Figure 4. Classification and Regression Tree Model.
Abbreviations: DLCO: Diffusing capacity for carbon monoxide; FVC: Forced vital capacity; LVEF: Left ventricular ejection fraction; PA: Pulmonary artery; RV: Right ventricular. At each split, an observation goes to the left branch if the condition for the variable is satisfied as illustrated in the Legend. There are 10 terminal nodes in the CART model with the sample sizes for the classification of each node denoted in parentheses. Of the training split of 90 patients, the residual mean deviance of the CART model was 0.65, and the misclassification error rate was 0.16.