The objective of this prospective observational cohort study is to evaluate the validity, reliability, and responsiveness of the Turkish version of the Quality of Recovery-15 (QoR-15T) scale in adult patients undergoing elective cardiac surgery. While the QoR-15T has been validated for general surgery in Turkey, its performance remains to be established in high-risk cardiac surgery populations involving cardiopulmonary bypass and intensive care stays.Approximately 150 patients at Kocaeli City Hospital will be enrolled. The study will compare the patients' QoR-15T scores-recorded preoperatively and on the 7th postoperative day-with the Global Recovery Visual Analog Scale (VAS) to determine construct validity.

Inclusion Criteria:

• Adult patients aged 18 years and older.
• Patients scheduled for elective cardiac surgery (CABG, valve replacement, or aortic surgery).
• Patients capable of understanding and answering the Turkish version of the QoR-15 questionnaire.
• Patients who provide written informed consent.

Exclusion Criteria:

• Emergency surgeries or revision surgeries
• Patients with severe cognitive impairment or psychiatric disorders that prevent completion of the scale
• Patients who refuse to participate at any stage.

The study population consists of adult patients (aged 18 and over) who are scheduled for elective cardiac surgery (including coronary artery bypass grafting, valve replacement or repair, and aortic surgery) at Kocaeli City Hospital.