Splenic Embolization in Nontraumatized Patients

Indications

Splenic artery embolization in the nontrauma setting has been advocated for a number of indications, including treatment of hypersplenism, sinistral portal hypertension, nontraumatic splenic rupture, splenic artery aneurysms, pseudoaneurysms and arteriovenous fistulae and splenic steal syndrome following liver transplantation. Each of these will be addressed in greater detail later within this chapter. First, we will review the technical aspects and principles of SAE in the nontrauma patient.

Anatomy

A thorough knowledge of the anatomy of the splenic artery and its branches is a prerequisite to performing splenic interventions effectively and safely. A working knowledge of the sites of origin and variations of the dorsal pancreatic, arteria pancreatica magna, left gastroepiploic, and short gastric arteries is important in maximizing the success of splenic embolization and minimizing potential complications. Other rare variants such as an accessory left colic artery arising from a terminal branch of the splenic artery and supplying an area of the splenic flexure can lead to nontarget embolization, if overlooked.

Contraindications

Apart from the usual contraindications of any angiographic procedure there are no specific absolute contraindications for SAE. In patients with splenomegaly who are undergoing distal splenic artery embolization, care should be taken to reduce the severity of postembolization syndrome by performing a number of sequential partial embolization procedures rather than embolizing a large area of spleen in one sitting.

Preprocedure Work-Up

Review of any preprocedure cross-sectional imaging should be performed to determine the course and any anatomical variations of the coeliac axis or its branches, which may influence the selection of the site of arterial access.

In patients who are likely to become functionally hyposplenic or asplenic, consideration should be given to whether a pneumococcal vaccine needs to be administered to mitigate against the risk of pneumococcal sepsis. The lifetime risk of overwhelming postsplenectomy sepsis is 5% and carries a mortality of up to 70%. Pneumococcal vaccination is therefore common practice in patients having splenectomy, although there is no consensus on whether or not it is indicated in patients undergoing SAE. Most practitioners recommend the use of preprocedure broad-spectrum antibiotics; exact protocols are up to local departmental guidelines. If there is a likelihood of splenic infarction, the patient should be prescribed adequate analgesia, ideally delivered via a patient-controlled analgesia pump.

Procedural Technique and Equipment

The procedure can be performed from a femoral or upper limb (brachial/radial) access, according to the anatomy of the coeliac axis and splenic artery and the preference of the operator. After placement of an appropriately sized sheath, selective coeliac axis and splenic artery angiography is performed using a catheter of the operator’s choice, commonly a Cobra or Sidewinder catheter without side holes. Catheterization of the more distal splenic artery will generally require the use of a coaxial microcatheter, due to the tortuous nature of the splenic artery. The initial angiogram provides a roadmap of the splenic artery, its main branches, and any important anatomical variants.