World Cardiology Conference 2026

Abstract

Early mobilization after cardiac surgery is essential to prevent postoperative functional decline; however, it remains unclear whether the relationship between timing of ambulation and lower limb function differs according to preoperative frailty status. We conducted a retrospective observational study including 116 patients (76 pre-frail and 40 frail) who underwent cardiac surgery via median sternotomy at our hospital. Lower limb function was assessed using the Five Times Sit-to-Stand Test (5STS), and the primary outcome was the change in 5STS time from preoperative assessment to discharge. Exposure variables included the number of days from surgery to initiation of walking training, from walking training initiation to ambulation to the ward toilet, and from ward toilet ambulation to independent ambulation. Multiple linear regression analyses were performed adjusting for age, sex, operative time, postoperative complications, and length of hospital stay, followed by stratified analyses according to frailty status. Among the three mobility intervals, only the time from surgery to initiation of walking training was significantly associated with worsening 5STS performance (regression coefficient 0.45, p < 0.01). In stratified analyses, no mobility interval was significantly associated with 5STS change in the pre-frail group, whereas delayed initiation of walking training was significantly associated with greater functional decline in the frail group (regression coefficient 0.96, p < 0.01). Physiologically, early ambulation helps prevent muscle atrophy by suppressing mitochondrial dysfunction and protein degradation2). Additionally, antigravity activities such as standing and ambulation enhance cardiac output and peripheral circulation, improving oxygen delivery and metabolic efficiency, which contributes to the preservation of lower-limb endurance3). These findings suggest that delayed postoperative walking initiation is associated with lower limb functional decline after cardiac surgery, particularly among patients with preoperative frailty, highlighting the importance of early mobilization strategies tailored to frail individuals.