Imaging and clinical findings in segmental arterial mediolysis (SAM)

Abstract

Segmental arterial mediolysis (SAM) is an uncommon, non-atherosclerotic, non-inflammatory arteriopathy that tends to affect the medium-sized splanchnic branches of the aorta along with renal, carotid, cerebral, and coronary arteries. The clinical presentation ranges from asymptomatic to severe, life-threatening intra-abdominal hemorrhage and shock. SAM overlaps clinically and radiologically with other inflammatory vasculitides. This article describes the pathologic-radiologic correlation, imaging findings, and the management of the disease. Radiologists should be familiar with this disease entity as imaging plays a crucial role in the diagnosis.

Spontaneous Recovery of Multiple Hepatic Artery Aneurysms with Segmental Arterial Mediolysis

“…To the best of our knowledge, only four cases of SAM involving the intrahepatic arteries have been previously reported [3,5,7,9]. As the occurrence of SAM in the intrahepatic artery is extremely rare, physicians would likely not consider SAM when assessing patients with hepatic artery aneurysm.…”

“…For example, the first reported patient with SAM died because of hemorrhagic shock [7]. Of the three remaining patients, two underwent coil embolization for bleeding from the aneurysm and painful symptoms, or rupture of the aneurysm with fistulous connection to the portal vein [3,9]. In contrast, Tomonaga et al reported a patient with ruptured SAM who successfully underwent conservative treatment [5].…”

“…There is no standardized treatment strategy for SAM. There are several treatment options: surgery; endovascular treatments, such as transcatheter arterial embolization (TAE), angioplasty, and stent placement; and conservative treatment [1,3,4]. TAE is indicated if active bleeding due to rupture of the aneurysm occurs [1,3].…”

“…There are several treatment options: surgery; endovascular treatments, such as transcatheter arterial embolization (TAE), angioplasty, and stent placement; and conservative treatment [1,3,4]. TAE is indicated if active bleeding due to rupture of the aneurysm occurs [1,3]. However, TAE in patients with stable hemodynamic status should be carefully considered because new arterial wall dissection and aneurysm rupture may be caused by catheter manipulation [1].…”

“…Segmental arterial mediolysis (SAM) is characterized by multiple aneurysmal dilatations and stenosis induced by idiopathic dissections, and it can potentially cause spontaneous hemorrhage [1,2]. SAM is also known as the one-shot disease because it sometimes results in spontaneous recovery; however, it can be fatal, and interventional or surgical treatment is required if rupture occurs [1,[3][4][5]. Therefore, the treatment strategy for SAM remains controversial.…”