From January 2017 to February 2020, patients presenting with SAA and treated by detachable coil embolization with moderate density packing were retrospectively analyzed and inserted into standardized piloted forms. This retrospective study aimed to evaluate the efficacy of the coil embolization technique in the treatment of true SAAs on an intention-to-treat basis using a coil moderate density packing. Splenectomy was not performed as a routine intervention associated with SAA coil embolization. Indications to SAA repair were a transverse diameter > 2 cm, pseudoaneurysm at any size, and/or women in childbearing age at any size or abdominal symptoms. Ruptured SAAs were excluded from the study. All patients were considered not anatomically candidate to SAA exclusion using stent-graft.
The study was performed in agreement with the Declaration of Helsinki and STROBE guidelines for reporting observational studies were followed.[6] All patients gave informed consent for the procedure itself, anonymous data collection, and analysis. The study was approved by the local institutional review board, according to the National Policy in the matter of Privacy Act on retrospective analysis of anonymized data. The retrospective and anonymized nature of the study did not require medical ethical committee approval.
Demographics, comorbidities, medical treatment, clinical presentation, and procedural data were collected. The preoperative assessment consisted of computed tomography angiography (CTA) and splenic duplex ultrasound (DUS) in all cases (Fig. 1). Baseline laboratory investigations including complete white blood count, liver function tests, renal function test, and LDH were collected in all cases. SAA categorization was as proximal, median, or parailar according to its location.
Embolization procedure. SAA embolization procedures were planned on preoperative CTA. The more appropriate route to the target lesion was selected according to the condition of remote access and the vessel employed to reach the SAA. The angle of the origin of the celiac trunk (CT) and the aorta was another determinant for the route to the target lesion.
The procedures were carried in a dedicated angiosuite equipped with a fixed radioscopy system (GE Innova 4100 Cath Angio System; General Electric Medical Systems, EU) in a standard fashion. The patient was positioned onto the angiographic table and draped. Vascular access was gained under local anaesthesia and DUS guidance through the common femoral artery (CFA) or the brachial access (left or right) according to the planned procedure.
An introducer sheath was inserted via the vascular access and administered 2500 IU of heparin. The origin of the CT and subsequently the splenic artery were engaged using a 5F C2 or Simmons catheter. Subsequently a 5F Flexor sheath (Cook Medical, Bloomington, IN, US) introducer was advanced until the CT origin; a 45 cm length or a 90 cm introducer length was employed for the femoral or the brachial access respectively. Multiplanar pre-procedural arteriograms were performed to determine the SAA characteristics and confirm CTA findings.
The SAA was cannulated using a .018 wire (Command; Abbott Vascular, Santa Clara, CA, US) or a .014 wire (Balance Middle Weight -BMW, Abbott Vascular), and a Rebar 18 microcatheter (EV3, Irvine, CA, US) was positioned into the SAA. At this stage, the Concerto Helix Detachable Coil System PGLA-fibered (Medtronic, Inc., Minneapolis, MN, US) was deployed inside the SAA until the aneurysm sac completely felling (Fig. 2). Coils number and dimension depended on the size of the aneurysm; as general principle larger and longer coils were employed at the filling beginning; smaller coils were employed to achieve a moderate SAA packing.
The coil filling ended once a reduced contrast media caption into the SAA was evident in association to a 15–20% moderate volume coil packing (Fig. 3).
SAA luminal volumes was calculated using the images from the preoperative CTA imported into the Horos software (LGPL 3.0; GNU Lesser General Public License). The SAA was manually segmented using at least 3 ROI measurements for luminal volume calculation. The luminal volume was defined as the volume free of thrombus within the aneurysm sac.
As an example, for a 35 mm SAA maximal transverse diameter, presenting a luminal aneurysm volume of 33.229 mm3, to achieve a 15–20% of coil packing density, a 14mmx30cm Concerto coil (Coil volume of 6.594 mm3) is employed.
After the procedure, the administered heparin was not reversed and a single prophylactic low molecular weight heparin (LMWH) shot was administered after 6 hours from the index procedure to reduce the risk of deep venous thrombosis. Therapy with single or double antiplatelet agent and/or LMWH was not discontinued during the SAA coil embolization. Anticoagulants were switched to LMWH before intervention.
Outcomes. Technical success, early (within 30 days), and late (after 30 days) results were the measured outcomes. Technical success was defined as intraoperative SAA exclusion.
Early and late outcomes included mortality, morbidity, abdominal symptoms onset, and splenic infarction on DUS.
Follow-up consisted of clinical examination, laboratory tests, and splenic DUS on 1st postoperative day; laboratory test at 14th POD; DUS and laboratory test at 1 month; laboratory test and basal CT at 2 months (Fig. 4); laboratory test and DUS at 6 months. Median follow-up was 34.77 ± 9 (mean: 25.49; IQR: 9–38) months.
Statistical analysis. Parametric data are presented as the mean and interquartile range (IQR) or median and min-max range; absolute values and percentages for non-parametric data. Differences in preoperative and postoperative outcomes were assessed using the Student t test. Statistical significance was considered at P < .05. Statistical analysis was performed using SPSS 16.0 (SPSS Inc., Chicago, IL, USA).