Which Is the Best Companion of an Endothelin Receptor Antagonists in Pulmonary Hypertension, Sildenafil or Tadalafil? A Systematic Review and Meta-Analysis of Invasive Hemodynamic Data

Background: The most widely used dual therapy in Pulmonary arterial hypertension (PAH) is Endothelin receptor antagonist (ERA) alongside a phosphodiesterase inhibitor. Among multiple ERAs and PDE-5i, the commonest to be used is ERA+Sildenafil; there are suggestions that sildenafil bioavailability is reduced by ERA, this review aimed at comparing ERA+Sildenafil and ERA+Tadalafil in treatment of pulmonary arterial hypertension. Methodology:For this purpose, a literature search has been implemented with the following keywords: ERA+Sildenafil vs. ERA+Tadalafil, PAH; inclusion criteria covered clinical trials or retrospective studies comparing the two treatment regimens; and assessing invasive hemodynamics (mean pulmonary artery pressure (mPAP) and pulmonary vascular resistance (PVR)), studies were excluded if data of pulmonary hemodynamics were not provided. Results: This systematic review analyzed the results of two retrospective studies Sitbon and Grunig reports, the ERA+Sildenafil regimen comprised 160 patients vs. 62 in the ERA+Tadalafil regimen, The mPAP was significantly lower in the ERA+Tadalafil group, while a lower PVR was seen in the same group but not achieving a significant P value. Conclusion: Despite the scarcity of the included studies, this systematic review constitutes one of the few clinical evidences that Tadalafil might be best suited for dual therapy with ERA. It also highlights a gap between of literature, in the absence of clinical trials that can prove our results.