Hemodynamic indices in pulmonary hypertension: a narrative review

Background and Objective: Pulmonary hypertension (PH) is defined as a mean pulmonary artery pressure (mPAP) >20 mmHg and its presence is associated with worse outcomes. A comprehensive hemodynamic evaluation of the pulmonary circulation is essential for diagnosis, hemodynamic classification, and prognostication. A multitude of indices assess different aspects of the pulmonary circulation but there are no reviews that describe their specific value in PH. Methods: We performed a thorough literature search of relevant articles in English from 1970-2021 using PubMed. Key Content and Findings: In this article, we present both static and dynamic indices used for the hemodynamic assessment of PH. While some of these indices are routinely used in clinical practice, including cardiac index (CI), stroke volume (SV), and pulmonary vascular resistance (PVR); others such as pulmonary artery compliance (PAC), pulmonary effective arterial elastance (Ea), and pulmonary artery pulsatility index (PAPi) are gaining popularity by enhancing the understanding of different aspects of the pulmonary circulation. We described the advantages and pitfalls of various indices, including when to use them in the hemodynamic evaluation of patients with PH. Conclusions: A variety of indices measuring different aspects of the right ventricle (RV)-pulmonary arteries (PA) system provide valuable information in patients with PH. However, it remains important to develop and validate indices that provide a comprehensive hemodynamic evaluation to improve outcomes in patients with PH.