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Mildly elevated pulmonary vascular resistance and worsened survival in PH-ILD: an opportunity for earlier diagnosis and intervention?
  1. Steven J Cassady1,
  2. Bradley A Maron1,2
  1. 1 Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
  2. 2 University of Maryland-Institute for Health Computing, Bethesda, Maryland, USA
  1. Correspondence to Dr Bradley A Maron, University of Maryland-Institute for Health Computing 6116 Executive Blvd, North Bethesda, Bethesda, MD 20852, USA; BMaron{at}

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Pulmonary hypertension (PH) is a feared complication of interstitial lung disease (ILD) owing to increased risk for hospitalisation and mortality among affected patients. The development of PH in ILD is attributed to several pathobiological mechanisms that often converge to remodel pulmonary arterioles including hypoxic pulmonary vasoconstriction, endothelial dysfunction, inflammation, increased oxidant stress and the pathogenic effects of parenchymal fibrosis on the alveolar-capillary interface.1

The classical definition of precapillary PH used a mean pulmonary arterial pressure (mPAP) ≥25 mm Hg and pulmonary vascular resistance (PVR) ≥3 Wood units (WU), but these haemodynamic criteria were based largely on consensus opinion in the absence of normative data or information on the association between cardiopulmonary hemodynamics and outcomes. A retrospective meta-analysis involving data from healthy volunteers suggested that the upper limit of normal mPAP is ~20 mm Hg, which converged with findings in large referral cohorts suggesting that mPAP>20 mm Hg is common and associated with a substantial increase in mortality risk.2 3 Similarly, data on PVR suggest that values ≥2 WU are clinically important and have significant associations with mortality and hospitalisation for heart failure.4 These and other observations supported the recent revision to the haemodynamic criteria that defines precapillary PH as mPAP>20 mm Hg, PVR>2 WU, and pulmonary artery wedge pressure <15 mm Hg.5 6

Since most outcomes data are from unselected referral cohorts, there is an overarching …

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  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests BM reports personal fees from Actelion Pharmaceuticals, personal fees from Tenax, personal fees from Regeneron, grants from Deerfield Company, grants from 5R01HL139613-03, grants from NIH R01HL163960, grants from U54HL119145 and Boston Biomedical Innovation Center (BBIC), grants from Brigham IGNITE award, grants from NIH R01HL153502, grants from NIH R01HL155096-01, grants from Cardiovascular Medical Research Education Foundation, outside the submitted work. In addition, BM has a patent PCT/US2019/059890 pending to None, a patent #9605047 issued to None, a patent PCT/US2020/066886, pending to None, and a patent BWH 2023-152 - 29618-0438P02 pending to None.

  • Provenance and peer review Commissioned; internally peer reviewed.

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