What is Pulmonary Hypertension?
Pulmonary hypertension is a medical condition characterized by elevated blood pressure in the pulmonary artery. The pulmonary artery is a blood vessel that allows unoxygenated blood to travel to the lungs for oxygenation. Pulmonary hypertension may be idiopathic or caused by conditions such as left-sided heart failure, pulmonary embolism, chronic obstructive pulmonary disease (COPD), or obstructive sleep apnea (OSA). It may eventually lead to right-sided heart failure due to chronic hemodynamic stress on the right ventricle.
Patients often have difficulty breathing and may develop swelling in the legs. This disease is associated with a high amount of morbidity and mortality.
What Causes Pulmonary Hypertension?
Pulmonary hypertension is caused by elevated blood pressure in the pulmonary artery. In basic human physiology, blood in the peripheral veins carry unoxygenated red blood cells through the venous system, which drains into the right side of the heart. Your right ventricle then pumps blood into the lungs via the pulmonary artery. This process is critical for oxygenation of red cells and distribution of oxygen to vital organs and tissues. Once red cells are oxygenated, they then travel to the left-side of the heart and are pumped out to other organs via the left ventricle.
Low levels of oxygen in the lungs - due to chronic obstructive pulmonary disease (COPD), pulmonary embolism, or left-sided heart failure (pulmonary edema) – causes the pulmonary artery to constrict. The right ventricle now needs to pump harder to overcome the increased resistance of the pulmonary artery. Over time, the right ventricle begins remodeling and may ultimately fail. This results in a backup of fluid, causing swelling in the legs and occasionally the abdominal cavity.
Pulmonary embolism – a blood clot traveling to the pulmonary artery – can also lead to pulmonary hypertension and right heart failure. In severe cases, this condition may result in acute right ventricular dysfunction and sudden death if the embolism is large enough.
How Common is Pulmonary Hypertension?
Idiopathic pulmonary hypertension is a rare disease. In the United States, the prevalence is approximately 10 cases per million people and the incidence is almost 2 cases per million people per year. The mean age of diagnosis is 50 years and females are more often affected than males. The 3-year survival for pulmonary hypertension is estimated at 48%.
Signs and Symptoms
Symptoms and signs of pulmonary hypertension can include:
- Difficulty breathing
- Shortness of breath with exertion
- Chest pain
- Signs of right heart failure - swelling in the legs and abdominal cavity
The diagnosis of pulmonary hypertension is suggested based on symptoms and physical examination, but typically confirmed with laboratory studies. Your doctor will typically obtain a chest x-ray to evaluate for lung disease and asses cardiac size. They will also usually obtain an EKG (electrocardiogram) to evaluate the electrical activity of the heart. An ultrasound of the heart (echocardiogram) is obtained to evaluate cardiac structure and function, and get estimates of the pulmonary arterial pressure.
Acute pulmonary embolism is a medical emergency and requires hospitalization – your doctor will typically obtain a lower extremity ultrasound with Doppler studies to evaluate for deep vein thrombosis (venous blood clot in the leg). They will also usually order a CT angiogram of the chest (spiral CT) – this study evaluates the pulmonary vasculature and can identify a pulmonary embolism.
The definitive diagnosis of pulmonary arterial hypertension is made during a procedure called a right heart catheterization. During this study, your pulmonologist or cardiologist will insert a catheter into a large vein (femoral vein) in the groin and advance it until it reaches the chambers of the heart. The catheter measures pressure and other hemodynamic parameters and can accurately asses the pulmonary arterial pressure. Specialized hospitals will often perform a study called the vasoreactivity test during right heart catheterization – this can help guide doctors on the most beneficial therapy for your condition.
Commonly ordered blood tests in patients with pulmonary hypertension include a CMP (comprehensive metabolic panel), CBC (complete blood cell count), thyroid function tests (TSH, free T4), and coagulation studies (PT/INR, PTT). They will also usually check your cholesterol levels and screen for diabetes.
If you have a pulmonary embolism, they will often perform age-appropriate cancer screening (e.g., colonoscopy, mammogram) and may evaluate you for thrombotic disorders such as factor V Leiden, prothrombin mutation, and factor C and S deficiency.
Pulmonary Hypertension Treatment
Pulmonary hypertension is treated with various medical therapies depending on the cause of the condition. Patients that have fluid retention and volume overload typically benefit from diuretic therapy such as Lasix (Furosemide) or Bumex (Bumetanide). Patients with pulmonary embolism usually require treatment with anticoagulant therapy such as Coumadin (Warfarin), Xarelto (Rivaroxaban), Eliquis (Apixaban), or Pradaxa (Dabigatran). Individuals with low oxygen levels (hypoxemia) often need supplemental oxygen therapy.
Advanced treatment typically includes oral agents such as:
- Endothelin receptor antagonists
- Phosphodiesterase inhibitors such as Revatio (Sildenafil) or Adcirca (Tadalafil)
- Guanylate cyclase stimulants such as Adempas (riociguat)
- Oral prostacyclin pathway agonists such as Uptravi (selexipag)
Severe cases may require treatment with one of the following agents:
- Veletri (intravenous epoprostenol)
- Ventavis (inhaled iloprost)
- Simonneau G, Gatzoulis MA, Adatia I, et al. Updated clinical classification of pulmonary hypertension. J Am Coll Cardiol 2013; 62:D34. - https://www.ncbi.nlm.nih.gov/pubmed/24355639
- Badesch DB, Champion HC, Sanchez MA, et al. Diagnosis and assessment of pulmonary arterial hypertension. J Am Coll Cardiol 2009; 54:S55. - https://www.ncbi.nlm.nih.gov/pubmed/19555859
- Brown LM, Chen H, Halpern S, et al. Delay in recognition of pulmonary arterial hypertension: factors identified from the REVEAL Registry. Chest 2011; 140:19. - https://www.ncbi.nlm.nih.gov/pubmed/21393391
The above information is an educational aid only. It is not intended as medical advice for individual conditions or treatments. Talk to your doctor, nurse or pharmacist before following any medical regimen to see if it is safe and effective for you.