Pulmonary Hypertension

What is Pulmonary Hypertension?

Pulmonary Hypertension is a rare disease spectrum that occurs due to increased pressures particularly in the lung vasculature. It is defined as mean Pulmonary Artery Pressure of more than 25mmHg or systolic Pulmonary Artery pressure more than 36mmHg.

What are all the Causes, Associations and Risk Factors of Pulmonary Hypertension?

Pulmonary Hypertension is one of those conditions for which, in many cases, no cause can be identified. In other words, the condition may be idiopathic

However, in other cases, the condition may be a result of certain underlying comorbid conditions like –

• Left heart diseases
• Lung diseases
• Blood clots in lung vasculature
• Connective tissue disorders
• Hematological disorders
• Liver diseases

What are the Types of Pulmonary Hypertension?

Based on the various causes, the World Health Organization (WHO) has graded the condition into the following subtypes:

GRADE 1: Pulmonary Artery Hypertension (PAH) - This group includes the idiopathic variant (cause not known), where the the disorder is a result of stiffening and remodeling of the arteries of lungs due to unknown causes.

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GRADE 2: Pulmonary Hypertension due to Left Heart diseases, which include increased systemic pressures, left sided heart pumping disorders, diseases of left sided heart valves like mitral stenosis (Heart chamber valve is narrow – resulting in built up back pressure in lung vessels) or aortic stenosis (Aorta – the main blood pipe’s from the heart - valve is narrow – resulting in built up back pressure in lung vessels)

GRADE 3: Pulmonary Hypertension due to Lung Diseases like:

• Chronic Obstructive Pulmonary Diseases (COPD) - due to long standing obstruction of lung passages like in emphysema of long standing bronchitis
• Obstructive Sleep Apnea (OSA)
• Interstitial Lung Diseases where the lung tissue is affected

GRADE 4: Chronic Thromboembolic Pulmonary Hypertension - This group includes cases where Pulmonary Hypertension is a result of blood clots or emboli in the lung vessels. Due to the clots, there is an obstruction in blood flow, leading to increased pressure.

GRADE 5: Pulmonary Hypertension due to Unclear Mechanisms- This group mainly include other causes like Thyroid disorders, Blood disorders (Sickle Cell Anemia, Hemolytic Anemia), Sarcoidosis, Glycogen Storage Disorders.

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What are the Symptoms of Pulmonary Hypertension?

The disease may initially present with symptoms like:

• Fatigue
• Shortness of breath
• Chest pain
• Fainting attacks or syncope

But as the disease progresses, it leads to right sided heart failure, and the symptoms like edemaor swelling of feet and ankles, distension of abdomen, swelling of neck veins may become more evident.

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What are the Complications of Pulmonary Hypertension?

• Cor Pulmonale – which is right sided heart failure or enlargement
• Irregular heartbeats or Arrythmias
• Hemoptysisor coughing up of blood due to bleeding in the lungs
• Thrombosis (formation of blood clots)
• Congestive Liver Disease as a result of right sided heart failure

How to Diagnose Pulmonary Hypertension?

As the disease presents with non-specific symptoms, an absolute clinical diagnosis is notpossible. Investigations are required to be performed to confirm the diagnosis of Pulmonary Hypertension.

• One of the most important investigation to screen for the disease is a Cardiac Ultrasound, also known as Echocardiography
• Lung function tests and Chest Imaging also serve as tools for diagnosing pulmonary hypertension secondary to lung diseases
• HRCT (high resolution-CT) may also play a significant role
• Other supportive investigations include ECG, V/Q (ventilation-perfusion) Scan
• However, for a definitive diagnosis, invasive techniques for monitoring of pulmonary pressures is often required. A diagnostic procedure known as Right Heart Catheterization is performed to confirm the diagnosis and assess the severity of the disease

How to Treat Pulmonary Hypertension?

Upon diagnosis, the disease warrants treatment as without treatment, the prognosis may not be favourable.

In most of the cases, the treatment of the disease is done by treating the underlying cause of the disease. For example: Oxygen therapy, Diuretics, Anticoagulants and other supportive therapy.

There is no definitive cure for Pulmonary Hypertension. However, few medications have been approved for the treatment of the disease, which mainly aim at dilating the vessels in the pulmonary vasculature. As per studies, these medications have proven to reduce morbidity and, in some cases, even the mortality.

There are three main group of medications being used:

• Prostanoids
• Endothelin Receptor Antagonists
• Phosphodiesterase 5 Inhibitors