D-dimer for screening of aortic dissection in patients with ST-elevation myocardial infarction

Acute aortic dissection (AAD) with concurrent ST-segment elevation myocardial infarction (STEMI) is relatively rare and sometimes overlooked. As D-dimer testing has been reported to have high sensitivity to diagnose AAD in a clinical scale, Aortic Dissection Detection Risk Score (ADD-RS), a point-of-care D-dimer analyzer capable of measuring in 10 min would be useful to deny AAD with concurrent STEMI. However, an optimal cut-off value of D-dimer in such population remains unclear. Therefore, the aim of this study was to elucidate the optimal D-dimer threshold in patients clinically diagnosed with STEMI.

This retrospective cohort study was conducted at two tertiary care centers between 2014 and 2019. Patients clinically diagnosed with STEMI who underwent serum D-dimer measurement on hospital arrival were included. The primary outcome was the diagnosis of AAD. The area under the receiver operating characteristic curve (AUROC) for D-dimer values to diagnose AAD was evaluated, particularly in patients with low to moderate risks of AAD (1 of ADD-RS). The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated with several cut-off values.

A total of 322 patients were included, and 28 were diagnosed with AAD. The AUROC for D-dimer to diagnose AAD was 0.970 (95% confidence interval: 0.948-0.993) in 262 patients with 1 of ADD-RS. If D-dimer ≥750 ng/mL was used as a cut-off value, sensitivity, specificity, PPV and NPV were 100%, 86.4%, 37.7%, and 100%, respectively. AAD could be denied in 209 (79.8%) patients using the cut-off value (D-dimer <750 ng/mL).

Serum D-dimer ≥750 ng/mL exhibited high sensitivity and NPV to diagnose AAD with concurrent STEMI, while the ADD-RS originally utilized ≥500 ng/mL as a cut-off for any suspected AAD. A point-of-care D-dimer measurement with the new cut-off would be useful to rule-out AAD among patients with STEMI.