Figure 1:

Workflow for the study. Aortic tissue was obtained during aortic replacement surgery or from post-mortem tissue for control (n = 13) or aneurysm patients (n = 44). Rapid evaporative ionization mass spectrometry data were acquired over 2 days with samples measured on both days (where sufficient tissue was available) to test intra- and inter-sample reproducibility (see Supplementary Material, Fig. S1). A merged dataset was produced with ∼50% of samples from each rapid evaporative ionization mass spectrometry dataset. Partial least squares-discriminant analysis modelling was performed and tested using randomly generated training (80%) and test (20%) data (round 1). Important features of the models were extracted (variable importance of projections) and variables selected from these for further modelling (round 2). Models from round 2 showed increased accuracy and precision.