Pulmonary hypertension

What is it?

The NHLBI defines it as "a condition that affects the blood vessels in your lungs, and occurs when the blood pressure in your lungs is higher than normal". It makes the heart work harder than usual to pump blood to the lungs, which may damage the heart and cause shortness of breath, chest pain and dizziness. The NHS describes it as a serious condition that can damage the right side of the heart, and MedlinePlus states that this extra strain can eventually lead to heart failure.

The five groups according to the NHLBI: (1) pulmonary arterial hypertension (PAH); (2) caused by left-sided heart disease; (3) caused by lung disease and/or low oxygen (hypoxia); (4) caused by blockages in the pulmonary arteries, including chronic thromboembolic pulmonary hypertension (CTEPH); (5) of unknown and/or multiple causes. The NHS also mentions a rare type in newborns, persistent pulmonary hypertension of the newborn (PPHN).

The figures according to the NHLBI: about 1% of people worldwide have it, and more than 50% of cases of pulmonary arterial hypertension worldwide have no known cause. In the United States the most common type is that caused by left-sided heart disease such as left heart failure.

Causes

According to the NHLBI, when pressure in the pulmonary arteries rises, these arteries narrow or become blocked, so the heart works harder and may be damaged over time. MedlinePlus states that it may occur on its own or because of another condition.

The causative conditions according to the NHLBI and MedlinePlus: left heart disease such as left heart failure (which may result from high blood pressure in the body or coronary artery disease), and congenital heart defects; lung diseases such as chronic obstructive pulmonary disease, interstitial lung disease, emphysema and sleep apnoea; and other conditions such as liver disease, sickle cell anaemia, blood clots in the lungs, and connective tissue disorders such as scleroderma.

The NHS details on its causes page: causes of PAH include scleroderma, congenital heart defects (a hole in the heart), portal hypertension, HIV infection and some medicines or drugs, and it may be of unknown cause or (rarely) inherited; left heart disease includes problems of the mitral or aortic valve or the left ventricle; clots include chronic thromboembolic hypertension and pulmonary embolism. Less common causes include sarcoidosis and vasculitis, thyroid diseases and glycogen storage disease, sickle cell anaemia and thalassaemia, chronic kidney disease, and compression of the lung vessels (for example by tumours).

Risk factors

Risk factors according to the NHLBI: age (usually diagnosed between 30 and 60 and the risk rises with age), sex (more common in women than in men), family history and genetics (Down syndrome, congenital heart disease, Gaucher disease, and a family history of clots), environment (exposure to asbestos and some parasitic infections), lifestyle (smoking and illicit drug use), and some medicines prescribed to treat cancer and depression. MedlinePlus lists almost the same.

Having one of the causative conditions (left heart disease, lung disease, pulmonary clots, sickle cell anaemia) raises the likelihood (NHLBI). Do not stop any prescribed medicine because of this list; discuss it with your doctor.

Symptoms

Symptoms according to the NHLBI: chest pain, cough (dry or with blood), shortness of breath, dizziness that may lead to fainting, nausea and vomiting, hoarseness, severe tiredness, swelling of the abdomen, legs or feet, weakness, and wheezing. MedlinePlus and the NHS add palpitations.

Symptoms worsen over time: in the early stages shortness of breath may appear only on exertion, and then becomes more frequent as the disease progresses (NHLBI). The NHS states that symptoms often get worse during exercise, and that some people with PAH may have no symptoms until advanced stages.

Symptoms are sometimes hard to recognise because they resemble those of other conditions, so diagnosis may be delayed for years (NHLBI).

How is it diagnosed?

The doctor starts with the medical history and clinical examination, and may refer you to a lung specialist or a heart and vascular specialist (NHLBI). The examination includes measuring blood oxygen with a finger sensor, feeling the liver, listening to the heart (murmur or arrhythmia) and lungs, examining the neck veins, looking for swelling of the abdomen or legs, and measuring blood pressure.

