Echocardiographic predictors of stress induced right ventricular diastolic dysfunction in non-severe chronic obstructive pulmonary disease.
Background: Pulmonary vasculopathy, right heart structural and functional abnormalities occur even in normoxemic chronic obstructive pulmonary disease (COPD) patients. Despite being associated with functional limitation, exacerbations, and disease progression, their detection and proper management is still delayed. Aim: Our aim was to establish the frequency of stress-induced right ventricular diastolic dysfunction (RVDD) in non-severe COPD patients, free of overt cardiovascular disease, who complain of exertional dyspnea and to look for echocardiographic predictors of it. Materials and
Methods: We applied cardio-pulmonary exercise testing (CPET) in 104 non-severe, COPD patients. A ramp protocol was performed. Echocardiography was done before and 1-2 min after peak exercise. Cut-off values for stress induced RVDD were E/e' >6. Receiver operating curves were constructed for echo parameters at rest to determine if any of them may discriminate stress induced RV E/e'>6 or <6. Uni- and multivariable linear regression analysis was also performed to assess the predictive power of each of them. A p-value < 0.05 was considered significant.
Results: A total of 78% of the patients had stress-induced RVDD. Right atrium volume index (RAVI) (cut-off >20.55 ml/m2; sensitivity - 86%; specificity - 86%), RV wall thickness (RVWT) (cut-off >5.25 mm; sensitivity - 100%; specificity - 63%), and RV E/A ratio at rest (cut-off >1.05; sensitivity - 79.7%; specificity - 90.5%) were the best predictors of stress RV E/e. In univariate regression analysis E/A showed the highest OR 19.73 (95% CI - 18.52-21.01); followed by RAVI - OR 3.82; (95% CI - 2.04-7.14).
Conclusion: There is a high prevalence of stress-induced RVDD in non-severe COPD patients with exertional dyspnea, free of overt cardiovascular disease. RAVI, RVWT, E/A, and E/e' ratio at rest may be used as predictors for stress RVDD and may facilitate patients' risk stratification and proper management.