Coronary artery bypass grafting (CABG) may be associated with prolonged recovery, particularly in high-risk patients. Although preoperative rehabilitation has shown promising results, evidence remains limited because of heterogeneous intervention protocols and variations in postoperative care. This study aims to investigate the effects of a structured inpatient physiotherapy program initiated at least two days before surgery and continued postoperatively, compared with the same structured physiotherapy program provided only during the postoperative period, in high-risk CABG patients. The primary outcome is hospital length of stay. Secondary outcomes include intensive care unit length of stay, C-reactive protein, neutrophil-to-lymphocyte ratio, hemoglobin, dyspnea, and fatigue.