TY - JOUR T1 - Ventilatory inefficiency relative to oxygen uptake and carbon dioxide output are independent predictors of mortality in pulmonary arterial hypertension JF - European Respiratory Journal JO - Eur Respir J VL - 42 IS - Suppl 57 SP - 3489 AU - Maria Clara N. Alencar AU - Roberta Pulchieri Ramos AU - Eloara V.M. Ferreira AU - Flávio Ferlin Arbex AU - Luiz Eduardo Nery AU - Jaquelina S. Ota Arakaki AU - J. Alberto Neder Y1 - 2013/09/01 UR - http://erj.ersjournals.com/content/42/Suppl_57/3489.abstract N2 - Background: Exercise intolerance is a well-established prognostic marker in a number of cardiopulmonary diseases. In pulmonary arterial hypertension (PAH), excessive ventilatory (VE) response relative to metabolic demand associated with insufficient O2 delivery are important factors impairing patients' exercise capacity. We therefore investigated whether the dynamic relationship between VE and both pulmonary carbon dioxide output (VCO2) and O2 uptake (VO2) would constitute negative prognostic markers in this patient population. Methods: Eighty-one patients (36 idiopathic and 45 with associated conditions) were followed-up for up to 5 yrs. VE/VCO2 slope (rest-to-peak data) and VO2 efficiency slope (OUES) were calculated and analyzed in association with traditional cardiopulmonary exercise test (CPET)-based measurements. Results: Fourteen patients (17 %) died during the follow-up period. Resting variables were not related to prognosis (p>0.05). Univariate analysis indicated that peak VO2, ΔVO2/Δ work rate, ΔV’E/ΔV’CO2 and OUES were associated with lower survival (p<0.05). A multiple regression analysis of dichotomized data obtained after a ROC curve analysis showed that ΔV’E/ΔV’CO2 ≥ 55 [hazard ratio (HR) (95% CI)= 11.16 (1.4-86.6); p= 0.02] and OUES ≤ 0.56 [HR 11.24 (3.5-35.8); p= 0.02] were independent predictors of mortality. Association of these findings increased OR for mortality to 18.2 (5.8-57.3), p <0.01. Conclusion: Ventilatory inefficiency relative to pulmonary gas exchange during rapidly-incremental CPET is a marker of poor prognosis in patients with PAH. ER -