Functional predictors of poor outcomes in Chagas cardiomyopathy: The value of end-tidal carbon dioxide at peak exercise.

• PETCO 2 peak and VO 2peak were lower in chagas cardiomyopathy patients with adverse events. • PETCO 2 peak and VO 2peak are independent predictors of worse prognosis. • PETCO 2 peak and VO 2peak lower than 32 mmHg and 20 mL.kg.min identify worse prognosis. Functional impairment can be detected from the onset of heart disease in patients with Chagas cardiomyopathy (ChC) and the prognostic value of the end-tidal carbon dioxide at peak exercise (PETCO 2 peak) should be investigated. To verify the prognostic value of PETCO 2 peak in patients with ChC. Seventy-six patients with ChC (49.2 ± 9.8 years, NYHA I-III) were evaluated by echocardiography and Cardiopulmonary Exercise Testing. Patients were followed up to four years and the end-point was defined as cardiovascular death, stroke, or cardiac transplantation. At the end of the follow-up period (29.0 ± 16.0 months), 16 patients (21%) had experienced adverse events. The area under the receiver operating characteristic (ROC) curve to identify the risk of adverse events by PETCO 2 peak in patients with ChC was 0.83 (95% CI: 0.69 to 0.97), and the value of 32 mmHg was the optimal cut point (70% of sensitivity and 85% of specificity). In the Kaplan-Meier diagram, there was a significant difference (p <0.001) between patients with reduced (≤ 32 mmHg) and preserved PETCO 2 peak (>32 mmHg). In the final Cox multivariate model, only reduced PETCO 2 peak (HR 4.435; 95% CI: 1.228 to 16.016, p = 0.023) and VO 2peak (HR 0.869; 95% CI: 0.778 to 0.971, p = 0.013) remained as independent predictors of poor outcome in ChC patients. Reduced PETCO 2 peak and VO2 peak demonstrated valuable prognostic value in patients with ChC. The cutoff points for both functional variables can be used during risk stratification and may help in the development of therapeutic strategies in ChC patients. [ABSTRACT FROM AUTHOR]