Serum C-reactive protein elevation predicts poor clinical outcome in patients with distal type acute aortic dissection: Association with the occurrence of oxygenation impairment

Background: Acute aortic dissection (AAD) is sometimes complicated by respiratory failure due to severe lung oxygenation impairment. Systemic activation of inflammatory system after aortic injury may play some roles in the development of this complication. The aim of this study was to determine the significance of serum C-reactive protein (CRP) elevation in the development of oxygenation impairment and clinical outcome with distal type AAD. Methods and results: A total of 61 patients, who were admitted with distal type AAD within 24 h from the onset, were examined. Serum CRP levels, white blood cell (WBC) counts and body temperature were measured serially for at least 4 days. Oxygenation impairment, defined as the lowest PaO₂/FIO₂ ratio ≤200 mmHg, was noted in 31 patients (51%). In patients with oxygenation impairment, peak CRP levels (20.7±7.9 vs. 12.7±3.8 mg/dl, P<0.001), peak WBC counts (14,600±3600 vs. 11,800±4300/mm ³, P=0.008) and body temperature (38.4±0.5 vs. 38.0±0.6 °C, P=0.004) were significantly higher than those without. Peak CRP level was inversely correlated with the lowest PaO₂/FIO₂ (P<0.001). Patients who underwent urgent surgical treatment and/or died in the hospital had higher peak CRP levels (25.1±12.3 vs. 16.1±7.4 mg/dl, P=0.010) than those who did not. Multivariate analysis revealed that a peak CRP level ≥15 mg/dl (relative risk=12.6, P<0.001) was an independent determinant of the development of oxygenation impairment. Conclusion: The greater serum CRP elevation after distal type AAD was associated with a higher incidence of oxygenation impairment and poor clinical outcome. Systemic activation of the inflammatory system after aortic injury may play an important role in the development of oxygenation impairment.