Patients with idiopathic pulmonary arterial hypertension (PAH) are more likely to have worse outcomes with decreased right atrial (RA) function, suggesting that RA function may play a role in PAH progression.
A prospective study published in the International Journal of Cardiology included 104 patients with idiopathic PAH who underwent strain and strain rate (SR) analysis. At a mean follow-up of 22 months, 29% of patients (n=30) had experienced a clinical worsening event. In 21 patients, this event was a worsening of PAH, in 8 patients it was initiation of intravenous or subcutaneous prostanoids, and in 1 patient, it was death. During follow-up, a total of 7 patients died, or 7% of the total patient population.
Among patients who experienced clinical worsening, baseline strain and SR analysis demonstrated worse right ventricular (RV) and RA function as well as poorer reservoir, conduit, and contractile function than event-free patients.
Results of univariate analysis showed that RA reservoir function at SR analysis was inversely related to RA pressure (-0.65; P <.001) and directly associated with cardiac index (0.5; P <.001). Event rates and mean survival times free of clinical worsening were 6.1% and 23.5 months among patients with normal RA and RV SR, 45% and 20.9 months in patients with impaired RA and normal RV SR, 56.2% and 17.7 months in patients with normal RA and impaired RV SR, and 87.5% and 12.9 months in patients with impaired RA and RV SR.
The investigators concluded that SR analysis results demonstrated that RA contractile function was more impaired in the clinical event group at baseline, suggesting that failure of the compensatory mechanism — that is, greater relative contribution to RV diastolic filling in more compromised RVs— may contribute to disease progression.
Furthermore, abnormal RA myocardial deformation characteristics provide additional independent prognostic value over clinical and standard echocardiography parameters. However, further studies are necessary to corroborate the value of RA deformation in patients with idiopathic PAH.
D’Alto M, D’Andrea A, Di Salvo G, et al. Right atrial function and prognosis in idiopathic pulmonary arterial hypertension [published online August 24, 2017]. Int J Cardiol. doi:10.1016/j.ijcard.2017.08.047