Pulmonary Hypertension Overview

Pulmonary Hypertension (PH) Overview

• PH is defined as elevated blood pressure in the pulmonary arteries.
• The condition results in increased resistance to blood flow in the lungs.
• At rest, normal pulmonary artery pressure is about 12-16 mmHg for mean pulmonary arterial pressure (mPAP).
• Pulmonary hypertension is often determined when mean pulmonary artery pressure is greater than 20 mmHg at rest, which is measured through right heart catheterization.

Classification of PH

• Group 1 (PAH) includes idiopathic, heritable, and drug/toxin-induced cases.
• Group 2 PH is due to left heart disease.
• Group 3 PH is associated with lung diseases.
• Group 4 PH is due to blood clots in the lungs.
• Group 5 PH involves unclear or multifactorial mechanisms.

Symptoms of PH

• Dyspnea, or shortness of breath, occurs especially during physical activity.
• Fatigue is caused by decreased oxygen delivery to tissues.
• Chest pain results from strain on the heart.
• Other symptoms depend on the cause of PH.

Signs of PH

• Jugular Venous Distension (JVD) arises from visible swelling of the jugular veins in the neck, often indicating elevated pressure in the right side of the heart.
• Hepatomegaly is enlargement of the liver that is a result of congestion in the hepatic veins due to right-sided heart strain.
• Ascites is a build-up of fluid in the abdominal cavity is a result of increased pressure in the veins leading to the liver.
• Peripheral Edema is swelling, especially in the ankles and legs that happens because of fluid retention caused by impaired circulation.

Local Signs PH

• Clubbing of Fingers involves abnormal enlargement of the fingertips with nail changes caused by chronic oxygen deprivation.
• Right Ventricular Heave or Lift is a visible or palpable pulsation of the chest wall and indicates increased workload on the right side of the heart.
• Splitting of S2.
• Murmurs can involve pulmonary regurgitation, tricuspid regurgitation, or functional pulmonary stenosis.

Complications of PH

• Right Ventricular Hypertrophy (RVH) is enlargement of the right ventricle because of increased workload.
• Right Heart Failure is a consequence of progressive RVH.
• Arrhythmias are an increased risk of irregular heart rhythms.
• Hemoptysis is coughing up blood caused by increased pressure in pulmonary vessels.

Investigations to Diagnose PH

• Blood Tests involve BNP (B-type natriuretic peptide) to detect elevated levels that may indicate heart failure, and Blood Gas Analysis to assess oxygen and carbon dioxide levels.
• Imaging Studies include Echocardiogram (Echo) for initial assessments of pulmonary artery pressure and heart function, and Electrocardiogram (ECG or EKG) to detect abnormal heart rhythms and signs of right ventricular hypertrophy.
• A Chest X-ray Reveals signs of PH like enlarged pulmonary arteries.
• CT or MRI Scans help identify structural abnormalities and rule out other causes.
• Pulmonary Function Tests use Spirometry assesses lung function and eliminate obstructive lung diseases.
• Ventilation/Perfusion (V/Q) Scan is important for diagnosing chronic thromboembolic pulmonary hypertension (CTEPH).
• Right Heart Catheterization (RHC) is definitive to measure pressures directly in the heart chambers to confirm PH diagnosis, and to assess severity in providing detailed information on the PH cases.
• Genetic Testing is performed for Heritable Forms where a genetic component is suspected.
• Pulmonary Angiography is an invasive test only occasionally used for detailed imaging of pulmonary arteries.

Treatment of PH

• Vasodilators help relax and dilate pulmonary blood vessels with drugs like prostacyclin analogs (epoprostenol, treprostinil), endothelin receptor antagonists (bosentan, ambrisentan), and phosphodiesterase-5 inhibitors (sildenafil, tadalafil).
• Calcium Channel Blockers are used in some cases, especially in responders to vasodilator testing.
• Anticoagulants prevent blood clots.
• Diuretics manage fluid retention and relieve symptoms like peripheral edema and ascites.
• Oxygen Therapy improves oxygen levels in the blood and reduce strain on the heart.
• Exercise Training uses tailored exercise programs to improve physical capacity and overall well-being.
• Supportive Measures involve nutritional support to ensure adequate nutrition, and psychological support by counseling and support groups.

Interventional Procedures for PH

• Pulmonary Thrombo-endarterectomy (PTE) which surgically removes of chronic blood clots in the lungs in cases of chronic thromboembolic pulmonary hypertension (CTEPH).
• Lung Transplantation is considered for advanced cases when other treatments are ineffective.
• Management of Underlying Conditions is used to treat the underlying causes from connective tissue diseases or chronic respiratory conditions.