Electrical impedance tomography in pulmonary arterial hypertension

The characterization of pulmonary arterial hypertension (PAH) relies mainly on right heart catheterization (RHC). Electrical impedance tomography (EIT) provides a non-invasive estimation of lung perfusion that could complement the hemodynamic information from RHC. To assess the association between impedance variation of lung perfusion (ΔZ(Q)) and hemodynamic profile, severity, and prognosis, suspected of PAH or worsening PAH patients were submitted simultaneously to RHC and EIT. Measurements of ΔZ(Q) were obtained. Based on the results of the RHC, 35 patients composed the PAH group, and eight patients, the normopressoric (NP) group. PAH patients showed a significantly reduced ΔZ(Q) compared to the NP group. There was a significant correlation between ΔZ(Q) and hemodynamic parameters, particularly with stroke volume (SV) (r = 0.76; P < 0.001). At 60 months, 15 patients died (43%) and 1 received lung transplantation; at baseline they had worse hemodynamics, and reduced ΔZ(Q) when compared to survivors. Patients with low ΔZ(Q) (≤154.6%.Kg) presented significantly worse survival (P = 0.033). ΔZ(Q) is associated with hemodynamic status of PAH patients, with disease severity and survival, demonstrating EIT as a promising tool for monitoring patients with pulmonary vascular disease.