Comparisons of potential values of D-dimer and the neutrophil-to-lymphocyte ratio in patients with suspected acute aortic syndrome

Objectives: This study aimed to investigate and compare the discriminative performance and clinical utility of D-dimer and the neutrophil-to-lymphocyte ratio (NLR) in the early differential diagnosis of acute aortic syndrome (AAS). Methods: The consecutive patients presenting to Tianjin Chest Hospital for suspected AAS were retrospectively investigated between June 2018 and December 2021. The baseline values of D-dimer and NLR were analyzed and compared in the study population. The discriminative ability of D-dimer and NLR was illustrated and compared using the area under the receiver operating characteristic (ROC) curve (AUC), net reclassification improvement (NRI) and integrated discrimination improvement (IDI). Clinical utility was evaluated by means of decision curve analysis (DCA). Results: In the study period, a total of 697 participants suspected of having AAS were enrolled and 323 had a final diagnosis of AAS. The baseline level of NLR as well as D-dimer was higher in patients with AAS. The use of NLR showed excellent overall diagnostic performance for AAS with a comparable AUC to that of D-dimer (0.845 vs. 0.822, P > 0.05). The reclassification analyses further confirmed that NLR had better discriminative properties for AAS with a significant NRI of 66.1% and IDI of 12.4% (P < 0.001). Moreover, NLR provided higher net benefit than D-dimer as shown by DCA. Similar results were observed in subgroup analyses according to the different classes of AAS. Conclusions: NLR outperformed D-dimer with improved discriminative performance and superior clinical utility in identifying AAS. As a more readily available biomarker, NLR maybe a reliable alternative to D-dimer for the screening of suspected AAS in clinical practice.