To our knowledge, this is the first meta-analysis to explore the relationship between D-dimer and in-hospital mortality of acute aortic dissection. After pooling the relevant studies, a link between D-dimer and in-hospital mortality was found. Much more than this, the predicted value was more significant with higher D-dimer. It may be an effective predictive biomarker for clinicians to identify patients at high risk of death.
As we know, the role of D-dimer used as an initial diagnosis marker was widely studied [11–13]. However, the evidence of predicting role of D-dimer for AAD in-hospital mortality is not only scarce but controversial[14–15]. In 2006, Weber et al. found that absolute D-dimer concentrations can forecast in-hospital mortality of type A AAD patients independently [OR and 95%CI: 1.32(1.01–1.75)]. A similar relationship was observed in the study conducted by Ohlmann et al. They found that D-dimer may reach a high level of above 20ug/mL in some AAD patients three hours after the symptoms onset, and the concentration was high in dead than survival patients . In the present meta-analysis, we combined all the eligible studies together and confirmed the link between D-dimer and in-hospital mortality of AAD. What’s more, we found a stronger predictive power with higher D-dimer cutoff value.
The mechanism that D-dimer can predicted mortality of AAD remains unclear. According to previous researches, dissection anatomical extent was assumed to associate with the amount of coagulation and fibrinolytic activation. Tissue factor of dissected aorta triggered coagulation cascade, the activation of extrinsic pathway can be counteracted by endogenous fibrinolytic activity. While, the serum D-dimer, as the degradation product of cross-linked fibrin, may rise due to endogenous fibrinolytic activity . An increased plasma D-dimer may be a manifestation of severe anatomical degree of dissection and greater mortality. D-dimer might be high when ascending aorta is involved for reflecting the higher frequency of unfavorable outcomes. According to our study, the association was obvious and stable in type A AAD. It is better to separate the type of AAD when using D-dimer to predict the in-hospital mortality of AAD patients.
This meta-analysis had several strengths. Firstly, we included both case-control and prospective studies to clarify the relationship between D-dimer and in-hospital mortality of AAD. Secondly, a large number of participants and cases guaranteed the sufficient statistical power to draw the credible conclusions. Third, in the current meta-analysis, the covariate adjusted OR and 95% CI were extracted from each study, which increased the accuracy of the summary estimation. However, several limitations should also be considered. Firstly, the included studies were mainly conducted in China. Therefore, the finding might be limited to apply to other countries. Secondly, the included studies adjusted for different confounders might have influenced our results. Lastly, publication bias was found among studies.