In literature several authors highlighted good results with treatment of bleeding even in haemodynamically unstable patients: in particular Monnin et al., with a multidisciplinary approach including embolization, has achieved a 93% success also with haemodynamically unstable patients [14]. Furthermore, in trauma patients who respond to resuscitation treatment, the guidelines of the Eastern Association for the Surgery of Trauma (EAST) in first instance recommend (level 2) arterial embolization, possibly in addition to surgery [15]. Indications for conventional hepatic angiography include active contrast extravasation identified by CECT, evidence of ongoing bleeding despite conservative resuscitative measures, haemobilia and control of continued haemorrhage after surgery. Active bleeding is the leading indication for interventional radiology procedures, in particular as a valid support to the NOM; hepatic angioembolization is usually performed in a dedicated angiographic suite and starts with a retrograde common femoral approach: the goal is to selectively catheterize the hepatic artery and after superselective catheterization reaching up to the site of vascular disease (extravasation, pseudoaneurysm or arteriovenous fistula) to embolize using coils or embolic agents (liquid agents such as Glue and Onyx, gelfoam) (Fig. 22.2).

The most common vascular catheter used for the celiac trunk is Cobra or Simmons shaped; the external size of microcatheters used for superselective catheterization usually has a range from 2.0 to 2.8 French (3 Fr = 1 mm). In case of pre-procedural CT with extensive liver injury, some authors suggest to release embolizing agents such as gelfoam or Spongostan from the hepatic artery of affected lobe even in the absence of angiographic evidence of active bleeding: this however may help in achieving haemostasis and haemodynamic stabilization of the patient; however, it is controversial [16]. In the setting of trauma, the technical success rate of hepatic angioembolization ranges from 88% to 100%, but in cases following surgical packing owing to distorted anatomy and manipulation, technical success rate drops to 60–70% [14]. Usually technical difficulties are related to vascular tortuosity, artery stenosis, most commonly of the celiac trunk, and vessel spasm. In case of complex vascular anatomy, it may help to use smaller size and more navigable microcatheters; similarly, in case of vasospasm, the use of microcatheter and delicate catheter manipulation will help to reach the site of hepatic injury [16]. Lee et al. reported 11 cases of incomplete embolization: ten of these cases were secondary to a persistent contrast blush without an identifiable vessel or a blush supplied by multiple collaterals that could not be embolized, and one reported failure secondary to a stenotic celiac artery [17]. Both Lee et al. and Hagiwara et al. reported failures of NOM despite technical success of angioembolization [18]. Often, the failure of conservative management despite successful angioembolization is related to venous bleeding, that can be difficult to identify during angiography and even harder to treat.

Late liver bleeding is an uncommon (3% of liver trauma) possible complication of NOM [19]. The number of complications is higher in patients with higher degree liver injuries; the most common complications of a hepatic angioembolization include hepatic necrosis, abscess formation and non-target embolization [20]. Due to its vascular conformation, the liver receives constant inflow from both portal and arterial venous vessels. However, despite this robust dual supply, the combined insult of trauma and embolization has been shown to cause significant hepatic necrosis that ranged from 0 to 42% with a weighted mean rate of 15% and was associated with longer hospital stay and increased transfusion requirement [8]. It is evident that liver trauma and subsequent liver devascularization play a major role in hepatic necrosis compared to angioembolization, in particular with a superselective embolization. Green et al. reported that a major degree of arterial selectivity during embolization was generally related to a lower necrosis rate [8].

The next two common complications are abscess formation and bile leak/biloma [21, 22]. These complications are not clearly related to angioembolization and, in literature, they are reported both in operative and non-operative management of hepatic trauma [23, 24]. Probably, hepatic injury and death of a large number of hepatocytes together create a combined state of parenchymal flogosis and tissue necrosis, increasing the risk of abscess formation independently from angioembolization.

Even in the management of complications, interventional radiology through the positioning of percutaneous drainage on abscess sites plays a key role. In a multidisciplinary approach, today the conservative management in patients with liver injury appears a successful algorithm in order to reduce mortality and morbidity rate: angiography and angioembolization are essential components of successful NOM of hepatic trauma patients, as well as a critical component of haemorrhage control following laparotomy [25, 26]. In particular, despite there are no consensus guidelines on appropriate patient selection criteria for those who would benefit from angiography and angioembolization, several articles have suggested that early angiography and embolization improve outcomes in patients with high-grade hepatic injuries [12, 26–30].

In summary, hepatic angioembolization is an effective and important component in the management of traumatic hepatic haemorrhage, also in an operative or non-operative management. Hepatic necrosis is the most important complication and can occur following embolization, but this risk can be safely managed by medical therapy without serious sequelae.

Today interventional radiologists, as real “playmakers” of the multidisciplinary team, play a central role in the treatment of hepatic trauma.