Emerging phenotypes of pulmonary hypertension associated with COPD: a field guide

Abstract

Purpose of review: Pulmonary hypertension (PH) is a common complication of chronic obstructive lung disease (COPD), but clinical presentation is variable and not always 'proportional' to the severity of the obstructive disease. This review aims to analyze heterogeneity in clinical features of PH-COPD, providing a guide for diagnosis and management according to phenotypes.

Recent findings: Recent works have focused on severe PH in COPD, providing insights into the characteristics of patients with predominantly vascular disease. The recently recognized 'pulmonary vascular phenotype', characterized by severe PH and mild airflow obstruction with severe hypoxemia, has markedly worse prognosis and may be a candidate for large trials with pulmonary vasodilators. In severe PH, which might be best described by a pulmonary vascular resistance threshold, there may also be a need to distinguish patients with mild COPD (pulmonary vascular phenotype) from those with severe COPD ('Severe COPD-Severe PH' phenotype).

Summary: Correct phenotyping is key to appropriate management of PH associated with COPD. The lack of evidence regarding the use of pulmonary vasodilators in PH-COPD may be due to the existence of previously unrecognized phenotypes with different responses to therapy. This review offers the clinician caring for patients with COPD and PH a phenotype-focused approach to diagnosis and management, aimed at personalized care.

Box 1

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FIGURE 1

Algorithm for diagnosis and management of PH in COPD according to phenotype. Right heart catheterization is mandatory only if severe PH is suspected or in the work-up to lung transplant or lung reduction surgery evaluation. Assess COPD severity and manage according to current recommendations [98]. 6^th World Symposium on PH classification is considered for grouped PH [86]. CI, cardiac index; COPD, chronic obstructive lung disease; IPAH, idiopathic pulmonary arterial hypertension; mPAP, mean pulmonary arterial pressure; PH, pulmonary hypertension.

FIGURE 2

Relationship between PaO₂, mPAP and FEV₁ in COPD patients with severe PH (SPH-COPD) and in pulmonary arterial hypertension (PAH). Each bubble represents the relationship of mean values of mPAP and PaO₂ reported in case series of SPH-COPD [10,11,62^▪,63,88,95^▪,96] and PAH [93,94,95^▪]. The diameter of bubbles is proportional to the FEV₁ reported in the same studies. Patients with COPD and severe PH are consistently more hypoxemic than PAH regardless of hemodynamic severity. Thus, when mild-moderate COPD is observed, PaO₂ may be more helpful than FEV₁ in differentiating patients with PVP over concurrent mild-moderate COPD and PAH. FEV₁, forced expiratory volume in one second; mPAP, mean pulmonary artery pressure; PAH, idiopathic pulmonary arterial hypertension; PaO₂, arterial oxygen partial pressure; PVP, pulmonary vascular phenotype; SPH-COPD, COPD and severe PH.