Noninvasive clinical tools predict severe pulmonary hypertension in COPD

The combination of echocardiography, N-terminal pro-B-type natriuretic peptide and pulmonary artery to ascending aorta diameter ratio predicted severe pulmonary hypertension in patients with COPD with high sensitivity and specificity.

“The 6th World Symposium on Pulmonary Hypertension (WSPH) proposed hemodynamic thresholds for the classification of COPD with no pulmonary hypertension, mild to moderate pulmonary hypertension and severe pulmonary hypertension,” Gabor Kovacs, MD, from the department of pulmonology at the University Clinic of Internal Medicine, Institute for Medical Informatics at University Hospital Graz, Austria, and colleagues wrote. “However, little information is available regarding which clinical variables and noninvasive clinical tools predict the presence of severe pulmonary hypertension in COPD, that is, which patients with COPD have a higher risk of severe pulmonary hypertension and should undergo diagnostic right heart catheterization. In addition, little is known about the prognostic relevance of the proposed stratification and how the severity of airflow limitation and pulmonary vascular disease contribute to mortality.”

Researchers conducted a retrospective analysis of 142 consecutive patients with COPD (mean age, 68.1 years; 44% women) with suspected pulmonary hypertension who underwent in-depth clinical evaluation from 2005 to 2018. Researchers also analyzed clinical variables that may be indicative of severe pulmonary hypertension or death.

Median FEV₁ was 55% predicted and mean pulmonary arterial pressure was 35 mm Hg.

The researchers reported high positive and negative predictive values when combining echocardiographic systolic pulmonary arterial pressure 56 mm Hg and greater, N-terminal pro-B-type natriuretic peptide plasma levels of at least 650 pg/mL and pulmonary artery to ascending aorta diameter ratio on CT scans of at least 0.93 to predict severe pulmonary hypertension.

“When a patient meets these three criteria, the probability of severe pulmonary hypertension is 94% (29/31). This suggests that patients demonstrating all three criteria should be referred to an expert center for right heart catheterization and evaluation for individualized therapy,” the researchers wrote. “Even in patients demonstrating only two of these criteria, the probability of severe pulmonary hypertension was 62%.”

Airflow limitation (P = .002), Global Initiative for Chronic Obstructive Lung Disease (GOLD) stages 1 to 2 vs. stage 3 (HR = 1.56; 95% CI, 0.9-2.71), GOLD stages 1 to 2 vs. stage 4 (HR = 3.45; 95% CI, 1.75-6.79) and pulmonary hypertension severity (HR = 1.85; 95% CI, 1.15-2.99; P = .012) were all independently associated with survival.

Combining GOLD stages 3 and 4 airflow limitation and severe pulmonary hypertension demonstrated the poorest survival in this cohort compared with GOLD stages 1 to 2 combined with nonsevere pulmonary hypertension (HR = 3.26; 95% CI, 1.62-6.57; P = .001), according to the researchers.

“Further studies to validate these findings are warranted,” the researchers wrote.