Today I wanted to discuss an interesting but also potentially very dangerous condition called pulmonary hypertension. I refer to it as interesting for 3 reasons:
- Most heart disease tends to affect older people but pulmonary hypertension can affect young people as well.
- The symptoms in the early stages can be non-specific and not dramatic and therefore may not get taken as seriously by the patient or even the doctors and therefore there may be a delay of several years before a diagnosis is made.
- The treatment of this condition can be very effective if started at an early stage but if the condition is missed until that point when the symptoms are very dramatic, the prognosis can be very poor because by that time, you have missed the boat.
So I am hoping that this article may help those people who may have noticed some of the symptoms of this condition to ask for detailed assessment by a cardiologist
What is pulmonary hypertension?
In the simplest sense, it means that it is harder for the heart to pump the blood into the lungs and it is therefore diagnosed by finding evidence of a higher blood pressure in the artery (which is the pulmonary artery) that takes the blood from the heart to the lungs.
The normal pressure in the pulmonary artery is generally less than 25mmHg. If the pressures in the pulmonary artery are greater than 25mmHg then a diagnosis of pulmonary hypertension is made. The higher the pressure, the more severe the pulmonary hypertension.
Pulmonary hypertension is not a disease per se but rather the consequence of a variety of underlying disease processes (some of which I will discuss later in this video)
What are the symptoms associated with pulmonary hypertension?
The fundamental problem is difficulty in getting blood into the lungs to be oxygenated. So in the very early stages there may be no symptoms. However as the difficulty increases, the first symptoms start becoming apparent on exercise and are usually due to a lack of oxygen in the body when the body of oxygen.
Patients may notice that they are progressively more tired, weak and more breathless on doing the kind of activities that wouldn’t ordinarily have caused these symptoms. Because these symptoms may be mild, people (and their doctors) may just put them down to being unfit and ignore them. As it becomes more difficult for the heart to pump blood into the lungs, the amount that the patient can do gets less because the symptoms become more noticeable. Other symptoms that may occur include chest pain (caused because the heart is having to work so hard and has less oxygen supplying it) and even blackouts because of a lack of oxygen to the brain. Other less common symptoms include a dry cough and exercise induced nausea and vomiting.
When the pulmonary hypertension is really severe, the right heart having worked so hard with less oxygen can start tiring and weakening and this makes everything worse because there is no longer anything trying to push the blood into the lungs. This condition is called right heart failure and is very dangerous because even if you identify and treat the condition that is causing the pulmonary hypertension, the right heart will continue to remain weak. As the right heart starts weakening, the blood that would normally enter the right heart cant enter it because the blood that is already there isn’t being pumped into the lungs and therefore blood starts pooling in the legs and the abdomen and this results in progressive legs swelling and abdominal swelling and often it is these symptoms which lead the patient to seek medical help but by that time it is often at a very severe stage and the prognosis is much worse.
Why does it happen?
There are a variety of causes for pulmonary hypertension. To make it easy to understand, we need to first think of how blood moves round the body.
Normally the left side of the heart pumps blood into the body (except the lungs), the blood returns to the right side of the heart which then pumps blood into the lungs from where the blood is received by the left side of the heart which then pumps the blood to the rest of the body.
- If the left heart is weak or diseased in some way, it will not pump blood out to the body as efficiently and therefore it will be more difficult for blood from the lungs to enter the left heart which means that it is more difficult for the right heart to pump blood into the lungs and you get pulmonary hypertension. So a very common cause of pulmonary hypertension is left heart disease such as left heart weakness (cardiomyopathy) or even leaking or abnormal narrowing of the left heart valves. In this case the treatment is to address the problem with the left heart.
- If you have bad lungs for any reason then that will make it more difficult for the right heart to pump blood into the lungs. Common conditions include COPD, emphysema, chronic bronchitis, sleep apnoea and also lung fibrosis. In this situation you have to treat the lung condition to help the pulmonary hypertension.
- If you have an obstruction stopping the blood from getting into the lungs then this can cause pulmonary hypertension. This happens in people who develop recurrent lung clots or pulmonary emboli and this is why anyone with unexplained pulmonary hypertension should have a lung scan to actively exclude lung clots. If lung clots are found, patients usually require life-long anticoagulation. Sometimes if there are very big lung clots it may be possible to mechanically fish them out therby relieving the obstruction and improving the pulmonary hypertension.
- There is a really interesting group of patients in whom the pulmonary hypertension occurs because of disease of the pulmonary artery itself and its branches which lead to the lungs. In these patients, the pulmonary arteries are stiffened and possibly thickened and narrowed and thereby restrict blood from getting through the lungs. This can happen because the patient has some sort of connective tissue disorder or it may happen as a disease in its own right with no other underlying aetiology (and in this setting it can be seen in very young patients too) These patients are termed as having pulmonary artery hypertension (and the ones who have no underlying aetiology are termed as having primary pulmonary hypertension) and this is a particularly important group to identify because in these patients there are new medications and treatments which have revolutionised the prognosis. Remember in all the other types I have mentioned, the treatment is to treat the underlying cause but in this group medications which open up these arteries can make a huge difference to the patient. Such medications include Viagra, bosentan and prostacycline analogues.
How do you you diagnose it?
You have to measure the pressure in the pulmonary artery. This is best done by using passing a pressure measuring catheter through one of the veins in the leg all the way into the right heart and then into the pulmonary artery and measuring the pressure. This is the gold standard. The problem is that this is a very specialist and invasive investigation and therefore you cant offer it to everyone who complains of a bit of breathlessness and tiredness.
An easier and non-invasive way to measure the pulmonary artery pressure is by using echocardiography or cardiac ultrasound. You can visualise the right heart quite easily on the ultrasound and often patients who have pulmonary hypertension have a bit of leaking of their heart valves because of the back pressure. The velocity of the leak is directly proportional to the pressure driving the leak and therefore we can use Doppler to measure the velocity of the leak and then this can be put in a mathematic formula to derive a pressure difference and this way you can get a reasonably reliable indication of the pulmonary artery pressure.
What is the treatment?
Once you have identified that there is pulmonary hypertension, the next thing is to look for the cause and therefore an assessment of the left heart, testing the lungs for underlying lung disease or blood clots and a search for connective tissue disease is important. Where there is an underlying cause, treatment of the underlying cause improves the pulmonary hypertension. Patients who have a problem with their pulmonary arteries can benefit from vasodilator therapy and should be seen in a pulmonary hypertension centre. The prognosis of these patients 10-15 years ago was only 30-40% at 3 years. Now it has gone up to 85-90% because of these new medications and therefore it has become more important that we are all aware of this condition and seek specialist advice at an early stage
Here is a video I recently recorded on the subject of pulmonary hypertension
I hope you have found this useful. I would love to hear your comments. If you get a chance please consider sharing the video and subscribing to my youtube channel Yorkcardiology.
Keywords: Pulmonary hypertension; primary pulmonary hypertension; cor pulmonale; right heart failure