Zhinan Lu1, Jie Huang1, Xingguo Sun2, Xiaoyue Tan1, Zixu Li1, Shengshou Hu1. 1. State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100037, China. 2. State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100037, China. Email:xgsun@labiomed.org.
Abstract
OBJECTIVE: To assess the cardiopulmonary exercise testing (CPET) derived performance of oxygen uptake and ventilation efficiency parameters, including oxygen uptake efficiency plateau (OUEP) , oxygen uptake efficiency slope (OUES), V·E/V·CO2 slope and lowest V·E/V·CO2, in patients with end-stage chronic heart failure (CHF) and evaluate their clinical value on monitoring cardiac function and hemodynamic status. METHODS: A total of 26 end-stage CHF patients considered for heart transplantation were enrolled in this study. CPET, echocardiography and invasive hemodynamic examinations with Swan-Ganz flowing balloon catheter were performed. Correlation analysis was made between oxygen uptake and ventilation efficiency parameters from CPET and echocardiographic and hemodynamic parameters. RESULTS: OUEP and OUES showed good correlation with peak oxygen consumption (peak V·O2) (r = 0.535, P < 0.01;r = 0.840, P < 0.001). In end-stage CHF patients, the slope of OUEP with respect to peak V·O2 is about 32, but the slope of OUES with respect to peak V·O2 is only about 2. The difference was 16 times. The change of OUEP was more sensitive and significant than those of OUES and peak V·O2 (P < 0.05). OUEP, peak V·O2 (%pred), V·E/V·CO2 slope and lowest V·E/V·CO2 were all correlated well with non-invasive hemodynamic parameters peak cardiac output (r = 0.535, P < 0.01; r = 0.652, P < 0.001; r = -0.640, P < 0.001; r = -0.606, P = 0.001 respectively) and peak cardiac index (r = 0.556, P < 0.01;r = 0.772, P < 0.001; r = -0.641, P < 0.001; r = -0.620, P < 0.001 respectively) derived from CPET, but not correlated with invasive hemodynamic parameters cardiac output and cardiac index at rest (P > 0.05). Both peak V·O2 (%pred) and V·E/V·CO2 slope were significantly correlated with invasive hemodynamic parameters systolic pulmonary arterial pressure (r = -0.424, P < 0.05; r = 0.509, P < 0.01) and mean pulmonary arterial pressure (r = -0.479, P < 0.05; r = 0.405, P < 0.05). Peak V·O2 (%pred) was also significantly correlated with pulmonary capillary wedge pressure (r = -0.415, P < 0.05), and V·E/V·CO2 slope was significantly correlated with pulmonary vascular resistance (r = 0.429, P < 0.05). CONCLUSIONS: The oxygen uptake and ventilation efficiency parameters derived from CPET, including peak V·O2, OUEP, lowest V·E/V·CO2 and V·E/V·CO2 slope etc, are objectively monitoring and evaluating cardiac function and hemodynamic status. And they are useful for optimizing clinical management of patients with end-stage CHF.
OBJECTIVE: To assess the cardiopulmonary exercise testing (CPET) derived performance of oxygen uptake and ventilation efficiency parameters, including oxygenuptake efficiency plateau (OUEP) , oxygen uptake efficiency slope (OUES), V·E/V·CO2 slope and lowest V·E/V·CO2, in patients with end-stage chronic heart failure (CHF) and evaluate their clinical value on monitoring cardiac function and hemodynamic status. METHODS: A total of 26 end-stage CHFpatients considered for heart transplantation were enrolled in this study. CPET, echocardiography and invasive hemodynamic examinations with Swan-Ganz flowing balloon catheter were performed. Correlation analysis was made between oxygen uptake and ventilation efficiency parameters from CPET and echocardiographic and hemodynamic parameters. RESULTS:OUEP and OUES showed good correlation with peak oxygen consumption (peak V·O2) (r = 0.535, P < 0.01;r = 0.840, P < 0.001). In end-stage CHFpatients, the slope of OUEP with respect to peak V·O2 is about 32, but the slope of OUES with respect to peak V·O2 is only about 2. The difference was 16 times. The change of OUEP was more sensitive and significant than those of OUES and peak V·O2 (P < 0.05). OUEP, peak V·O2 (%pred), V·E/V·CO2 slope and lowest V·E/V·CO2 were all correlated well with non-invasive hemodynamic parameters peak cardiac output (r = 0.535, P < 0.01; r = 0.652, P < 0.001; r = -0.640, P < 0.001; r = -0.606, P = 0.001 respectively) and peak cardiac index (r = 0.556, P < 0.01;r = 0.772, P < 0.001; r = -0.641, P < 0.001; r = -0.620, P < 0.001 respectively) derived from CPET, but not correlated with invasive hemodynamic parameters cardiac output and cardiac index at rest (P > 0.05). Both peak V·O2 (%pred) and V·E/V·CO2 slope were significantly correlated with invasive hemodynamic parameters systolic pulmonary arterial pressure (r = -0.424, P < 0.05; r = 0.509, P < 0.01) and mean pulmonary arterial pressure (r = -0.479, P < 0.05; r = 0.405, P < 0.05). Peak V·O2 (%pred) was also significantly correlated with pulmonary capillary wedge pressure (r = -0.415, P < 0.05), and V·E/V·CO2 slope was significantly correlated with pulmonary vascular resistance (r = 0.429, P < 0.05). CONCLUSIONS: The oxygen uptake and ventilation efficiency parameters derived from CPET, including peak V·O2, OUEP, lowest V·E/V·CO2 and V·E/V·CO2 slope etc, are objectively monitoring and evaluating cardiac function and hemodynamic status. And they are useful for optimizing clinical management of patients with end-stage CHF.