BackgroundInflammation plays an important role in the initiation and progression of acute aortic dissection (AAD). New inflammatory indices derived from full cell blood count and its differential may be associated with increased risk. We evaluated platelet‐lymphocyte (PLR), red cell distribution width (RDW) and RDW/PLT's (platelets) (RPR) in AAD.MethodsWe studied 120 consecutive patients with AAD type I admitted for emergency surgery (group I), 121 consecutive patients with aortic aneurysms of the ascending aorta prior to elective repair (group II) and 121 controls (group III), age and sex matched.ResultsPLR was significantly higher in group I vs both groups II and III (P < .001). There was an excellent correlation of PLR with neutrophil/lymphocyte ratio (NLR) in all three groups (P < .001 for all). After adjustment for hemoglobin, RDW did not differ but RPR remained significantly higher in group I compared to groups II and III (P < .001). The best cutoff value of PLR to predict dissection was 159 with 53% sensitivity and 86% specificity. No association between PLR, RDW, and RPR and mortality in group I was found.ConclusionsIndices derived from full cell blood count may provide diagnostic information in patients with AAD; whether these indices may contribute to prognosis assessment should be further investigated.