Abstract 252: Negative D-dimer Test for Acute Aortic Dissection

Abstract

OBJECTIVE: Recent studies have indicated the effectiveness of D-dimer values as a negative predictor to rule out a diagnosis of acute aortic dissection (AAD) in patients with chest pain. In contrast, there are several other studies suggesting D-dimer levels are not always elevated in dissecting patients in emergency settings. The aim of the present study is to identify the independent predictors relating to negative results of D-dimer testing for AAD. METHODS: Single center prospective observational study was performed for 5 years in an emergency department of a university hospital in Tokyo. Consecutive 49 patients with AAD (32 males, median age: 63 y/o) were enrolled in this study. Diagnosis of AAD was confirmed by enhanced computed tomography (CT) in all patients. Of those, 18 patients presented Stanford type A and 22 patients had thrombosed false lumen. Venous blood was drawn soon after patients' arrival (all performed within 24 hrs from symptom onset, median time: 50 min), and WBC, CRP, and D-dimer levels were obtained. Dissection lengths were measured using CT by another physician in a blinded fashion. Univariate anlyses were performed by t-test or chi-square test where appropriate, and a Logistic regression analysis was used as a multivariate analysis. RESULTS: Medain (IQR) of plasma D-dimer levels of a consecutive series of 49 patients were 7.8 (0.3 to 113.8) μg/ml. Of the 49 patients, 5 (10.2%) showed negative D-dimer test results (< 0.5μg/ml). Although age, sex, Stanford types, false lumen conditions, WBC, and CRP levels in these 5 patients were similar to those in other 44 patients with positive results, dissection length was significantly shorter in 5 negative results patients (132±119 vs 314±147 mm in positive results patients, P=0.01). The Logistic regression analysis using a backward elimination model revealed age and dissection length were identified as independent predictors for a negative D-dimer test result (Odds ratio and [95% CI]: 0.89 [0.79 to 0.99], 0.98 [0.96 to 0.99], respectively). CONCLUSION: In the present patient registry, 10% of patients with acute aortic dissection in emergency settings showed negative D-dimer test results. The negative D-dimer results were related to younger age and shorter dissection length.