Novel Index (PIMR) in PAH

PAH hospitalization or all-cause mortality at 1 year,PIMR change from baseline,RV-IMR

The chief regulator of resistance in pulmonary arterial hypertension (PAH) is the small
 arteries. In the heart, the invasive measurement of the resistance of the small arteries has
 been shownto be safe, easy, reliable, and prognostic. This study is intended to translate
 prior work in heart arteries to the PAH space and invasively measure the resistance of the
 small arteries of the lung (pulmonary index of microcirculatory resistance [PIMR]) and the
 coronary artery supplying the right ventricle (acute marginal of the RCA; RV-IMR).
 Importantly, these measurements will be made during standard of care cardiac catheterizations
 (right heart catheterization [RHC] +/- left heart catheterization). The correlation between
 these new indices and the standard ones measured during RHC typically used to determine the
 severity of pulmonary hypertension will be analyzed. In addition, among newly diagnosed
 patients, the study will evaluate how these indices change 6 months after starting treatment.
 Finally, the association of these indices with clinical outcomes at 1 year will be assessed.
 The findings from this study may deliver an immediate impact to patient care by identifying a
 new metric to help better identify those who may benefit from a more intensive, personalized
 treatment regimen.