Segmental Arterial Mediolysis: A Systematic Review of Clinical Presentations, Management and Outcomes

To consolidate evidence on the clinical profile of segmental arterial mediolysis (SAM), and to identify independent predictors of unfavourable outcomes and mortality.

PubMed/MEDLINE was systematically searched for SAM reports with patient-level data. Data analysis used chi-square/Fisher's exact, Mann-Whitney, Kruskal-Wallis tests, and multivariable logistic regression, with sensitivity analyses across three subgroups.

230 confirmed cases of SAM were included (mean age 54.5 years; 65% male). Hypertension was the most common comorbidity (21.7%). Most patients (84%) presented acutely, typically with abdominal pain (49%) or hemorrhage (19.6%). Multifocal involvement frequently involved the superior mesenteric (40%), hepatic (40%), and celiac arteries (36.5%). Imaging was dominated by aneurysms (69-100%) and dissections (0-65%). Elevated ESR/CRP was associated with organ ischemia (OR 3.36, 95% CI 1.65-6.86, p=0.002). Management was guided by clinical stability and lesion morphology, with medical therapy and transarterial embolization being the most common. Overall, 81.3% achieved favorable outcomes; 18.7% had progression or death. Overall mortality was 9.1%. Neurological territory involvement (OR 7.25, 95% CI 2.61-20.14, p<0.001) and organ ischemia on imaging (OR 2.56, 95% CI 1.07-6.10, p=0.034) were independent predictors of unfavorable outcome. Neurological involvement (OR 5.73, 95% CI 1.71-19.15, p=0.005) and female sex (OR 3.88, 95% CI 1.38-10.88, p=0.010) were independent predictors of mortality. Findings were robust on sensitivity analyses.

SAM typically presents with multifocal mesenteric/hepatic aneurysms or dissections and favorable outcomes with conservative or endovascular management. Neurological involvement and organ ischemia predict worse outcomes, supporting risk-stratified management and surveillance.