in only 30 patients (3.19%).23–25,27–40 In 164 patients (17.35%), SAE procedure was not described in detail (three studies)26,41,42 (Figure 3a–e).
In some studies,26,27 the effectiveness of SAE could be masked when the outcomes of patients treated with observational management and SAE are combined in terms of non-operative management. Average rate is 84.6%.
In 60 cases (6.38%), bleeding recurrence was observed;24,25,27–32,34,36–40 Haan et al32 observed 27 persistent splenic pseudoaneurysm (PSA) and 5 new splenic PSA after first coil embolization. In a total of 25 patients,32 splenectomy was required (splenectomy was required for infectious complications in 4 patients), and in 4 patients, splenic angiography was performed again,32 with a mean SAE failure rate of 14.67% and clinical success ranged from 67.6% to 100% (mean 84.33%). Other complications described were splenic abscess, delayed splenic infarction, splenic artery dissection, femoral artery dissection and femoral arteriovenous fistula, coils migration (Table 2).27,30,33,42
Smith et al30 failed non-operative/SAE management in 27% of patients. None of the patients (n=9) with low-grade injury (I, II) and mild or absent haemoperitoneum failed transarterial embolization, whereas 10 of the 23 patients (43%) with high-grade injury (III, IV, V) and moderate or large haemoperitoneum failed.
Mechanism of injury was not specified in three studies.54,55,59 When reported,44–53,56–58,60–63 the cause was blunt renal trauma (majority caused by motor vehicle accidents) in 87.4% of the cases and penetrating injuries (gunshot or stab wounds) in 12.6% of the cases.
The AAST grade of renal injury was reported in almost all the studies as reported below: 9.1% Grade II injuries, 18.2% Grade III, 50.48% Grade IV, 22.59% Grade V injuries.
Mean ISS was reported in only eight studies,50–52,55,58–61 having an overall mean value of 23.37. The most frequently associated lesions were pelvic bleeding in 23.4% of the reported cases, thorax injuries in 23.4% of the cases, spleen injuries in 21.2%, liver injuries in 17% and central nervous system injuries in 14.8%.
In half of the studies,48,50,54,55,57–60 there were no reported data on the materials used to embolize. However, in the studies44–47,49,51–53,56,61–63 that reported embolic materials they were distributed as follows: 47.8% coils, 21.7% coils and gelfoam combined, 18.4% only gelfoam, 6.5% glue, 3% Onyx, 2% PVA. The choice of the materials used to embolize was based on the operator's preference and expertise (Figure 6a–e).
Technical success was 96.2%. Clinical success was 90.92%. Rebleeding rate was mostly reported,44–48,50–58,60–63 having an overall rate of 25.6%. The overall mortality rate was 8.5%.44–48,50–56,58,61–63
Mechanism of injury was not always reported.65,67–69,72–75 When reported,3,64,66,68,70,71,73,74 the major cause was motor vehicle accidents; pedestrian accidents, crushs, falls, train accidents and stabbings were the less frequently reported causes.3,64,66,68,70,71,73,74 The AAST grade was not specified;3,64–75 in some studies,66,68–70 patients were haemodynamically unstable. Haemodynamic instability was defined as systolic arterial pressure <90mmHg after an additional infusion of normal saline (generally 500–1000ml) and a continuous infusion of dopamine was started.1,10,12 In most cases, thoracic and abdominal bleeding, cardiac tamponade and pneumothorax tension were investigated simultaneously to pelvic haemorrhages.64,67–75 Laparotomy was indicated by concomitant haemodynamic instability and progressive abdominal effusion or by the existence of a pneumoperitoneum. The most frequently associated lesions were multiple lesions, in particular involving abdominal organs.64,67–75
In the case of combined intraperitoneal and retroperitoneal bleeding, the attending physician could choose pelvic angiography or exploratory laparotomy as the first-line treatment.76
In most studies,65,66,68,69,71–75 there were no reported data on the materials used to embolize. However, in the studies3,64,67,70 that reported embolic materials they were coils, gelfoam, coils and gelfoam combined, particles and plug3,64,67,70 (Figure 8a–e). The choice of the materials used to embolize was based on the operator's preference and expertise. Technical success was reported in 11 studies;3,68–75 the overall rate is 98.9%.
Clinical success was reported in 10 studies;3,64,67–73,75 the overall rate is 91.75%. Rebleeding rate was reported in 10 studies,3,64,67–73,75 having an overall rate of 9.7%. Among the cases of rebleedings, some were from new sites or from controlateral sites.72,75
The main purpose of the present review was to evaluate and analyse indications, techniques, results, complications and future developments of arterial embolization in abdominopelvic haemorrhages.
In the last years,77 a significant decreasing utilization for angiography was registered. Improved patient selection for angiography may have been a factor contributing to decreased use.
