Pulmonary hypertension is a disorder where the blood flow that leaves the right side of the heart faces an increased resistance (pressure).
Normally blood flows from the right side of the heart into the pulmonary arteries and smaller blood vessels in the lungs. The blood vessels have muscles in their walls that can relax or contract to allow more or less blood flow to enter.
In pulmonary hypertension, the blood vessels of the lungs have an increased amount of muscle in the walls. This causes a higher resistance in the lungs. The right side of the heart then has to work harder to pump blood to the lungs. The right side of the heart will enlarge and thicken in response to this extra work. With time, the extra work placed on the right side of the heart can cause it to fail.
Pulmonary hypertension may be genetic, be due to another disease (secondary), or have no obvious cause. Secondary pulmonary hypertension may occur in congenital heart disease, forms of lung disease, blood disorders, or connective tissue diseases.
Signs and Symptoms
The most common symptoms of pulmonary hypertension are related to breathing trouble and activity tolerance. They include:
- Progressive shortness of breath (especially with activity)
- Hyperventilation (breathing harder and faster)
- Fatigue (tiring easily)
- Fainting spells
- Lightheadedness or dizziness
- Coughing up blood
These symptoms may occur all at once or progress over a period of time. A patient’s cardiologist or pulmonologist will check for these symptoms during routine office visits. If any new symptoms develop, patients should call their doctor right away.
A physical exam of patients with pulmonary hypertension may show:
- Abnormal and / or louder heart sounds
- Bulging neck veins
- Swelling of the legs and hands due to fluid retention
- Enlarged liver
All of these signs are related to the right side of the heart working harder to pump blood into the high resistance in the lungs.
An electrocardiogram is performed to see if there is enlargement of the right side of the heart.
A chest X-ray may show enlargement of the size of the heart and is often a good way to follow the patient's heart size over time.
An echocardiogram, or ultrasound of the heart, is done initially and is often used to follow the progression of the disease. An echocardiogram examines the structure, function (how well the heart squeezes) and the pressure on the right side.
A cardiac magnetic resonance imaging (MRI) uses a powerful magnetic field to assess heart size and how well the heart is functioning.
A six-minute walk test is used to evaluate the exercise capacity and the response to therapy. During this test, an oxygen saturation monitor (pulse ox) is placed on the side of the head (temple), and the patient walks along the measured course at their own pace for six minutes.
An exercise (stress) test is used to measure how well the heart and lungs work during exercise on a stationary bike or treadmill.
The best way to make the diagnosis of pulmonary hypertension is a cardiac catheterization. This will measure the pressures on the right side of the heart and the resistance of the blood vessels in the lungs. Various medicines may be used during a cardiac catheterization to see if the blood vessels in the lungs will relax in response to them. This may lower the pressures in the lungs and can help guide therapy.
There are now many treatments that have been found to relieve some of the symptoms and slow the progression of disease. Unfortunately, there is no cure for pulmonary hypertension but due to these treatments the long term prognosis is much better than even five years ago.
- Oxygen: can be used at home and often helps with breathing issues. It is also known to relax the muscles in the arteries of the lungs, which will lower the pressures in the pulmonary arteries.
- Diuretics: drugs used to get rid of excess fluid in the body and reduce the amount of work on the heart.
- Calcium channel blockers (CCB): drugs that relax the muscles in the blood vessel walls and help the right side of the heart work better. Although, CCBs have been proven to be effective in some patients, only a small number of patients respond to them.
- Phosphodiesterase-5 (PDE5) inhibitors: drugs that relax the blood vessels in the lungs to allow blood to flow through more easily. This class of drugs is often used in combination with other drugs to lower pulmonary artery pressures.
- Endothelin receptor antagonists (ERAs): drugs that block the effect of endothelin, a substance in the walls of blood vessels that causes them to narrow. This drug also allows blood to flow through the lungs more easily. ERAs are often used in combination with PDE5 inhibitors to treat using two different methods. Patients who are on ERA therapy may have monthly blood tests to ensure safety of therapy.
- Prostacyclins: drugs that dilate the vessels in the lungs and have been shown to slow the progression of pulmonary hypertension. They are available in many forms such as by mouth, inhaled or as a chronic infusion.
- Anticoagulant therapies: reduce blood clots from forming in the pulmonary blood vessels.
It is important to see your doctor on a regular basis and report any changes in energy level, ability to exercise, or overall health. Patients should restrict themselves from competitive sports and only participate in light activity with the ability to rest when tired. If patients are on drug therapy, it is critical to take their medicine every day as instructed, not just when they feel bad. This will help prevent possible hospitalizations and overall worsening of pulmonary hypertension.
The long-term prognosis for pulmonary hypertension depends on its course, the severity of the disease at the time of diagnosis and response to therapy. Recent advances in medical therapies have had a profound impact on the outcome of pulmonary hypertension. If the disease does progress to the point that symptoms are excessively severe, some patients may be suitable for a procedure to let some blood bypass the lungs including an atrial septostomy, Pott’s shunt or lung transplantation.