PH is definitely more common than previously believed. However, it is not clear exactly how many Canadians might suffer from PH. This is because of several reasons:

• There are few studies that have been done in Canada
• There are many kinds of PH
• Many patients with early or mild PH may not have symptoms, and as a result, have not yet been diagnosed

PH experts have estimated the number of Canadians who might have PH based on studies from the US and Europe:

• The number of Canadians who may suffer from PAH (one of the most severe types of PH) presently is probably between 2,000 and 10,000
• Another 250-500 Canadians will develop PAH every year
• There is clearly a much larger number of Canadians who suffer from other types of PH, and who develop PH every year

Yes, PH can be due to infections in some patients. However, an infection is not the cause of PH in most patients.

Specific types of infection can cause PH:

• Infection of the bowels and liver by the parasite, schistosomiasis, is a very common cause of PH around the world, but is very rare in Canada
• Infection with HIV, the AIDS virus, can cause PAH
• Infection with hepatitis viruses (Hepatitis B and C viruses) causes chronic hepatitis and cirrhosis of the liver, which can lead to PAH

Yes, in many patients, PH can be due to a disease of the heart.

In some types of heart disease, blood backs up into the lungs, causing PH:

• Heart failure, due to previous heart attacks, high blood pressure (also known as systemic hypertension), or diabetes
• Diseases of the valves of the left-side of the heart, specifically the mitral valve and aortic valve

Another important type of heart disease is due to defects of the heart present at birth (also known as congenital heart disease), such as:

• atrial septal defect (ASD)
• ventricular septal defect (VSD)
  

Yes, in many patients, PH can be due to a disease of the lungs. PH is usually seen when the lung disease is severe. In patients with lung disease, low oxygen levels in the blood usually cause PH.

However, in most patients with lung disease, PH is usually mild.

Diseases of the lungs that can cause PH include:

• Emphysema of the lungs due to smoking
• Scarring (also known as fibrosis) of the lungs
• Recurrent or multiple blood clots in the lungs (also known as pulmonary embolism)
• Breathing problems at night that cause low oxygen levels in the blood, for example sleep apnea

Yes, in some patients, PH can be due to blood clots in the lungs (also known as pulmonary embolism). After pulmonary embolism, up to 4% of patients may develop PH within 2 years.

All patients diagnosed with PH should be assessed for the presence of blood clots in the lungs. This is because of several reasons:

• Pulmonary embolism is a common cause of PH
• Treatment with blood thinners (also known as anti-coagulants) can greatly decrease the risk of recurrent pulmonary embolism
• In some patients with PH due to pulmonary embolism, surgery to remove the blood clots (also known as pulmonary thromboendarterectomy) may be very effective in treating the PH

In many patients, PH can be associated with a number of other medical conditions:

• Connective tissue diseases, such as scleroderma (also known as CREST), or systemic lupus erythematosus (SLE)
• Infection with HIV, the AIDS virus
• Severe liver disease, such as cirrhosis
• Diseases of the blood, like sickle-cell disease and thalassemia
• History of taking certain appetite-suppressant medications for weight loss (known as anorexigens)

.Yes, some medications can cause PH.

Patients who have taken weight loss medications (also known as appetite-suppressant medications or anorexigens) have a higher risk of PAH. These medications include:

• Aminorex
• Fenfluramine (Ponderal, Pondamin)
• Dexfenfluramine (Redux)
• Phentermine (Ionamin)
• Mazindol

Patients who have abused recreational drugs are at higher risk for PH. These drugs include:

• Cocaine

Some medications used to treat cancer (also known as chemotherapy) have been reported to cause PH. These medications include:

• Bleomycin
• Busulfan
• Carmustine (BCNU)
• Interferon-alpha
• Interleukin-2
• Lomustine (CCNU)
• Mitomycin C
• Nitrosoureas

Many other uncommon medications may sometimes cause PH. These medications include:

• Cyclosporine
• Hydralazine
• L-tryptophan
• Protamine

No, pregnancy is not believed to cause PH.

