D-dimer measurement is useful irrespective of time from the onset of acute aortic syndrome symptoms

Background: In acute aortic syndrome (AAS) screening, D-dimer is a well-established biomarker whose usefulness has been scarcely studied with respect to its measurement timing. We aimed to evaluate the effectiveness of D-dimer-based AAS screening focused on the time interval between AAS onset and D-dimer measurement.

Methods: We retrospectively analyzed consecutive patients diagnosed with AAS who visited our hospital between 2011 and 2021. For the primary analysis, we divided patients according to the quartiles of the time interval between AAS symptom onset and D-dimer measurement. D-dimer level ≥ 0.5 μg/mL and age-adjusted D-dimer ≥ [age (years) × 0.01] μg/mL (minimum of 0.5 μg/mL) were defined as positive. The primary endpoint was the comparative ability of D-dimer to detect AAS within and between each time quartile. In an exploratory secondary analysis, we reported patient and AAS characteristics in the subgroup of patients who underwent repeat D-dimer measurement within 48 h of the first D-dimer measure.

Results: The 273 AAS patients were divided into four groups based on quartiles of the time interval (Group 1, ≤1 h; Group 2, 1-2 h; Group 3, 2-5 h; and Group 4, >5 h). There were no significant differences in D-dimer levels or in the proportions with positive D-dimer (Group 1: 97%, Group 2: 96%, Group 3: 99%, Group 4: 99%; P = 0.76) or positive age-adjusted D-dimer (Group 1: 96%, Group 2: 90%, Group 3: 96%, Group 4: 97%; P = 0.32) between the groups. Of the 147 patients who had D-dimer re-measured, nine had negative D-dimer levels on either the primary or secondary measurement. Of these nine patients, eight had AAS with a thrombosed false lumen and one with a patent false lumen had a short length of dissection. In all nine patients, D-dimer levels remained low (maximum of 1.4 μg/mL).

Conclusion: D-dimer levels were elevated from the early stages of AAS. The clinical utility of D-dimer is not affected by the time interval from AAS onset to D-dimer measurement, but rather is influenced by AAS characteristics.