The purpose of this study was to investigate the prognostic relationship between DLR and AAD. In order to decrease the heterogeneity of research objects, we focused the investigation on the early phase of the disease (within the first 48 hours after symptom onset).The key fingdings were that AD patients with high admission DLR level was a powerful predictor of in-hospital mortality after adjusting for confounding factors in this retrospective study in addition to high HR and PT. In comparison to patients with low level of DLR, patients with a value >907 had a relatively high preoperative WBC and NEUT count, PLR, NLR, PT, CR, LDH, D-dmier, low preoperative platelet and LYM count, FIB, TC, LDL, BNP. In addition, our results suggest that in-hospital and its importance increases progressively with higher HR and PT. To our knowledge, this is the first time that DLR has been investigated for its clinical utility in the evaluation of in-hospital mortality in patients with AAD.
A growing body of literature showed that inflammatory cells play an important role in development and progross of dissection of the aorta, such as WBC(21), CRP(22), neutrophil(23), platelet(24), and combination of neutrophil/platelet and lymphocyte(22, 25). Among inflamation indictors, immule infiltration of the aortic wall with lymphocyte has attracted researchers increasing attention as an independent prognostic factor of AD-related diseases in recent years(26). Most researches have been demonstrated that inflammatory cells such as lymphocytes are able to induce apoptosis of smooth muscle cells and synthesis of metalloproteases(27, 28). However, the exact mechanism by which lymphocytes influence the prognosis of arterial disease in detail, including AD, remains unclear. Studies found that Lymphopenia was associated with the progression of atherosclerosis(29), and low level of lymphocytes in peripheral blood may be caused by lymphocyte apoptosis in atherosclerotic lesions, which gradually increases with atherosclerotic burden(30). del Porto et al. have shown that T lymphocytes were poorly represented in the aortic media, and significant decrease in total T lymphocytes and T helper fractions was found in the peripheral blood of patients with AAD by flow cytometry(31). Soon afterwards Bedel et al. discribed that critical patients with lymphopenia, including AAD, had poor prognosis(16), which is consistent with the results presented here.
As a degradation product of cross-linked fibrin, D-dimer has become an important complementary tool in the diagnosis of thrombotic plasticity diseases, and has also been used in the diagnosis and prognosis of acute AD. A negative D-dimer result may be useful to help rule out acute AD with a sensitivity of 100%(32). Patients with D-dimer༜0.1 mg/mL will exclude AAD in all suspected cases(33). Consistent results were observed in several studies that elevated D-dimer levels were associated with early mortality and postoperative compliactions(34, 35). Admission D-dimer levels (>6.10 mg/ ml) were associated with an increased risk of in-hospital death(19). The D-dimer level in patients with AAD was influenced by dissection type. Based on types of AD, D-dimer concetration (≥20 mg/ml) can serve as a powerful indictor for increased in-hospital mortality in Stanford type A AD patients(36).
The present research did not find D-dimer or lymphocytes to be an independent prognostic factor on multivariate analysis. A significant negative association between D-dimer and lymphocytes was obversed. Simialr to this, we found that a significant positive relationship between DLR and D-dimer, but negative association between DLR and lymphocytes. Their values in predicting inhospital mortality risk for acute AD might be better interpreted when they were considered as a whole. This study, though, is the first to examine the relationship between DLR and prognosis. Some limitations existed in this study. First, this is a single-center, and small sample observational study. The present results may be affected by the regional characteristics of patients in our hospital, and caution needs to be taken in spreading the application of research findings. Second, the study was designed for focusing on the in-hospital mortality. The long-term clinical outcomes and complications should be equally observed. In addition, there is a lack of research on the mechanism of DLR affecting vascular disease. Hence, Further multicenter studies will be conducted to verify the current findings.
In conclusion, a high admission DLR level might be a powerful predictor for increased in-hospital mortality in patients with AD.