Pulmonary Hypertension and Fibrosis

Pulmonary hypertension (PH) is a rare but severe condition characterized by high blood pressure that affects pulmonary arteries – the vessels responsible for transporting blood from the heart to the lungs. Because of the disease, the arteries become narrowed and thickened which makes it difficult for the heart to properly pump blood. The heart can then become enlarged and weakened, which can cause other diseases such as right heart failure.

One of the greatest obstacles to advancing the field of pulmonary hypertension, a disease for which there is currently no cure, is the lack of explanation for the development of the disease in many patients. Though in those cases the disease is classified as idiopathic, pulmonary fibrosis (PF) disease remains one of the common causes of pulmonary hypertension.

Development of Pulmonary Hypertension and Fibrosis

Interstitial lung disease, a group that includes pulmonary fibrosis, is one of the most common causes for pulmonary hypertension because of the damage it does to the vessels and lungs. Pulmonary fibrosis scar the lung tissue and makes it difficult for the organ to properly work.

Pulmonary hypertension related to pulmonary fibrosis occurs when the scarred tissue affects the pulmonary arteries by compressing the vessels. The scar tissue increases resistance to blood flow from the heart to the lungs, leading to increased high pressure in the pulmonary arteries and the right heart ventricle. The two diseases are included in the classification of pulmonary hypertension associated with lung diseases or hypoxemia – which differentiates it from other causes.

Pulmonary Hypertension Fibrosis Diagnosis and Prevalence

The underlying pathogenesis of pulmonary hypertension fibrosis was described as an “over exuberant fibroproliferative process,” after being initially studied as inflammatory, according to a report, “Pulmonary Hypertension in Idiopathic Pulmonary Fibrosis,” by the American College of Chest Physicians.

Despite the poor description in scientific literature, the occurrence of the disease is between 32-85%. The only diagnostic method for PH in PF patients is right heart catheterization. Detecting the disease is difficult, as described in the study authored by Nina M. Patel, David J. Lederer, Alain C. Borczuk, and Steven M. Kawut.

According to the report: “First, IPF is an insidious disease, so that IPF is often diagnosed late (after PH is present), making the incidence of PH in the setting of IPF difficult to study. Second, the ‘gold standard’ used to diagnose resting PH is right-heart catheterization, an invasive and expensive test precluding longitudinal cohort studies with repeated measurements. Third, previous investigators have employed various methods to diagnose (and criteria to define) PH, leading to underestimates or overestimates of the occurrence of PH in this population. Last, patients referred for lung transplant have been the focus of most studies of PH in IPF because they routinely undergo right-heart catheterization.”

Treatment of Pulmonary Hypertension and Fibrosis

The study “Pulmonary hypertension and idiopathic pulmonary fibrosis: a dastardly duo,” published by the National Institutes of Health in 2013, presents an overview about the condition, explaining that the treatment of PH in patients with PF involves numerous variables that include disease severity, functional status and degree of hypoxemia.

Even though there is cure for pulmonary hypertension, there are treatments approved by the U.S. Food and Drug Administration (FDA) for patients with pulmonary fibrosis.

The most common treatments include phosphodiesterase-5 inhibitors, nonselective endothelin receptor antagonists, and prostacyclin analogues. Difficulties can occur such as worsening ventilation-perfusion mismatch induced by selective pulmonary artery vasodilator therapy.

The combination of the two conditions is associated with high mortality rate and propensity for acute decompensation, making lung transplant a consideration above pharmacological treatment.