Open Actively Recruiting

Novel Index (PIMR) in PAH


Brief Summary

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.

Study Type


Healthy Volunteers
Minimum Age
18 Years
Maximum Age

Inclusion Criteria:

  • Diagnosis of Group 1 PAH with invasive pulmonary hypertension defined as: Mean pulmonary arterial pressure ≥ 20 mmHg, pulmonary capillary wedge pressure < 15 mmHg, and pulmonary vascular resistance ≥ 3 Wood units.
  • Serum creatinine < 2.0 mg/dL
  • Able to provide informed written consent

Exclusion Criteria:

  • Other groups/forms of pulmonary hypertension (i.e. groups 2-5)
  • Contraindicated to undergo fluoroscopy and/or coronary angiography
  • Pregnancy

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Study Stats
Protocol No.
Heart/Cardiovascular Diseases
Rushi Parikh
  • UCLA Westwood
For Providers
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