Contrast-enhanced CT has revolutionized the diagnosis, management and treatment of trauma patients, demonstrating most of the lesions in a single examination.
Whole body contrast-enhanced CT should be the first-line imaging modality in severely injured patients who respond at least partially to resuscitation.
Early whole body CT improves outcome, shortening the decision time. Its aim is to indicate whether haemostatic control is best achieved by non-operative management, interventional radiology or damage control surgery.
The Eastern Association for the Surgery of Trauma first published guidelines for the management of haemorrhage in patients with pelvic fractures in 2001.78
The same group published the first set of guidelines for the management of hepatic injuries in 2003; an update in 2012 gave similar recommendations for the role of angiography.7 In the same year, the same group published guidelines for non-operative management of blunt splenic injury.79 Four years before, Raikhlin et al80 had already reviewed literature about splenic embolization focusing to its technique (proximal, distal, combined), its efficacy and safety and residual splenic immunological function and risk of infection.
In 2012, Cardiovascular and Interventional Radiology Society of Europe published guidelines for endovascular treatment of traumatic haemorrhage76 on the basis of those proposed by Oxford Centre for Evidence-based Medicine. Interventional radiology and imaging play an important role in severely traumatic patients, as this document shows.
All included studies were case series: a clearly defined protocol for angiographic intervention was missing, and incomplete description of all outcomes of interest was available. Studies were clinically and methodologically heterogeneous, on the basis of different design, conduct, demographic factors, therapeutic interventions, resuscitation data and outcomes, as consequence bias in the results are inevitable. Moreover, some studies include haemorrhages with different causes, and we extrapolated traumatic patients and data about procedures, results, outcomes and complications; possible errors of interpolation and/or interpretation should be considered.
The lack of randomized control trials does not allow one treatment method to be stabily superior over the other. However, the review of case series about abdominopelvic traumatic lesions of the last 13 years confirmed TAE as a highly effective technique in controlling life-threatening haemorrhages.
Efficacy rate was based on three substantive criteria: cessation of contrast extravasation on post-TAE angiography; improvement of patients’ haemodynamics; and avoidance of further interventions to control exsanguination from the districts examined (no further TAE or urgent laparatomy/pelvic packing). Technical success, clinical success and rebleeding rates resulted high in all the districts considered, in particular ranged from 93.3% to 98.9% (splenic and pelvic embolization, respectively), from 79.8% to 91.75% (liver and pelvic embolization, respectively) and from 6.38% to 25.6% (splenic and renal embolization, respectively). Most of the studies16,18,48,62,72,73 recorded high percentages of other arterial bleeding sites than the ones initially embolized, probably for the profuse vasoconstriction during the initial shock state that had obscured arterial bleeding sites during the primary angiographic procedure. It is unclear whether an open approach (instead of TAE) could have resulted in a more efficacious haemorrhage control with less complications in recurrent bleeding, either from the primarily embolized site or from new arterial bleeding sites.
Overall mortality can be attributed to massive uncontrolled haemorrhage; concomitant trauma; lethal complications (adult respiratory distress syndrome, multiple organ failure, sepsis). Our data about overall mortality are heterogeneous therefore an overall value cannot be given. Deaths related to the procedure of embolization are not reported; furthermore, some authors65 did not indicate the cause of deaths registered. Other authors attributed mortality to concomitant trauma and/or to systemic complications; many factors should be considered (polytrauma situation and ISS, and indirect blood loss and concomitant transfusions).3,82 Timing of TAE could be another important factor but we did not analyse it because very few studies reported mortality (or efficacy rate) with respect to timing of TAE.
Few studies provided data on angio-related complications. Complications should be divided in that of arterial access (haematoma, femoral artery arteriovenous fistula, pseudoaneurysm, etc) and of the artery affected (dissection, rupture, etc) and that are consequent of the embolization (infarction, necrosis, abscess, etc).
The latter were described in all districts; some of them may be easily managed; an example may be cholecystectomy after gallbladder infarction; others, like liver or splenic abscesses are more severe. In these patients, the initial extent of haemorrhagic damage should be considered before to attribute abscess, necrosis and organ failure (in the case of liver) to TAE. These data are not available but sometimes only deductible from the entity of trauma (when reported) and consequently it can not be trusted.
Non-target embolization was described only in a series of the (Table 2).27 Muscle necrosis was described in pelvic embolization, but it is unknown if another approach would have avoided this complication.
In conclusion, TAE seems to represent effective acute interventions for arterial haemorrhage control in the context of abdominopelvic trauma and could potentially reduce relevant mortality rates. Haemodynamic stabilization of the patient should be considered the main purpose of TAE.
The necessity of a subsequent surgical revision depends on several factors, in most cases not dependent on unsuccessful TAE, as the present review demonstrated. Only randomized control trials could confirm the data reported. Nevertheless, randomized trials are very difficult to perform in emergency settings.