Determinants of Peak Oxygen Uptake at Each Stage of Renal Dysfunction in Patients with Heart Disease.

BACKGROUND

Identifying the causes of low peak oxygen uptake (peak V̇ ) 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 V̇ for each stage of renal function in heart disease patients, focusing on end-tidal oxygen partial pressure ( ).

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 . Patient characteristics and CPET parameters including (rest-anaerobic threshold) were compared between the groups. The relationship between PETO and peak V̇ was also investigated for each group.

RESULTS

In total, 201 patients were analyzed. 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, 0.001). In the eGFR 45 group, left ventricular ejection fraction (LVEF) and hemoglobin (Hb) were significantly associated with peak V̇ = 0.518, 0.001 and = 0.567, 0.001, respectively), whereas was not. In the eGFR 45-59 group, age, Hb, and showed a significant association with peak V̇ ( = -0.354, = 0.006; = 0.258, = 0.007; = 0.501, 0.001; respectively). In the univariate analysis, eGFR 45-59 group showed the highest coefficient of determination of to peak V̇ ( = 0.247, 0.001).

CONCLUSIONS

The determinants of peak V̇ in heart disease patients depended on the stage of renal function. The determinants of peak V̇ in patients with eGFR 45 were LVEF and Hb, while was the strongest predictor of peak V̇ in patients with eGFR 45-59.