Distal Splenic Artery Hemodynamic Changes During Transient Proximal Splenic Artery Occlusion in Blunt Splenic Injury Patients: A Mechanism of Delayed Splenic Hemorrhage

Background: Delayed splenic hemorrhage after proximal splenic artery embolotherapy (SAE) in patients with blunt splenic injury is a well-known outcome. The hemorrhage is thought to be due to rupture of a splenic parenchymal pseudoaneurysm. This study attempts to explain at least part of the mechanism involved in the delayed hemorrhage event. Methods: Hemodynamically stable patients with blunt splenic injury, without active extravasation, who underwent splenic artery angiography, also had the distal splenic artery pressure determined with transient balloon occlusion of the proximal splenic artery. Results: Seven patients were referred for splenic artery angiography. The average mean aortic pressure was found to be 89.0 +/- 21.9 mm Hg. The average mean distal splenic arterial pressure with temporary proximal occlusion was 47.1 +/- 25.8 mm Hg (range = 25-98 mm Hg). The average mean pressure drop was 41.9 +/- 19.0 mm Hg or 48.0 +/- 19.3%. The average systolic pressure drop was 75.4 +/- 24.0 mm Hg (range = 40-113 mm Hg). However, one of our seven patients only had a 14.8% mean arterial pressure drop and maintained a 102 mm Hg systolic pressure in the distal splenic artery. Conclusions: The arterial pressure in the distal splenic artery after SAE is highly variable and may depend on the robustness of pre-SAE collaterals.