Pulmonary Hypertension refers to a condition in which an individual has mean pulmonary artery pressure more than or equal to 25 mmHg and PAOP, which is also known by the name of pulmonary artery occlusion pressure, of less than or equal to 15 mmHg.
PH associated with lung disease such as interstitial lung disease, COPD, and breathing affected due to sleep also known by the name of hypoxia. These are all classified under group III as per WHO guidelines. Idiopathic pulmonary fibrosis, combination of pulmonary fibrosis along with emphysema, and being in high altitudes for long period of times are also linked with PH. Mild elevation of pulmonary arterial pressure must need immediate medical attention before progress to severe form. PH is considered to be very severe when an individual’s overall heart functioning in the form of its output gets decreased and pressure in the pulmonary artery is more than or equal to 35 mmHg.
COPD is quite a common medical condition and individuals with severe form of COPD have pulmonary pressures which are very high. IPF and CPFE are seen in approximately 10-15% and 40-50% of patients. Both are a risk to develop a severe form of PH and prognosis is very poor. PH associated OSA ranges from mild to moderate. Severe form occurs when OSA is associated with obesity along with hypoventilation syndrome. A very less is known about the prevalence of PH in sleep-disordered breathing diseases.
What is Group 3 Pulmonary Hypertension?
Pulmonary hypertension associated with lung diseases occur because of a spike im pulmonary vascular resistance. This causes abnormal changes in pulmonary vasculature remodeling, which is a consequence of inflamed lung tissues and airways. Another reason for this condition is poor gas exchange with hypoxic vasoconstriction along with fibrotic lung changes. Group III Pulmonary Hypertension also causes intima-media thickness, which is mainly due to hypoxia disorder; an increase in the pressure in the pulmonary artery, decreased distention of blood vessels, and inefficiency of the lungs to employ more blood vessels for gas exchange when exercising are some of the outcomes of the group III. Like group I, group III PH is also associated with pumping of tight ventricle against high tension which is a risk factor of heart failure.
Diagnostic Assessment
Echocardiogram, Right heart catheterization, PFTS to characterize lung disease and gas exchange, CT scan, and thread mill test are performed to identify the group.
Echocardiogram is the first screening done to identify the cause of the condition. Right heart catheterization is also an imperative test to assess the candidacy for lung transplantation and the overall prognosis; clinical status of the patients, and unequal gas exchange (ventilatory impairment). It is also helpful for identifying left heart disease which may be playing a part in Pulmonary Hypertension (WHO Group 2), severe PH and further therapy assessment.
Treatment for Group III
There are no drugs for treating group III PH disease at present. Many drugs are on trial and yet to be approved by FDA. Patients with a severe condition of group 3 PH must be considered for referral to professional clinical center. Prostanoids, endothelin receptor antagonists, soluble guanylate cyclase stimulators, and phosphodiesterase-5 inhibitors are effective therapies for Pulmonary Hypertension associated with lung disease; however, much information is not available because the clinical trial is at the insignificant level.
Administration of prostanoids causes hemodynamic improvement in some patients having lung diseases. They are administered to patients through inhalation process and best prostanoid available in the market are iloprost and treprostinil. Endothelin receptor antagonists’ example, macitentan, ambrisentan, and bosentan are some of the oral vasodilators that have been looked upon in lung fibrosis patients to some level.
Soluble guanylate cyclase stimulators (example sildenafil, tadalafil; riociguat) and Phosphodiesterase-5 inhibitors are some oral vasodilators that have been examined in patients suffering from IPF as well as COPD, but the results are not promising. However, these drugs must be studied extensively in different groups for effective therapy except for long-term oxygen therapy, which benefits 50% COPD patients. In COPD patients, the use of oxygen can reverse the hypoxia initiated medial thickening and high PVR level. Similarly, OSA must be treated with regular Bi-level or Continuous Positive Airway Pressure. It is a non-invasive form of therapy for patients suffering from sleep apnea.
Also Read:
- Primary Pulmonary Hypertension: Who Is At Risk, Is It Serious Disease, Symptoms, Diagnosis, Treatment
- How long Do You Live with Pulmonary Hypertension?
- Is there a Cure for Pulmonary Hypertension?
- What is Secondary Pulmonary Hypertension Caused By?
- What are the Symptoms of Pulmonary Hypertension?
- What is the Prognosis of Pulmonary Hypertension?
- Pulmonary Hypertension Treatment Guidelines
