Preoperative Exercise Testing and Perioperative Outcomes

The goal of this observational study is to learn whether results from a brief exercise test done before surgery can help identify adults who may be more likely to have problems after moderate- to high-risk noncardiac surgery. The study includes adults older than 45 years who are seen in a pre-surgical evaluation clinic and complete submaximal cardiopulmonary exercise testing, or smCPET, as part of their usual clinical care. The main questions it aims to answer are: Are smCPET measurements linked with early problems after surgery? Are smCPET measurements linked with later problems after surgery, including complications within 30 and 60 days, longer hospital stay, and death? Can smCPET add useful information to standard preoperative risk assessment? Researchers will observe and analyze information collected during routine care. No extra exercise testing or treatment will be done for research. Participants will: * Complete routine preoperative evaluation in the Yale Pre-Surgical Evaluation Clinic. * Undergo smCPET if it is ordered as part of standard clinical care. * Allow researchers to collect information from the medical record and from the exercise test for the study repository, if they agree to participate. The study will collect de-identified information about each participant's health before surgery, exercise test results, details about the surgery and hospital stay, and problems that happen after surgery. This may include age, sex, body mass index, other medical conditions, routine lab and imaging results, heart rate, blood pressure, oxygen levels, smCPET measures such as peak oxygen uptake, anaerobic threshold, and breathing efficiency, and early and late postoperative outcomes. Researchers will look at short-term and later outcomes after surgery. These include problems identified during the hospital stay, such as heart, lung, kidney, nerve, blood, wound, and pain-related complications, as well as complications within 30 and 60 days after surgery. Researc