Can preoperative neutrophil-to-lymphocyte ratio predict in-hospital mortality in postoperative patients with Stanford type A aortic dissection? Evidence-based appraisal by meta-analysis and GRADE.

objectivesIn-hospital mortality in postoperative patients with type A aortic dissection (AAD) is high. Neutrophil-to-lymphocyte ratio (NLR) is a novel predictor of adverse outcomes in many cardiovascular diseases. We examine NLR as a predictive tool in AAD in this meta-analysis. MATERIALS AND

methodsWe systematically searched in four databanks. Risk of bias was appraised using the Quality Assessment of Diagnostic Accuracy Studies 2 tool. The midas and metandi commands in Stata 15 were used for the meta-analysis. The certainty of evidence was assessed by the Grading of Recommendations, Assessment, Development, and Evaluation methodology (GRADE).

resultsFour studies with 502 cases in total were included. Pooled sensitivity and specificity were 0.71 (95% confidence interval [CI] = 0.52-0.79) and 0.64 (95% CI = 0.55-0.71), respectively. Area under the hierarchical summary receiver operating characteristic curve yielded 0.73 (95% CI = 0.68-0.76). The diagnostic odds ratio was 4.42 (95% CI = 2.56-7.62). Pooled positive and negative likelihood ratios yielded 1.98 (95% CI = 1.53-2.55) and 0.45 (95% CI = 0.32-0.62), respectively. When the pretest probabilities were 25%, 50%, and 75%, the positive posttest probabilities were 40%, 66%, and 86%, and the negative posttest probabilities were 13%, 31%, and 57%, respectively, according to the Fagan's nomogram plot. The overall certainty of evidence in GRADE was low and very low in sensitivity and specificity, respectively.

conclusionThe pooled diagnostic values of preoperative NLR, an inexpensive and routine laboratory examination, provide a practicable help for predicting in-hospital mortality for patients with postoperative AAD in our meta-analysis.