Behavior of right atrial strain in patients with advanced idiopathic pulmonary arterial hypertension after initiation of specific combined therapy

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Abstract Background Right atrial (RA) function has emerged as an important determinant of outcome in pulmonary arterial hypertension (PAH). However, studies exploring RA function and assessing its behavior in response to specific PAH combination therapy, independent of RA size in patients with PAH is not adequately investigated. Purpose Assess the behavior of strain based measures of RA in response to combined PAH therapy, independent of RA size in patients with PAH. Methods RA peak longitudinal strain (PLS) and peak active contraction strain (PACS) were retrospectively assessed in 38 patients with advanced idiopathic pulmonary arterial hypertension (IPAH) who were referred to Aswan heart Centre and not receiving proper GDMT; at baseline and during follow-up after initiation of specific PAH combination therapy in the form of either Sildenafil/Bosentan or Sildenafil/Macitentan. Results Most of the patients were females with median (IR) age 34 (27–39) years. All patients presented with dyspnea WHO-FC III. At baseline, all patients were receiving only monotherapy in the form of sildenafil. Median (IR) time to echocardiographic follow-up was 11 (8–18) months. Patients presented with markedly right ventricle (RV) and RA enlargement, depressed RV systolic function, and reduced RA strain parameters compared with values previously reported in healthy controls. Among various baseline associations of the RA PLS, the strongest were with baseline RA area (rho: −0.659; p<0.001) and RVEF by CMR (rho: 0.570; p<0.001). At follow up; RA PLS and PACS significantly increased (16.6 vs 24 and 7.06 vs 11.42, respectively: p<0.001); however, RA area did not show significant decrease. Only RV TDI & FAC showed significant improvement among different RV function parameters measured by echocardiography. During the follow up period, 11 out of 38 patients (28.9%) were hospitalized. RA PLS change was significantly lower in the hospitalized group than the non-hospitalized group (4.40 vs 10.2; p=0.014). RA PLS change was independently associated with hospitalization in the multivariate regression analysis (95% CI: −0.061 to −0.010; p=0.008). Conclusion Initiation of specific PAH combination therapy in undertreated patients with IPAH showed improvement in RA strain parameters despite no change in RA area during follow up. Funding Acknowledgement Type of funding sources: None.