PVR predicts death in patients with bronchiectasis-associated pulmonary hypertension

Pulmonary vascular resistance (PVR) may be used to distinguish severe (PVR >4 Wood Units) from nonsevere pulmonary hypertension (PVR ≤4 Wood Units) among patients with bronchiectasis-associated pulmonary hypertension (BAPH) and identify those who are at higher risk of mortality, a study suggests. 

"The utilization of a PVR cutoff value of 4.0 Wood Units provides enhanced prognostic capabilities for predicting mortality,” the researchers said. 

This retrospective analysis involved 139 consecutive patients diagnosed with BAPH based on right heart catheterization, enrolled between January 2010 and June 2023. The research team analysed the baseline clinical characteristics and haemodynamic assessment of the participants. 

The survival time for each patient was calculated in months from the date of diagnosis until the date of death or until their last visit. 

The estimated survival rates of BAPH patients were 89.5, 70, and 52.9 months at 1-, 3-, and 5-year intervals, respectively, with a median survival time of 67 months. [J Hypertens 2024;42:1703-1710] 

In multivariate analysis, increased age (adjusted hazard ratio [aHR], 1.042, 95 percent confidence interval [CI], 1.008–1.076; p=0.015) and elevated PVR (aHR, 1.115, 95 percent CI, 1.015–1.224; p=0.023) significantly correlated with a higher risk of all-cause mortality. 

On the other hand, higher BMI was associated with a reduced risk of all-cause mortality (aHR, 0.915, 95 percent CI, 0.856–0.979; p=0.009). 

Based on receiver-operating characteristic analyses, a cutoff value for PVR at 4 Wood Units predicted all-cause mortality within 3 years (area under the curve, 0.624; specificity, 87.5 percent; sensitivity, 35.8 percent; p<0.05). Specifically, patients with a PVR >4 Wood Units were at increased risk of all-cause death compared with those with ≤4 Wood Units (aHR, 2.392, 95 percent CI, 1.316–4.349; p=0.019). 

Additionally, no significant differences were noted in age, sex, BMI, WHO functional class, 6-min walk distance, and NT-proBNP levels at baseline between patients with PVR >4 Wood Units and those with PVR ≤4 Wood Units. 

“Our findings indicate that patients diagnosed with BAPH exhibit significantly compromised functional status and haemodynamics,” the researchers said. “Moreover, these patients have an estimated 3-year survival rate of 70 percent, with a median survival time of 67 months.” 

Prognostic benefit

The researchers also noted how the increase in right ventricular afterload, which is primarily attributed to PVR, could enable the transition of right ventricle from adaptive hypertrophy to decompensated heart failure. In addition, more and more evidence underscore the prognostic significance of PVR in pulmonary hypertension with various causes. [Clin Respir J 2018;12:915-921] 

Previous studies show that elevated PVR predicts mortality in patients with chronic obstructive pulmonary disease or interstitial lung disease (ILD). [Eur Respir J 2021;58:2100944; Eur Respir J 2021;58:2101483; J Heart Lung Transplant 2021;40:1009-1018; Eur Respir J 2008;31:1357-1367] 

Notably, an earlier study found that a PVR >5 Wood Units appeared to be a better marker for identifying patients with poor prognosis as opposed to mean pulmonary arterial pressure at least 33 mm Hg. [Eur Respir J 2021;58:2100944] 

Additionally, in patients with ILD-associated pulmonary hypertension, a PVR >5 Wood Units significantly correlated with worse survival than those with PVR ≤5 Wood Units. [Eur Respir J 2021;58:2101483] 

“Pulmonary hypertension is a severe complication of bronchiectasis, characterized by elevated PVR and subsequent right heart failure,” the researchers said.