Pulmonary Hypertension in Chronic Lung Diseases

Abstract

Chronic obstructive lung disease (COPD) and diffuse parenchymal lung diseases (DPLD), including idiopathic pulmonary fibrosis (IPF) and sarcoidosis, are associated with a high incidence of pulmonary hypertension (PH), which is linked with exercise limitation and a worse prognosis. Patients with combined pulmonary fibrosis and emphysema (CPFE) are particularly prone to the development of PH. Echocardiography and right heart catheterization are the principal modalities for the diagnosis of COPD and DPLD. For discrimination between group 1 PH patients with concomitant respiratory abnormalities and group 3 PH patients (PH caused by lung disease), patients should be transferred to a center with expertise in both PH and lung diseases for comprehensive evaluation. The task force encompassing the authors of this article provided criteria for this discrimination and suggested using the following definitions for group 3 patients, as exemplified for COPD, IPF, and CPFE: COPD/IPF/CPFE without PH (mean pulmonary artery pressure [mPAP] <25 mm Hg); COPD/IPF/CPFE with PH (mPAP ≥25 mm Hg); PH-COPD, PH-IPF, and PH-CPFE); COPD/IPF/CPFE with severe PH (mPAP ≥35 mm Hg or mPAP ≥25 mm Hg with low cardiac index [CI <2.0 l/min/m(2)]; severe PH-COPD, severe PH-IPF, and severe PH-CPFE). The "severe PH group" includes only a minority of chronic lung disease patients who are suspected of having strong general vascular abnormalities (remodeling) accompanying the parenchymal disease and with evidence of an exhausted circulatory reserve rather than an exhausted ventilatory reserve underlying the limitation of exercise capacity. Exertional dyspnea disproportionate to pulmonary function tests, low carbon monoxide diffusion capacity, and rapid decline of arterial oxygenation upon exercise are typical clinical features of this subgroup with poor prognosis. Studies evaluating the effect of pulmonary arterial hypertension drugs currently not approved for group 3 PH patients should focus on this severe PH group, and for the time being, these patients should be transferred to expert centers for individualized patient care.

Pulmonary Hypertension in Patients with Chronic Obstructive Pulmonary Disease: A Review for Definition, Epidemiology, Pathology, and Diagnosis

“…Proportional PHT is based on the assumption that the underlying parenchymal remodeling process, accompanied by hypoxia, results in an increase in pulmonary vascular resistance, leading to a "natural" loss in the area of total vascular crosssection.13 Non-proportional PHT is the presence of an unexpectedly developing PHT from pulmonary parenchymal damage.These patients have less airway obstruction, more severe hypoxia and lower carbon dioxide diffusion capacity (DLCO) [12]. The possible mechanisms are 1) progressive vascular remodeling is triggered by chronic parenchymal disease, independent of pulmonary dysfunction or 2) it can be explained as an independent, coincidental manifestation of the present lung disease [13].…”

“…In addition, this terminology should be abandoned and PHT should be defined as described below for patients with COPD, idiopathic pulmonary fibrosis (IPF) or chronic pulmonary fibrosis and emphysema (CPFA), provided that the measurements are made at rest and if necessary under supportive oxygen therapy [13] There may also be COPD/IPF/CPFA (<25 mmHg) without PHT COPD/IPF/CPFA (mean PAP ≥ 2 5 mmHg) with PHT; PHT-COPD; PHT-IPF; PHT-CPFA PHT detected in patients with COPD can also be the pulmonary arterial hypertension (PAH) (group 1), which has been found incidentally. However, it may be difficult to distinguish between group 3 and group 1 when the respiratory function is normal or mildly impaired, and when there is no or minimal damage to the airway or lung parenchyma in the computed tomography.…”

“…However, it may be difficult to distinguish between group 3 and group 1 when the respiratory function is normal or mildly impaired, and when there is no or minimal damage to the airway or lung parenchyma in the computed tomography. In these cases, patients should be directed to the experienced centers for the differential diagnosis [13].…”

“…Mild-to-moderate PHT was common in severe COPD cases, whereas severe PHT was rare [13,20]. Thabut et al reported a mean PAP>25 mmHg in 50% of COPD patients who were scheduled for lung transplantation or lung volume reduction surgery.…”

Derivation of a Screening Tool to Identify Patients with Right Ventricular Dysfunction or Tricuspid Regurgitation after Negative Computerized Tomographic Pulmonary Angiography of the Chest

“…PH has multiple etiologies, including idiopathic, hereditary, connective-tissue disease, HIV, congenital heart disease, and portal hypertension (collectively termed "pulmonary arterial hypertension" [PAH]), or it may occur as a secondary complication of treatable diseases, including left heart disease, chronic lung disease, and sleep-disordered breathing. [13][14][15][16][17] However, although PH has major implications on morbidity and mortality, recent studies suggest that it is frequently overlooked and underrecognized. 18,19 Early diagnosis and treatment improve outcomes.…”