Abstract
Background: The cardiopulmonary exercise test (CPET) is used in heart failure in order to evaluate the symptoms, determine the differential diagnoses of dyspnea, consider the prognosis and survival in diseases and finally help the patient's treatment. The aim of present study was to determine the correlation between CPET results and the functional class of patients with advanced heart failure candidate for heart transplantation.
Methods: A cross-sectional study was conducted in the respiratory department of Imam Khomeini Hospital in Tehran (2016-2017). Total 86 patients (68 males and 18 females) who were candidates for cardiac transplantation were entered in this study without any history, physical examination and pulmonary functional test in favor of lung disease. The functional class was determined according to NYHA classification, and ejection fraction calculated by trans-thoracic echocardiography. The cardiopulmonary exercise test (CPET) was performed based on Bruce protocol and Gonshorn's ergospirometer cycle apparatus. All necessary information was analyzed including BMI, Heart rate at rest and Maximal activity, FEV1, FVC, FEV1/FVC, MEF 25-75, O2Saturation at rest and Maximal activity, AT, peak VO2, WR, VE Max, VT Max VD/VT, respiratory rate, pet CO2, RER, VE/VCO2, ventilatory reservation, functional class, test termination causes and Ejection fraction. The relationship between functional class and CPET parameters was determined based on obtained results.
Findings: To sum up, the most common cause of test termination was shortness of breath and generalized fatigue. The relationship between peak Vo2 and the functional class was significant and inverse (P = 0.03). The VE/VCO2 at AT and the functional class were related considerably and directly (p = 0.001).
Conclusion: This study showed that the higher grade of functional class in patients is correlated to decline in peak Vo2 and increase in VE/VCO2 ratio at AT. Therefore, VE/VCO2 ratio, that is not dependent on the patient's effort, is recommended in determination of prognosis and survival in patients with heart failure.
Keywords: Advanced heart failure, heart, lung, cardiac transplantation, cardio-pulmonary exercise test (CPET), functional class.
Graphical Abstract
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