Correlation of Echocardiographic Variables with Exercise Capacity in Patients with Pulmonary Hypertension due to Congenital Heart Diseases

Abstract

Background Pulmonary arterial hypertension (PAH) is a disease of the pulmonary circulation with resultant effects on the right heart. Conceptually, left heart anatomy and function should be normal in patients with PAH. However, the RV and left ventricle (LV) do not function in isolation, sharing a common pericardial sac and inter-ventricular septum which in turn refers to the significance of assessment of both ventricles which has implications for patient prognosis with PAH. Aim Study the correlation between echocardiographic hemodynamic parameters and functional capacity in patients with pulmonary hypertension due to congenital heart disease and detection which parameter is the most independent predictor of functional capacity in patients with PAH-CHD. Methodology The study was conducted in the period from November 2016 to September 2017 including 34 patients who had been diagnosed with pulmonary arterial hypertension associated with congenital heart diseases (PAH-CHD). All of them were recruited from the congenital heart diseases unit at Ain Shams University hospital. The studied group was divided into two groups in a cross-sectional study: Group I: This included 21 patients with functional capacity according the 6MWT less than 330 m as an average for all subjects. Group II: This included 13 patients with functional capacity more than 330 m. Patients’ participation was voluntary and the subject had the right to withdraw from the study at any time without affecting his/her further medical care. Results The whole study population was divided according to the 6MW distance into two groups less than 330 and more than or equal 330 m. Comparing the 6MWD of each patient with the different Echocardiographic variables of systolic & diastolic dysfunction revealed that the group of shorter 6MW distance had higher RVSP, MPAP, E/e’ ratio, LVMPI and RVMPI, while they had lower LV e’ TDI, LV GRS, RV FAC and RV GLS (less negative value). Multivariate analysis of these Echocardiographic variables revealed that MPAP is independent predictor of 6MWD & thus an independent predictor of functional capacity in PAH-CHD patients. Conclusion Assessment of RV and LV function in PAH-CHD patients is important. Strain measurement by STE provides valuable information on the quantitative RV and LV functional assessment in the setting of volume and pressure overload. The MPAP and saturation were found to be the most independent predictors affecting the functional capacity of the patients with PAH-CHD. Recommendations Assessment of functional capacity in patients with PH using the 6MWT is recommended as a routine investigation from diagnosis and during follow-up and correlated with the echocardiographic variables, it has been shown to be practical and feasible and provides an easy and not expensive tool for clinical and prognostic assessment.