BACKGROUND AND OBJECTIVES: Systemic activation of the inflammatory system after aortic injury may play a role in the development of complications. The aim of this study was to determine the significance of the inflammatory markers for the mortality of patients suffering with medically treated type B acute aortic syndrome (AAS). SUBJECTS AND METHODS: We analyzed a total of 81 patients who were admitted with AAS within 24 hours from the onset of the symptoms and who were medically treated between January 2000 and December 2004. The patients were divided into two groups: the moribund patients who died within 2 weeks (group I: n=8, mean age: 64.0+/-11.0 years) and the patients who survived over 2 weeks (group II: n=73, mean age: 62.6+/-13.7 years). The serum high-sensitivity C-reactive protein (hsCRP) levels, the white blood cell (WBC) and monocyte counts, and the plasma D-dimer levels were measured on admission. RESULTS: The baseline clinical characteristics were not different between the two groups. The major causes of in-hospital death in group I were extensions or rupture of type B dissection (6 cases) and acute renal failure (2 cases). The multivariate analysis demonstrated that a high monocyte count (>1,250/mm3), and high levels of hsCRP (>11 mg/dL) and D-dimer (>1.2 mg/dL) were independent determinants of the short-term mortality (OR=6.39, 6.14 and 9.00; 95% CI=1.19 to 34.1, 1.14 to 32.9 and 1.20 to 67.4; p=0.02, 0.04 and 0.03, respectively). CONCLUSION: Systemic activation of the inflammatory system in type B AAS patients may be one of the important factors associated with the development of short-term mortality.