Segmental arterial mediolysis (SAM): Systematic review and analysis of 143 cases

Abstract

Segmental arterial mediolysis (SAM) is a rare but serious nonatherosclerotic, noninflammatory vasculopathy of unknown etiology that often results in dissection, aneurysm, occlusion, or stenosis of, primarily, the abdominal arteries. Current literature lacks consensus on diagnostic criteria and management options for SAM. This review summarizes 143 cases and aims to advance appropriate recognition and management of SAM. Literature review of all relevant SAM case studies from 2005 to 2018 yielded 126 individual SAM cases from 66 reports. We identified 17 additional SAM cases from our center, bringing our analysis to 143 patients. Patients with SAM were most commonly men (68%) in their 60s. Hypertension (43%), tobacco use (12%), and hyperlipidemia (12%) were common comorbidities. Abdominal pain (80%) and intraabdominal bleeding (50%) were the most common presenting symptoms. Computed tomography was the most frequently used imaging method (78%), and histology was available in 44% of cases. The most commonly affected vessels were the superior mesenteric (53%), hepatic (45%), celiac (36%), renal (26%), and splenic (25%) arteries with aneurysm (76%), dissection (61%), and arterial rupture (46%). Treatments included coil embolization (28%), abdominal organ surgery (24%), open arterial repair (21%), and medical management (20%). Case-specific treatment modalities yielded symptom relief in the vast majority (91%) of patients, with a mortality rate of 7%.

Rapid Formation and Rupture of Multiple Abdominal Pseudoaneurysms: A Life Threatening Case of Segmental Arterial Mediolysis

“…3) Although there are no proven risk factors, hypertension is commonly associated with SAM in the literature. 2) There are currently no known precipitating factors for an acute episode of the disease and patients typically present with sudden abdominal pain secondary to dissection, ischaemia or haemorrhage. 2,4) SAM poses a diagnostic challenge as clinical presentations can vary from a brief episode of abdominal pain with stable disease to significant haemodynamic instability from haemorrhage.…”

“…2) There are currently no known precipitating factors for an acute episode of the disease and patients typically present with sudden abdominal pain secondary to dissection, ischaemia or haemorrhage. 2,4) SAM poses a diagnostic challenge as clinical presentations can vary from a brief episode of abdominal pain with stable disease to significant haemodynamic instability from haemorrhage. As such, the natural history of SAM is poorly understood and the estimated mortality rate of SAM varies from 0 to 60%.…”

“…As such, the natural history of SAM is poorly understood and the estimated mortality rate of SAM varies from 0 to 60%. 2,5,6) Diagnosis of SAM may not require histopathological confirmation, as CT findings of arterial dissection, fusiform aneurysms, wall thickening and string of beads appearance affecting abdominal visceral arteries are often sufficient for diagnosis. 2) Kalva et al described a noninvasive diagnostic criteria for SAM.…”

“…1) SAM most commonly affects coeliac, mesenteric and renal arteries, and its presentation varies from chronic mesenteric ischaemia to acute life-threatening haemorrhage thus posing both a diagnostic and therapeutic challenge. 1,2) We report a case of SAM in a 62-year-old gentleman presenting with rapid formation and rupture of pseudoaneurysms who was successfully treated with early coil embolisation.…”

Aneurysms and dissections - What is new in the literature of 2019/2020 - a European Society of Vascular Medicine annual review

“…Current literature lacks consensus on diagnostic criteria and management options for SAM. The review of Sheik et al summarises 143 cases and aims to advance appropriate recognition and management of SAM [30]. Pts with SAM were most commonly men (68%) in their 60 s. Abdominal pain (80%) and intraabdominal bleeding (50%) were the most common presenting symptoms.…”