In pregnancy, most healthy, normal women will experience some degrees of difficulty breathing, fatigue, and swelling of feet or ankles. This is often perfectly normal and does not necessarily mean you have PH.

Pregnancy increases the risk of blood clots in the lung (also known as pulmonary embolism) which can lead to PH.

In women who already have certain types of PH, they may first notice symptoms of PH during pregnancy. This includes:

• IPAH (previously known as PPH)
• PAH associated with defects of the heart present at birth (also known as congenital heart disease)
• PH due to pulmonary embolism

In women already diagnosed with PH, pregnancy can be extremely dangerous. PH often worsens during the pregnancy, and often leads to death of the mother. It is strongly recommended that a woman with PH not become pregnant.

This is a question that only your doctor can address specifically for you.

You may have PH if you have any of the following symptoms:

• Unexplained difficulty breathing or shortness of breath (also known as dyspnea)
• Chest pain
• Inability to exercise
• Faintness or passing out (also known as syncope)

You may have PH if you have a family history of PH in a close relative (parents, siblings, children).

You may have PH if you already have a condition of the heart or lungs or another medical condition that can cause PH. These include:

• Heart disease, such a heart failure
• Lung disease such as emphysema
• A history of pulmonary embolism
• Connective tissue diseases such as scleroderma (also known as CREST)
• Infection with HIV, the AIDS virus
• Severe liver disease, such as cirrhosis
• Use of certain medications, such as appetite-suppressant medications for weight loss (also known as anorexigens)

This is a question that only your doctor can address specifically for you

In a small number of patients, PH can be inherited. In these patients, there is often a family history of PH in a close relative (for example, parents, siblings, children). It is likely that these patients inherited a defective (also known as mutant) gene that causes PH. These patients are said to have familial PAH (FPAH).

In a small number of patients, there is no clear cause for PH. In such patients, PH is labeled idiopathic PAH (IPAH; previously known as primary PH = PPH).

In many patients, PH is the result of a condition of the heart or lungs or another medical condition that can cause PH. These include:

• Heart disease, such a heart failure
• Lung disease such as emphysema
• Blood clots in the lungs (also known as pulmonary embolism)
• Connective tissue diseases such as scleroderma (also known as CREST)
• Infection with HIV, the AIDS virus
• Severe liver disease, such as cirrhosis
• Use of certain medications, such as appetite-suppressant medications for weight loss (also known as anorexigens)

The symptoms of PH include:

• difficulty breathing or shortness of breath (also known as dyspnea)
• fatigue or tiredness
• swelling of feet and ankles (also known as edema), and possibly swelling of the belly or abdomen (also known as ascites)
• chest pain, typically felt as a heaviness, pressure, or tightness in the center of the chest (also known as angina). This usually occurs on activity or exertion
• feelings of faintness or lightheadedness, feeling like passing out, or actually losing consciousness (also known as syncope); this usually occurs on activity or exertion, but may occur on straining or coughing
• a rapid, forceful, or irregular heartbeat (also known as palpitations)
• other less common symptoms include cough, hoarseness of your voice, coughing up blood (also known as hemoptysis)

The narrowing of the pulmonary arteries leads to the abnormally high blood pressure in the pulmonary arteries, which is called PH.

The narrowing of the pulmonary arteries means the right ventricle (RV = lower chamber on the right side) of the heart has to work harder to pump blood through the lungs. Because the RV of the heart has to work harder in PH, it is the RV that eventually gets weak, leading to RV failure, a type of heart failure. Heart failure means the heart cannot pump enough blood for the body’s needs. There is reduced blood flow to the organs of the body. Reduced blood flow causes the symptoms of difficulty breathing, fatigue, chest pain, and faintness.

If PH is not treated, the RV of the heart will eventually fail in many PH patients, which may lead to death.

In most PH patients, PH gets worse if left untreated. In some PH patients, PH may remain stable over many months or years.

