Assessment of Right Ventricular Adaptability to Pressure Overloading for Critical Therapeutic Decision-Making Processes.

Right ventricular pressure overloading [RVPO] with secondary maladaptive RV remodeling and progressive myocardial dysfunction in patients with pulmonary hypertension associated with left-sided heart diseases [PH-LHDs] and in those with pulmonary arterial hypertension [PAH] still remains one of the most complex challenges in cardio-pulmonary medicine. Despite the advances in the optimization of diagnostic tools and the expansion of treatment options, there is still a great need for further research to gain a better understanding of the major pathophysiological mechanisms involved in both the RV responses to PO and to find new possibilities to stop the progression of the alterations inside the pulmonary arterial circulation [PAC]. This article summarizes current knowledge about the particularities of the RV structural and functional responses to abnormal PO and also provides an overview of the benefits and limitations of the currently available tools for clinical evaluations of the RV adaptability to high afterload. A major focus of this review relates to the possibilities for obtaining evidence about the existence of a still remaining adaptability to a normal afterload in an over-burdened RV, in case of abolition of the pathological PO and, in this regard, to also evaluate the clinical usefulness of the RV adaptability estimation for certain critical therapeutic decisions. Among the most important conclusions of this updated overview are: 1. Whereas single parameters are insufficiently reliable for the evaluation of RV dysfunction and for predictions of its prognostic relevance across the whole spectrum of RVPO, properly selected and integrated multiparametric approaches had meanwhile unequivocally proved that they can usually become sufficiently reliable. 2. Multiparametric approaches can substantially improve the prediction of a preserved RV responsiveness to the abolition of its steady PO by reversal of RV maladaptive remodeling and by the normalization of RV pump function. Such a prediction, which can be decisive for therapeutic decision-making especially in candidates for ventricular assist device [LVAD] implantation or thoracic organ transplantation, can have a crucial impact on patient survival. 3. The complex and temporally highly variable interactions between certain structural and functional changes in both the PAC and in the hemodynamic overloaded right-sided heart, as well as between the two ventricles, can often hamper the interpretation of certain changes in the measured parameters and even relevantly alter their reliability. Additionally, the progressive aggravation of a secondary tricuspid regurgitation [TR] has a particularly high negative (often also misleading) impact on the diagnostic and prognostic relevance of RVPO evaluations.