New Delhi: Pulmonary arterial hypertension is a lung disorder in which the arteries that carry blood from the heart to the lungs become narrowed, making it difficult for blood to flow through the vessels.
As a result, the blood pressure in these arteries — called pulmonary arteries — rises far above normal levels. This abnormally high pressure strains the right ventricle of the heart, causing it to expand in size.
Overworked and enlarged, the right ventricle gradually becomes weaker and loses its ability to pump enough blood to the lungs. This could lead to the development of right heart failure.
“Pulmonary hypertension occurs in individuals of all ages, races, and ethnic backgrounds, although it is much more common in young adults and is approximately twice as common in women as in men,” says Dr Ravindranath Reddy, Sr Consultant Interventional Cardiologist, BGS Gleneagles Global Hospitals.
-Symptoms of pulmonary hypertension
Symptoms of pulmonary hypertension do not usually occur until the condition has progressed. The first symptom of pulmonary hypertension is usually shortness of breath with everyday activities, such as climbing stairs. Fatigue, dizziness and fainting spells also can be symptoms.
Swelling in the ankles, abdomen or legs, bluish lips and skin, and chest pain may occur as strain on the heart increases. Symptoms range in severity and a given patient may not have all of the symptoms. In more advanced stages of the disease, even minimal activity will produce some of the symptoms.
-Causes of pulmonary hypertension
• Drugs- dexfenfluramine and phentermine
• Chronic lung diseases
• Chronic liver diseases
• Autoimmune diseases
• Congenital and acquired heart diseases
• Thromboembolic diseases
• Obesity, sleep apnea
• Idiopathic, genetic inheritance
-Diagnosis of pulmonary hypertension
It can often be hard to detect PAH in a routine clinical examination, even if the disease has progressed. Symptoms of PAH are not unique and may be confused with many other diseases that cause a lack of oxygen in the blood. The diagnosis of PAH is also one of exclusion, meaning that PAH is only diagnosed when other causes of pulmonary hypertension have been ruled out and there seems to be no known cause of the hypertension.
The tests that are commonly performed to diagnose PAH and rule out other diseases are blood tests, pulmonary function tests, X-rays of the chest, electrocardiography (ECG), and the “6-minute walk test”, which essentially measures how far an individual can walk in that time period.
Ultimately, the majority of subjects undergo echocardiographic testing, followed by confirmation by cardiac catheterization with and without vasodilator testing. Pulmonary angiogram looks for blood clot blockages in the pulmonary arteries and other lung parenchymal conditions
Heritable PAH is confirmed if two or more family members have PAH or if a BMPR2 gene mutation is identified in the affected person. Molecular genetic testing is available for mutations in the BMPR2 gene, but should only be performed in concert with genetic counseling.
The prognosis of severe pulmonary arterial hypertension has an untreated median survival of 2-3 years from time of diagnosis, with the cause of death usually being right ventricular failure. But recent advances in treatment options have significantly improved both morbidity and mortality.
Several medications have been approved by the US Food and Drug Administration (FDA) for the treatment of PAH. These medications can be broadly broken down into four categories described below.
oThe orphan drug epoprostenol sodium for injection or prostacycline has been approved as a standard long-term treatment of individuals with severe PAH. This drug is administered by intravenous infusion through a permanent ambulatory in-dwelling central venous catheter. Iloprostfor the treatment of PAH. The treatment is inhaled through the mouth with the assistance of a special nebulizer.
•Endothelin Receptor Antagonists
oBosentan and Ambrisentan have been approved by the FDA for treatment of PAH.
oSildenafil, a phosphodiesterase type 5(PDE5) inhibitor is also used to treat PAH.
oTadalafil is a once-daily phosphodiesterase type 5 (PDE-5) inhibitor, shown to improve the patient’s ability to exercise.
• Supportive Therapies
oDrugs that cause widening of blood vessels (vasodilators) and lessen blood pressure may also be used to treat PAH. In some PAH cases, calcium channel blockers (e,g, nifedipine and diltiazem) are used as vasodilators.
oOther treatments such as anticoagulants, diuretics, and oxygen are used to treat PAH as supportive therapies. Anticoagulants, such as warfarin, are drugs that prevent blood clots from forming. Studies have shown that treatment with anticoagulants improves the long-term prognosis in individuals with idiopathic and heritable forms of PAH.
•Pulmonary thrombo endarterectomy: If present, blood clots in the pulmonary artery may be surgically removed to improve blood flow and lung function.
•Lung Transplantation: Currently, this is the only cure for pulmonary hypertension. Transplantation is reserved for advanced pulmonary hypertension that does not respond to medical therapy.
•Heart/lung transplantation: This type of double organ transplant is very rare but is necessary for all patients who have combined lung and left heart failure.
In severe cases of PAH, a heart-lung, single lung or double lung transplant may be recommended. (ANI)