 The Investigator postulate that the use of PESI in addition to routine clinical practice, as opposed to routine clinical practice based on clinical judgment alone, will help physicians to correctly identify PE patients at low-risk of adverse outcomes. Considered that low-risk patients could benefit from a short hospital stay, aim of this study is to demonstrate that the use of PESI will lead physicians to discharge these patients earlier, thus reducing the duration of hospital stay of PE patients primary outcome. 