Tuyển tập các báo cáo nghiên cứu về y học được đăng trên tạp chí y học Wertheim cung cấp cho các bạn kiến thức về ngành y đề tài: Long-term mortality prediction after operations for type A ascending aortic dissection. | Macrina et al. Journal of Cardiothoracic Surgery 2010 5 42 http content 5 1 42 Jdfrs JOURNAL OF CARDIOTHORACIC SURGERY RESEARCH ARTICLE Open Access Long-term mortality prediction after operations for type A ascending aortic dissection Francesco Macrina31 Paolo E Puddu 32 Alfonso Sciangula23 Marco Totaro1 2 Fausto Trigilia1 Mauro Cassese3 and Michele Toscano1 Abstract Background There are few long-term mortality prediction studies after acute aortic dissection AAD Type A and none were performed using new models such as neural networks NN or support vector machines SVM which may show a higher discriminatory potency than standard multivariable models. Methods We used 32 risk factors identified by Literature search and previously assessed in short-term outcome investigations. Models were trained 50 and validated 50 on 2 random samples from a consecutive 235-patient cohort. NN were run only on patients with complete data for all included variables N 211 SVM on the overall group. Discrimination was assessed by receiver operating characteristic area under the curve AUC and Gini s coefficients along with classification performance. Results There were 84 deaths 36 occurring at 564 48 days 95 CI from 470 to 658 days . Patients with complete variables had a slightly lower death rate 60 of 211 28 . NN classified 44 of 60 73 dead patients and 147 of 151 97 long-term survivors using 5 covariates immediate post-operative chronic renal failure circulatory arrest time the type of surgery on ascending aorta plus hemi-arch extracorporeal circulation time and the presence of Marfan habitus. Global accuracies of training and validation NN were excellent with AUC respectively and but classification errors were high among patients who died. Training SVM using a larger number of covariates showed no false negative or false positive cases among 118 randomly selected patients error 0 AUC whereas validation SVM among 117 patients provided 5 false
