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. Researchers will also study hospital length of stay and death after surgery.

This study is designed to help researchers understand whether a short, practical exercise test can improve the way surgical risk is assessed before an operation. Current preoperative assessment tools do not always measure how well the heart, lungs, and muscles work together during physical stress. smCPET may provide a more objective way to measure functional capacity and physiologic reserve in a busy clinic setting.

This is a single-center study based in a preoperative evaluation clinic. The study has a prospective observational cohort component and a retrospective validation component. In the prospective part, adults who meet clinic criteria and complete smCPET during routine care may be asked to join the repository. In the retrospective part, researchers may also review historical data from patients evaluated before smCPET was put into routine use to help compare outcomes and validate findings.

Because this is an observational repository study, participation does not change the care participants receive. The exercise test is done for clinical reasons, not because of the research study. The research team will not assign treatments or decide what surgery a participant has. Instead, the team will study how exercise test findings relate to outcomes that occur after surgery.

The long-term aim of this study is to improve preoperative risk assessment and help clinicians better identify patients who may need closer monitoring, more evaluation, or more support around the time of surgery. If the findings are useful, they may support broader use of brief preoperative exercise testing in adults having higher-risk noncardiac surgery.