What happens in PH?
- In PH, the lung’s arteries gradually narrow, which severely impedes blood to flow normally from the heart through the lungs.
- This means the heart has to work harder than normal to push the blood through the lungs. Over time, the heart weakens and cannot keep up so that blood flow decreases.
- Eventually, the heart becomes so weak that it cannot pump enough blood to meet the demands of the body, even at rest, which leads to the debilitating symptoms of heart failure such as: shortness of breath at rest or during minimal activity (for example, climbing two flights of stairs), tiredness, swelling of the legs and stomach, and palpitations (abnormal heartbeats).
People of all ages, races and ethnic backgrounds can be diagnosed with pulmonary hypertension (PH). However, certain risk factors make some people more likely to get the disease. Risk factors include:
- Family history – if two or more family members have the disease or if a family member is known to have a PH-causing gene mutation
- Obesity and obstructive sleep apnea – in isolation, obesity is not a risk factor. However, if obesity is combined with obstructive sleep apnea (meaning that oxygen levels fall while a person is sleeping), mild PH may occur.
- Gender – idiopathic and familial PH (IPAH and FPAH) are at least 2.5 times more common in women than in men
- Pregnancy – while pregnancy does not make someone more susceptible to pulmonary hypertension, women who already have PH and become pregnant have a much higher risk of mortality. Women with PH, who have not yet been diagnosed, may experience more severe symptoms (than previously) and quicker disease progression, this is why sometimes PH diagnosis occurs during pregnancy.
- Altitude – living at a high altitude for years can make you more susceptible to PH. Travel at high altitudes can aggravate PH. High altitudes can also cause other pulmonary problems, such as pulmonary edema, in some people.
- Other diseases – other diseases, including congenital heart disease, lung disease, liver disease and connective tissue disorders like scleroderma and lupus, can lead to the development of pulmonary hypertension.
- Drugs and toxins - certain drugs, such as methamphetamines and the diet drug “fenphen” are known to cause pulmonary hypertension.
- Pulmonary hypertension may be caused by other conditions.
- PH Can also be idiopathic, meaning it has no known cause
Types of Pulmonary Hypertension
Often both the acronyms PH and PAH are used. What’s the difference?
Pulmonary hypertension, or PH, is the general term used to describe high blood pressure in the lung from any cause.
Pulmonary Arterial Hypertension, or PAH, is high blood pressure in the pulmonary arteries from diseases that affect the small vessels of the lung, causing them to narrow and impede blood flow.
Oral Treatment options
Endothelin Receptor Antagonists (ERAs) help prevent blood vessels from narrowing.
- Ambrisentan (Volibris®) – approved in Canada in 2008
- Bosentan (Tracleer®) – approved in Canada in 2001
- Macitentan (Opsumit®) – approved in Canada in 2013
Phosphodiesterase inhibitors (PDE 5 inhibitors) allow the lungs to produce more of its own natural vasodilators.
- Sildenafil (Revatio®, Viagra®) – approved in Canada in 2006
- Tadalafil (AdCirca®, Cialis®) – approved in Canada in 2010
Soluble guanylate cyclase stimulators (sCG stimulators) increase the sensitivity of sGC to endogenous nitric oxide (NO), they also directly stimulate the receptor to mimic the action of NO.
- Riociguat (Adempas®) – approved in Canada in 2013 for treatment of non-operative or residual post-operative CTEPH (WHO class IV) and 2014 for PAH (WHO class I)
IP receptor agonists and prostanoids are vasodilators that also have antiproliferative and antiplatelet properties. Prostacyclin is under-produced in patients with pulmonary hypertension.
Oral IP receptor agonist – stimulates the IP prostacyclin receptor to cause vasodilation
- Selexipag (Uptravi®) – approved in Canada in 2016
- Oral Treprostinil (Orenitram®) – not approved in Canada (approved in USA in 2013)
Inhaled treatment options (prostacyclins)
Inhaled Treatment Options, such as prostacyclins, relieve shortness of breath.
- Iloprost (Ventavis®) – Not approved in Canada but available in the US and Europe
- Inhaled Treprostinil (Tyvaso®) – Not approved in Canada but available in the US
Intravenous treatment options (prostacyclins)
Intravenous treatment options open up the blood vessels and help ease symptoms of PH, including chest pain and shortness of breath
- Epoprostenol (Flolan®) – approved in Canada in 1997
- Intravenous Treprostinil (Remodulin®) – approved in Canada in 2005
- Room temperature stable Epoprostenol (Caripul®, Veletri® - in USA and Europe) – approved in Canada in 2013
Subcutaneous treatment options (prostacyclins)
Subcutaneous treatment options are delivered through a portable infusion pump to open up the blood vessels and ease the symptoms of PH.
- Subcutaneous Treprostinil (Remodulin®) – approved in Canada in 2002
Although all of the above-mentioned medications help to alleviate the symptoms of PH and slow its progression, they do not provide a cure. As the disease progresses, treating physicians prescribe the available treatments alone or in combination to help alleviate the symptoms and slow progression. Once a combination of treatments is no longer effective, lung transplantation may be considered.
While this list illustrates current treatment options, the ideal treatment pathway for a patient may only be decided upon by their PH-treating specialist. Please see your specialist to discuss the ideal treatment pathway for you.