Diagnosis and management of pulmonary hypertension related to chronic respiratory disease

Pulmonary hypertension in chronic obstructive pulmonary disease: current understanding, knowledge gaps and future directions

PURPOSE OF REVIEW

Despite the advent of effective and mechanistically diverse treatments for pulmonary arterial hypertension (PAH) and their positive impacts on the functional capacities and outcomes for PAH patients, the much larger population of patients with pulmonary hypertension (PH) in chronic lung diseases like chronic obstructive pulmonary disease (PH-COPD) remain without effective therapies.

RECENT FINDINGS

In this review, we will highlight advances in the understanding of PH-COPD pathobiology, the clinical impact comorbid PH has on COPD outcomes, and detail the spectrum of disease and clinical phenotypes that encompass the heterogenous disease manifestations of PH-COPD. Finally, we will examine recent studies exploring the effects of potential treatments for PH-COPD and highlight sub-populations and treatment options that warrant further study.

SUMMARY

As the PAH population-base ages and comorbid diseases become more frequently diagnosed in PAH patients, the need to clearly delineate subpopulations for clinical applications of PH therapies and research becomes even more urgent. Through an improved understanding of the clinical phenotypes of PH-COPD and the overlap with certain subpopulations of PAH, a framework for future research and potential for therapeutic impact is highlighted.

[Pulmonary hypertension associated with lung disease]

Pulmonary hypertension (PH) is a multifactorial pulmonary vascular disease. PH associated with pre-existing lung disease is common and classified as group 3 in the clinical classification. Patients with chronic obstructive or interstitial lung disease are most likely to develop PH, with up to 20% of patients showing signs of PH. Distinguishing between the symptoms of the underlying lung disease and concomitant PH can be difficult. Clinical assessment, lung function tests, laboratory tests, and echocardiography can be helpful. The hemodynamic definition of PH has recently been changed. PH associated with lung disease is a pre-capillary form by definition. A special sub-stratification in group 3 is the differentiation of hemodynamic severity. Severe PH in group 3 is defined as a pulmonary vascular resistance (PVR) greater than 5 Wood units (WU). This pulmonary vascular phenotype is characterized by rather mild to moderate impairment of lung function or lung parenchymal destruction but with severe pulmonary vascular disease or right heart strain. Currently, there are no specific PH medications approved for group 3. However, the use of specific PH medications for the pulmonary vascular phenotype is being discussed in studies or on a case-by-case basis, while in patients with a PVR below 5 WU treatment focuses on the underlying disease.