Goal 2: Reduce Human Disease

Development of right ventricular-targeted therapies in pulmonary arterial hypertension (PAH)

Pulmonary arterial hypertension (PAH) is a complex, progressive condition characterized by high blood pressure in the lungs and restriction of flow through the pulmonary arterial system. A great increase in the treatment armamentarium has been noted for this rare disease in the past 20 years, with 12 new PAH-targeted therapies. Though these therapies do improve cardiac performance, this is most likely due to their primary effect on the pulmonary arterial system and not by directly supporting the right ventricle (RV). The effect of PAH-targeted therapies and medications currently used in left heart disease on the adapting RV during PAH is not currently well characterized or known; novel therapies targeting the RV remain undiscovered.

Is this idea a Compelling Question (CQ) or Critical Challenge (CC)? Critical Challenge (CC)

Details on the impact of addressing this CQ or CC

Since 2006, 12 medical therapies for PAH have been approved by the FDA, which have increased survival of this rare disease from around 2.8 years to approximately 9 years; these therapies primarily act by dilating the pulmonary arteries in order to reduce pulmonary vascular resistance to blood flow. However, patients continue to die from right ventricular failure, highlighting the important relationship of the pulmonary arterial system and right ventricle (RV). Despite patients ultimately dying from RV failure, little is known about the effect of the currently available PAH-targeted therapies on RV functional support. Prostacyclins, PDE5i, and sGC agonists are thought to enhance RV contractility—though the long-term effects remain unknown—while ERAs are thought to reduce it. The direct RV effect of some potential therapies targeting the pseudo-malignancy theory of PAH is a concern, as these therapies seek to reduce the hypertrophy and angiogenesis that may actually be supporting the adapting RV. Further, therapies targeting the ventricle directly have historically been centered on the LV—for example β-adrenergic receptor blockers and RAS inhibition—and either remain controversial or without data in the RV. There remains no identified RV-specific therapy to either provide support through increase contractility or molecularly prevent the progression from RV hypertrophy to ultimate failure.

Feasibility and challenges of addressing this CQ or CC

The primary challenge of addressing this CC on the lack of RV-targeted therapies for the treatment of PAH is the comprehensive analysis and support that will need to be provided, spanning from basic to clinical science. To begin, strong support of biologic characterization of the right ventricle needs to be provided. The RV is distinctly different from the more comprehensively studied left ventricle, and subsequently responds differently to autocrine, paracrine, neuroendocrine, pressure, and pharmaceutical changes to name only a few. However, when identified, these RV biologic distinctions can be translated and tested clinically to more comprehensively and appropriately treat the RV-arterial uncoupling ultimately leading to right heart failure: through both reduction in afterload and an increase in contractility.

Name of idea submitter and other team members who worked on this idea Katherine Kroner, Michael Patrick Gray, PHA



66 net votes
75 up votes
9 down votes
Idea No. 794