In patients with pulmonary hypertension (PH), elevated pulmonary vascular resistance (PVR) levels of more than 3.0 Wood units are associated with poor prognosis, but the clinical outcomes of PVR in PH are not known. This study aims to evaluate the association between PVR and serious adverse clinical outcomes in PH.

This retrospective cohort study included a total of 40,082 patients with a history of heart failure or chronic obstructive pulmonary disease who were undergoing right heart catheterization. The researchers used Cox proportional hazards models to examine the relationship between PVR and clinical outcomes. The primary outcome of the study was all-cause mortality assessed by hazard ratios.

The all-cause mortality ratio for PVR, when modeled as a continuous variable, was increased at about 2.2 Wood units, as compared with PVR of 1.0 Wood unit. The hazard ratio (HR) for mortality was 1.71 and 1.27 for heart failure hospitalization in patients with a mean pulmonary artery pressure (mPAP) of at least 19 mm Hg and pulmonary artery wedge pressure of less than 15 mm Hg.

The research suggested that patients referred to right heart catheterization with elevated pulmonary artery pressure were at a higher clinical risk of mortality and heart failure.