Background: Isolated post-capillary pulmonary hypertension (Ipc-PH) is characterized by elevated left atrial pressures that are passively transmitted upstream, whereas combined pre- and post-capillary PH (Cpc-PH) demonstrates additional reactive changes in pulmonary vasculature. The increased load imposed on the right ventricle (RV) influences left ventricular (LV) mechanics by means of interventricular interaction. However, there is lack of evidence to substantiate the effect of possible additional alterations in the arterio-ventricular (AV) coupling and their effect on LV function. Considering the discrepant RV load in Cpc-PH and Ipc-PH, we sought to investigate whether these two conditions are also characterized by differential alterations in AV coupling.
Methods and results: Invasive hemodynamic and echocardiographic data of 120 patients with PH due to severe rheumatic mitral stenosis before and immediately after percutaneous valvulotomy, along with 40 age-matched healthy controls, were analyzed. Effective arterial (E a) and ventricular elastance (E es) were measured. PH patients demonstrated elevated LV afterload (E a) along with AV uncoupling, and these derangements were more evident in the Cpc-PH group [E a: 3.3 (2.3-5.4) vs 2.6 (2.1-3.5) mmHg/mL, E a/E es: 0.73 (0.6-0.9) vs 0.88 (0.7-1.2), p < 0.05]. In addition, PH was associated with reduced LV deformation, which was mainly determined by elevated E a, while the effect of interventricular interaction was limited to the septal wall.
Conclusions: Our results suggest that in addition to the interventricular interaction, an abnormal AV coupling contributes to the altered LV mechanics that has been associated with adverse prognosis in Cpc-PH.
Keywords: Elastance; Pulmonary hypertension; Stiffness; Strain; Ventricular function.