Impact of site of occlusion in proximal splenic artery embolisation for blunt splenic trauma – CVIR Endovascular

Patient selection

The study period was over 5-years from 1st January 2015 to 1st January 2021. All patients above the age of 16 undergoing SAE for blunt splenic trauma were identified through the radiology information system (RIS) and included into the study. Patients presenting with penetrating splenic injuries, undergoing isolated diagnostic splenic angiograms, or isolated DSAE, or PSAE for other reasons than blunt splenic trauma, were excluded. All patients included in the study underwent an initial pre-procedural contrast enhanced CT.

Data collection and definitions

Data was collected from RIS, picture archiving and communication system (PACS), and the electronic medical records (EMR). Information included demographics (age, gender), reported method of injury, initial CT information (date, time, findings, AAST splenic injury grade, solitary/multiple abdominal injuries), procedure information (date, time, type of embolic material utilized and location, complications, technical success), post-procedure progress (clinical success), complications (date, details), follow-up imaging (study type, date, findings, splenic perfusion).

Technical success was defined as significant blood flow reduction within the splenic artery at completion of the PSAE procedure. The demonstration of complete cessation of blood flow was not required. The development of collateral circulation was also utilised as a marker of significant blood flow reduction. Clinical success was defined as cessation of bleeding and spleen salvage after PSAE. This was deemed to be the case if the patient did not require reintervention and left the hospital with their spleen in situ or died from unrelated causes.

Definitions of splenic artery anatomy and embolisation types

We designed a classification system where the main splenic artery was divided into three segments based on the DPA and GPA origins. After review of images on PACS, patients were assigned to one of the three categories based on the location of their embolisation:

• Type I: when performed proximally to DPA or covering its origin.

• Type II: when performed between DPA and GPA, not covering their origins.

• Type III: when performed distally to GPA or covering its origin.

In this classification, Type II represents the ideal theorized location for embolisation, while Types I and III were the theorized locations to avoid (Fig. 2). When an anatomical variant was present, the same rules were applied. For example, if the DPA arose from the superior mesenteric artery, a Type I embolisation would not be possible as there would be no Type I location within the main splenic artery (Fig. 3).

Types of PSAE. a Type I, AVP (white star) was deployed proximally to the DPA, note perfusion of the spleen via prominent LGA collateral circulation. b Type II, AVP (white star) inserted between DPA and GPA origin, spleen perfusion via collateral pancreatic circulation. c Type III, coiling (white star) distal to GPA, minimal splenic perfusion via AsTP

PSAE in patient presenting with blunt splenic trauma and variant splenic anatomy. a Pre-embolisation diagnostic angiogram revealed the DPA arising directly from the coeliac trunk along with the left hepatic artery (LHA). CT angiography showed the right hepatic artery origin from the superior mesenteric artery, and the left gastric artery arising from the coeliac trunk, not shown here. b Post-embolisation angiogram shows an AVP plug (white star) inserted distal to the GPA origin and splenic perfusion maintained via the AsTP collateral circulation. This case was thus considered a Type III embolisation

PSAE procedural technique

All procedures were performed by one of eight consultant interventional radiologists along with one of five interventional radiology fellows. The access was from the femoral artery, using either a 6-Fr 11 cm Radifocus™ introducer sheath (Terumo, Tokyo, Japan) or 6-Fr 35 cm Pinnacle® destination sheath (Terumo, Tokyo, Japan), a guiding 4-Fr or 5-Fr catheter (Cook Medical, Bloomington, USA) to selectively catheterize the celiac trunk and/or splenic artery, and when needed 2-Fr, 2.4-Fr, 2.7-Fr Progreat® microcatheters (Terumo, Tokyo, Japan). Embolic materials according to operator preference included 5-10 mm Amplatzer vascular plugs 4 (AVP 4) (St Jude Medical, Plymouth, USA), 5-14 mm pushable coils and detachable microcoils Concerto Helix (0.018″ Medtronic, Minnesota, USA), Ruby (0.018″ Penumbra, California, USA), POD (0.025″ Penumbra, California, USA), VortX (0.018″ or 0.035″ Boston scientific, Massachusetts, USA), and Gelfoam (Pfizer, Michigan, USA).

Review of outcomes

All procedural angiograms were retrospectively reviewed and assessed for arterial anatomy and location of embolic agents. Both pre and post embolisation angiograms were reviewed. Patients who were imaged post embolisation had these assessed for evidence of pancreatitis and splenic perfusion. Post procedural blood parameters and clinical notes were reviewed for evidence of pancreatitis. Splenic perfusion was defined as the presence of contrast enhancement of the spleen on CT angiogram or the presence of a measurable Doppler signal on ultrasound, identified in > 50% of the splenic parenchyma.

Statistical analysis

Statistical analysis was conducted using the Stata16 program. Two-sided p-value < 0.05 was chosen to indicate statistical significance, which was ascertained between groups using a chi-squared test.