Prognostic Value of Functional Exercise Test (EFX) in Cystic Fibrosis

Current guidelines for referring cystic fibrosis (CF) patients for lung transplantation, based on clinical and functional resting parameters, are insufficient to predict 3-year mortality. Previous studies have shown that sex, impaired pulmonary function, undernutrition and colonization of the respiratory tract by Pseudomonas aeruginosa are associated with a poor prognosis. Current guidelines for referral to a lung transplant center include age, sex, forced expiratory volume at one second (FEV1) below 30% predicted or a rapid decline of FEV1, in particular in young female patients, increasing frequency of exacerbations requiring antibiotic therapy, refractory or recurrent pneumothorax, recurrent hemoptysis not controlled by embolization. But, despite these criteria, near that 30% of patients are still dying while on the lung transplant waiting list, or are transplanted in high emergency. Cardiopulmonary exercise testing (CPET) in CF patients would have an interest in the following of cystic fibrosis patients. A previous study, carried out on fifty one adult patients, showed that CPET with blood gas analysis may have a prognosis value in cystic fibrosis. The authors found that a BMI < 19.8 and P(A-a)O2 peak > 43 mmHg were independently associated with a lower chance of survival.