The most common tests to measure pulmonary artery pressure are cardiac catheterisation and echocardiography (NHLBI). According to the NHLBI: normal pressure is between 11 and 20 mmHg, and it is considered abnormal if it reaches 25 mmHg or above by catheterisation, or 35 to 40 mmHg or above by echo. The NHS explains that echo estimates the pressure and assesses the pumping of both sides of the heart, and that right heart catheterisation (a thin flexible tube inserted through a vein in the neck, arm or upper thigh into the pulmonary artery) confirms the diagnosis by measuring pressure accurately. These are general figures, and the doctor interprets your result.

Other tests: blood tests looking for clots, heart strain or anaemia (NHLBI) and ruling out thyroid and liver disease (NHS); cardiac MRI for detailed pictures of its structure and function; chest X-ray for the size and shape of the heart and surrounding vessels (and the NHS mentions an enlarged heart or lung scarring); and electrocardiogram for changes in electrical activity (NHLBI). The NHS adds lung function tests, exercise tests and a ventilation–perfusion scan to look for clots. Additional tests may be requested to determine the underlying cause (NHLBI).

Severity: the NHS states that the condition is usually classed into 4 categories by tolerance of physical activity, from no symptoms with ordinary activity to symptoms at rest that worsen with any activity. The NHS cautions that reaching a correct diagnosis may take time.

Treatment

The treatment categories usually used are listed here; this is not a prescription. The doctor chooses the plan according to each person's condition; do not change any medicine or dose without a specialist.

The doctor decides the treatment plan according to the cause of the disease if it is known (NHLBI). The NHLBI, MedlinePlus and NHS state that there is often no cure, but there are ways to prevent symptoms from worsening and to ease them.

Medicine categories mentioned (the doctor chooses what suits your condition): anticoagulants (blood thinners), diuretics to remove excess fluid, digoxin to help the heart muscle pump, vasodilators including calcium channel blockers, endothelin receptor antagonists and phosphodiesterase type 5 inhibitors (NHLBI, NHS, MedlinePlus). The NHS also mentions prostaglandins, soluble guanylate cyclase stimulators and a biological therapy. Do not start, stop or change any medicine without the doctor.

Other treatments and procedures: oxygen therapy (including at home) when blood oxygen falls; surgical pulmonary endarterectomy to remove clots from the lung vessels; balloon pulmonary angioplasty for those who are not suitable for that surgery; balloon atrial septostomy to create a small opening between the two chambers of the heart to improve blood flow; and lung or heart–lung transplant in severe cases (NHLBI, NHS, MedlinePlus).

Treating underlying conditions according to the NHLBI: blood pressure medicines, blood transfusion or drug treatment for sickle cell anaemia, repair of heart valves, and iron supplements for anaemia; and the NHS states that the causative condition is treated first. Even so, the NHLBI advises a heart-healthy diet with less salt, and physical activity that may be part of a supervised pulmonary rehabilitation programme.

Follow-up

Follow-up according to the NHLBI may include: a 6-minute walk test, blood tests (haemoglobin, iron, salts, and kidney, liver and thyroid function), cardiac catheterisation, cardiac MRI, chest X-rays, echocardiography, electrocardiogram, and lung function tests. The doctor decides which are needed and when.

The NHLBI advises getting the recommended vaccines, which often include the pneumococcal vaccine and the annual flu vaccine.

Complications

Serious complications according to the NHLBI: anaemia, heart rhythm disorders, blood clots, bleeding in the lung, heart failure, liver damage, fluid collecting around the heart, and pregnancy complications. MedlinePlus states that the extra strain on the heart may eventually lead to heart failure.

The NHS points out that the outlook varies according to the cause, the timing of diagnosis, the severity of symptoms and the presence of other diseases.

Prevention

This page does not cover prevention in detail. The NHLBI lists smoking, illicit drug use and asbestos exposure among the risk factors, and advises treating related conditions such as chronic obstructive pulmonary disease, heart disease and sleep apnoea.

Living with it

According to the NHLBI: ask your doctor about the right level of physical activity before starting any exercise programme, avoid high altitudes where possible, discuss air travel plans with your doctor, and keep to a heart-healthy lifestyle.

Pregnancy: the NHLBI advises speaking to the doctor when planning pregnancy because the risk of pregnancy complications rises.

Support: taking part in support groups, counselling and education helps manage daily activities and improve quality of life (NHLBI).

Common questions