Background: Identifying the causes of low peak oxygen uptake (peak V ̇O2) in heart disease patients with renal dysfunction is necessary for prognostic improvement strategies. The purpose of this study was to verify the determinants of peak V ̇O2 for each stage of renal function in heart disease patients, focusing on end-tidal oxygen partial pressure (PETO2). Methods: Two hundred fifty heart disease patients who underwent cardiopulmonary exercise testing (CPET) in our institution were consecutively enrolled. Patients were divided into three groups by their estimated glomerular filtration rate (eGFR): <45, 45-59 and ≥60 mL/min/1.73 m 2 . Patient characteristics and CPET parameters including ∆PETO2 (rest-anaerobic threshold) were compared between the groups. The relationship between ∆PETO2 and peak V ̇O2 was also investigated for each group. Results: In total, 201 patients were analyzed. ∆PETO2 decreased with the deterioration of renal function (eGFR <45, 0.1 mmHg vs. eGFR 45-59, 2.4 mmHg vs. eGFR ≥60, 5.2 mmHg, p < 0.001). In the eGFR <45 group, left ventricular ejection fraction (LVEF) and hemoglobin (Hb) were significantly associated with peak V ̇O2 β = 0.518, p < 0.001 and β = 0.567, p < 0.001, respectively), whereas ∆PETO2 was not. In the eGFR 45-59 group, age, Hb, and ∆PETO2 showed a significant association with peak V ̇O2 (β = -0.354, p = 0.006; β = 0.258, p = 0.007; β = 0.501, p < 0.001; respectively). In the univariate analysis, eGFR 45-59 group showed the highest coefficient of determination of ∆PETO2 to peak V ̇O2 (R 2 = 0.247, p < 0.001). Conclusions: The determinants of peak V ̇O2 in heart disease patients depended on the stage of renal function. The determinants of peak V ̇O2 in patients with eGFR <45 were LVEF and Hb, while ∆PETO2 was the strongest predictor of peak V ̇O2 in patients with eGFR 45-59.

Background: After cardiac valve surgery, postoperative exercise capacity and psychosocial parameters of patients change significantly, both of which can affect prognosis. This study aimed to analyze and clarify the relationship between changes in perioperative exercise capacity and psychosocial factors in the early phase after valvular surgery. Methods: We enrolled 48 consecutive patients who underwent valvular surgery and studied their exercise capacity, health-related quality of life (HRQOL), anxiety disorders, depression symptoms, blood samples, and echocardiograms preoperatively and 14 days postoperatively.