Borderline pulmonary hypertension associated with chronic hypercapnia in chronic pulmonary disease

Defining a phenotype of severe COPD patients who develop chronic hypercapnia

INTRODUCTION

Chronic hypercapnia, defined by elevated blood CO2 levels, is a serious complication most prevalent in severe COPD. It negatively impacts quality of life, increases hospitalization rates, and elevates mortality risks. However, not all severe COPD patients develop chronic hypercapnia, and its underlying mechanisms remain unclear. Identifying clinical and pathophysiological predictors of hypercapnia is essential for tailored treatment strategies. This study investigates the relationship between hypercapnia and patient characteristics, lung function, and CT scan features to identify potential therapeutic targets.

METHODS

This cross-sectional study included 1526 COPD patients from three cohorts: a standard care cohort and two research cohorts (NCT04023409; NCT03053973). Data collected included demographic and clinical information, blood gases, lung function (FEV1, FVC, TLC, RV, DLCOc), and high-resolution CT scans (lung volumes, air trapping, emphysema scores, airway wall thickness (Pi10), and diaphragm indices).

RESULTS

Hypercapnia prevalence increased with COPD severity. Hypercapnic patients were older, more likely to smoke, and had more comorbidities. They exhibited lower FEV1 and FVC, and higher RV/TLC ratios, with CT scans showing lower emphysema scores and greater Pi10. Multivariate analysis identified lower PaO2, FEV1% predicted, and emphysema scores, along with higher RV/TLC ratios and NT-proBNP levels, as independent predictors of PaCO2, collectively explaining 46.3 % of the variance.

CONCLUSION

COPD patients with chronic hypercapnia are characterized by higher smoking rates, lower PaO2 levels, poorer lung function, less emphysema, and increased airway pathology. These findings underscore the multifactorial nature of hypercapnia in COPD, highlighting the need for personalized therapeutic strategies targeting these factors to improve outcomes.

Pulmonary Vascular Disease in Chronic Obstructive Pulmonary Disease

Pulmonary hypertension (PH) is a vascular disease characterized by pulmonary artery remodeling and right heart failure. PH related to COPD is a precapillary form of the disease, with hemodynamic measurements including a mean pulmonary artery pressure of greater than 20 mm Hg, a wedge pressure of less than 15 mm Hg, and a pulmonary vascular resistance of greater than 3 WU (Woods units), categorized under the World Health Organization classification as group 3. The presence of PH in COPD has been known to increase morbidity and mortality. Limited studies have evaluated treatment options for PH related to COPD.

Risk factors associated with pulmonary hypertension in patients with active tuberculosis and tuberculous destroyed lung: a retrospective study

Pulmonary tuberculosis (TB) can result in irreversible damage and lead to tuberculous destructive lung (TDL), a severe chronic lung disease that is associated with a high mortality rate. Additionally, pulmonary hypertension (PH) is a hemodynamic disorder that can be caused by lung diseases. The objective of this study is to investigate the risk factors associated with PH in active TB patients diagnosed with TDL. We conducted a retrospective review of the medical records of 237 patients who were diagnosed with TDL, active pulmonary tuberculosis, and underwent echocardiography at the Third People' Hospital of Shenzhen from January 1, 2016, to June 30, 2023. Univariate and multivariate logistic regression analyses were performed to identify factors that correlated with the development of pulmonary hypertension. Univariate and multivariate logistic regression analyses revealed that several factors were associated with an increased risk of pulmonary hypertension (PH) in individuals with tuberculosis destroyed lung (TDL). These factors included age (OR = 1.055), dyspnea (OR = 10.728), D-dimer (OR = 1.27), PaCO2 (OR = 1.040), number of destroyed lung lobes (OR = 5.584), bronchiectasis (OR = 3.205), and chronic pleuritis (OR = 2.841). When age, D-dimer, PaCO2, and number of destroyed lung lobes were combined, the predictive value for PH in patients with TDL was found to be 80.6% (95% CI 0.739-0.873),with a sensitivity of 76.6% and specificity of 73.2%. Advanced age, elevated D-dimer levels, hypercapnia, and severe lung damage were strongly correlated with the onset of PH in individuals with active pulmonary tuberculosis (PTB) and TDL. Furthermore, a model incorporating age, D-dimer, PaCO2, and the number of destroyed lung lobes might be valuable in predicting the occurrence of PH in patients with active PTB and TDL.

Lung Disease-Related Pulmonary Hypertension

Patients with advanced lung disease can develop pulmonary hypertension and succumb to right ventricular failure/cor pulmonale. Patients with pulmonary hypertension owing to chronic lung disease, or World Health Organization group 3 pulmonary hypertension, are more limited and carry a high risk of mortality. Adjunctive therapies remain the cornerstones of treatment. Recent evidence suggests that inhaled pulmonary vasodilator therapy can be helpful in patients with pulmonary hypertension owing to interstitial lung disease. Lung transplantation may be the only life-saving option in select patients, whereas palliative care and hospice should be sought for those who are not candidates as the disease progresses.