Impact of a negative D-dimer result on the initial assessment of acute aortic dissection.

BACKGROUND: D-dimer shows high sensitivity but low specificity for the diagnosis of acute aortic dissection (AAD). Previous reports indicated that negative D-dimer patients have shorter dissection length. However, whether patients with negative D-dimer results have a good prognosis is unknown. This study aimed to elucidate the clinical characteristics and implications of a negative D-dimer result on AAD diagnosis. METHODS: The study group comprised 126 patients (71 males, 55 females; mean age, 69 ±â€¯11 years) with AAD admitted to our hospital between April 2009 and March 2015. Blood samples on presentation were used for D-dimer measurement. Clinical characteristics and outcomes were assessed. RESULTS: Nine (7.1%) and 117 (92.9%) exhibited negative and positive D-dimer results, respectively. The negative group showed a significantly lower extension score and a higher platelet count than the positive group. Multivariate analysis demonstrated that platelet count (odds ratio, 1.31 (1.09-1.58), p = 0.003) and extension score (odds ratio, 0.56 (0.33-0.96), p = 0.03) were significantly related to a negative result. Notably, 44% of patients in the negative group had type A dissection and 33% underwent an emergency operation due to cardiac tamponade. CONCLUSION: We found that high platelet count and low extension score were independent factors related to a negative D-dimer result. Even if the length of the dissection is short, an emergency operation is necessary in some patients with a negative D-dimer result. Physicians should recognize that a negative D-dimer result alone cannot exclude patients with fatal AAD conditions.

Usefulness of triphasic CT aortic angiography in acute and surveillance: Our experience in the assessment of acute aortic dissection and endoleak.

INTRODUCTION: Computed tomography angiography (CTA) has been widely used in the diagnostic evaluation of many aortic diseases, but no standardized techniques actually exist for aortic CTA. The aim of this study was to describe the usefulness of triphasic CTA in aortic assessment in both non-traumatic emergency and surveillance conditions. METHODS: We performed non ECG-gated CTA examinations with a 64-slice CT scanner using a triphasic protocol consisting of an unenhanced acquisition, and two (early and delayed) contrastographic phases with a delay of 25-30 s and 100-120 s respectively after the injection of contrast medium. Were retrospectively selected adult patients with imaging findings of acute aortic dissection (AAD) or endoleak (EL) from November 2012 to November 2014. RESULTS: AAD was detected in 36 (67%) patients: 23 type A-AADs, and 13 type B-AADs. The presence of EL was observed in 18 (33%) patients: 1 type Ia, 5 types IIa, 2 types IIb, 1 type IIIa and 9 types IIIb. DISCUSSION: Triphasic CTA is useful to provide correct and prompt diagnosis of AAD in emergency, allowing the evaluation of type and atypical forms of AAD, and the identification of possible branch-vessel involvement and complications. During surveillance, triphasic CTA assures accurate and complete assessment of all known and unknown ELs and it is essential for first follow-up examination. CONCLUSION: Triphasic CTA represents a reliable imaging tool for aortic assessment in both non-traumatic emergency and surveillance after endovascular aneurysm repair. Modified protocol could be employed in selected patients and tailored in their known disease.