Whether PH gets worse in an individual patient depends on many factors. These include:

• The cause of PH
• The severity of PH
• The age of a patient
• The general health of a patient
• The presence of other conditions of the heart, lungs, or body
• What PH treatment is available to a patient
• How a patient responds to PH treatment

Only your doctor can address the risk of dying from PH in your particular case.

PH is a serious disease, which can be life-threatening. If left untreated, many PH patients will die of PH.

For example, in patients with certain types of PAH (the most severe type of PH), patients live on average 2-3 years, if left untreated. These patients include:

• Patients with idiopathic PAH (IPAH; previously known as PPH)
• Patients with PAH due to connective tissue disease (such as scleroderma)

Some patients with PAH live for many years, even if left untreated.

• Patients with PAH due to congenital heart disease

Some types of PH can be prevented by early diagnosis and treatment of other medical conditions: For example:

• In patients with lung disease, diagnosis of low oxygen levels in the blood and appropriate treatment with oxygen may prevent PH
• In patients born with defects of the heart (also known as congenital heart disease), early diagnosis of the defect, such as during childhood, and surgical repair of the defect may prevent PH in the future
• In patients with pulmonary embolism, effective treatment with blood thinners (also known as anti-coagulants) may prevent PH

In many other types of PH, there is presently no way to prevent PH. These types of PH include:

• Idiopathic IPAH (previously known as PPH)
• Familial or inherited PAH (FPAH)
• PAH associated with connective tissue disease (such as scleroderma), HIV infection, cirrhosis of the liver

There are many causes of PH. Sorting out (also known as classifying) and labeling different types of PH is very important for many reasons:

• It helps doctors and scientists communicate better
• It helps doctors understand how different types of PH are related
• It helps doctors make a clearer diagnosis of PH
• It makes the treatment of PH clearer
• It helps doctors better understand how a patient might respond to a treatment

In the past, PH was simply classified into primary or secondary:

• Primary PH (PPH). An older term. In a small number of PH patients, there is no known cause for PH. These patients were said to have PPH. In the current 2003 Venice classification, these patients would be diagnosed with idiopathic PAH (IPAH)
• Secondary PH (SPH). An older term. SPH indicated that there was a known cause for PH, such as heart disease (for example, heart failure), lung disease (for example, emphysema), or a general medical condition (such as cirrhosis of the liver)

The most commonly used classification system today is the 2003 World Health Organization (WHO) Venice PH Classification System. Groups in the 2003 Venice classification system include:

• WHO Group 1: PAH = pulmonary arterial hypertension. A newer term, which specifically indicates that PH is due to narrowing of the pulmonary arteries of the lungs. PAH is a broad category which includes many patients with different types of PAH:
  • IPAH = idiopathic PAH. A newer term for the old term, PPH. In a small number of PH patients, there is no known cause for PH. They are said to have IPAH
  • FPAH = familial PAH. In some PAH patients, PAH was inherited from their parents. There is often a history of PAH in other close members of the patient’s family (for example, parents, sibilings, or children)
  • CTD-PAH. PAH associated with connective tissue disease (CTD), such as scleroderma
  • HIV-PAH. PAH associated with HIV infection
  • CHD-PAH. PAH due to heart defects present at birth (also known as congenital heart disease = CHD)
    
• WHO Group II: PVH = pulmonary venous hypertension. PH due to disease of the left-side of the heart, including the left ventricle (LV; lower left chamber) of the heart, left atrium (LA; upper left chamber), or disease of the mitral valve or aortic valve on the left-side of the heart
  
• WHO Group III: PH due to pulmonary arteries being blocked by blood clots (also known as pulmonary embolism). This type of PH is often referred to as chronic thromboembolic PH (CTEPH). In rare patients, PH can be due to other types of material blocking pulmonary arteries, including cancer cells or eggs of the parasite infection, schistosomiasis.
  
• WHO Group IV: PH due to lung disease and low blood oxygen levels. These lung diseases include emphysema of the lung (usually due to smoking), scarring (also known as fibrosis) of the lung, or breathing problems during sleep (for example, sleep apnea)
  
• WHO Group V: PH due to various other rare lung conditions and other rare general medical conditions