4.3 - Pulmonary Hypertension Flashcards
What is pulmonary hypertension?
It is defined as an elevated mean pulmonary arterial pressure (> 25 mmHg) at rest.
What are the 5 causes of pulmonary hypertension?
PH has several etiologies and can be a progressive and fatal disease if not diagnosed and treated:
1. Increased pulmonary vascular resistance:
- Vasoconstriction due to hypoxemia and acidosis
- Loss of the vasculature that may be a result of emphysema and lung resection
- Occlusion of the pulmonary vasculature (due to pulmonary embolism)
- Relative stenosis of the pulmonary vasculature (due to vasculitis)
2. Increased pulmonary venous pressure:
- Left ventricular failure or hypertrophy
- Valvular heart disease (mitral valve stenosis and aortic valve stenosis
- Constrictive pericarditis
- 3. Increased pulmonary blood flow (left to right shunt):
4. Polycythemia (primary or secondary, possible due to hypoxemia)
5. Idiopathic pulmonary arterial hypertension seen most often in young women
What are the 2 most common causes of pulmonary hypertension?
It is most often due to left heart disease (Group II) or parenchymal lung disease (Group III). Complex origins of PH include infectious/environmental insults or comorbid conditions that “trigger” the condition in individuals susceptible due to a genetic predisposition.
Describe the WHO Group I classification for pulmonary hypertension
- Patients in this classification have PH due to pulmonary artery hypertension
- So what caused the pulmonary artery hypertension?
- Idiopathic pulmonary arterial hypertension - due to an unknown mechanism
- Drugs and toxins
- Familial pulmonary arterial hypertension
- Associated pulmonary arterial hypertension: collagen vascular disease (scleroderma), congenital shunts between systemic and pulmonary circulation, portal hypertension, HIV infection, or other disease or disorders
- Associated with venous or capillary disease
- Schistosomiasis – PH can develop in patients infected with schistosomiasis species, particularly if they have hepatosplenic involvement
Describe the WHO Group II classification for pulmonary hypertension
- Patients in this classification have PH due to their associated left heart disease. Patients in this group have elevated pulmonary pressures due to a high left arterial pressure resulting in pulmonary venous hypertension (postcapillary PH).
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So what caused their pulmonary hypertension?
- Left ventricular systolic or diastolic dysfunction
- Valvular disease (mitral or aortic stenosis)
- Constrictive pericarditis
- Left atrial myxoma
Describe the WHO Group III classification for pulmonary hypertension
- Patients in this classification have PH due to their associated lung disease or hypoxemia
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So what caused their pulmonary hypertension?
- Chronic obstructive pulmonary disease (COPD), interstitial lung disease
- Sleep-disordered breathing, alveolar hypoventilation
- Chronic exposure to high altitude
- Developmental lung abnormalities
Describe the WHO Group IV classification for pulmonary hypertension
- Patients in this classification have PH due to chronic thrombotic and/or embolic disease (Chronic thromboembolic pulmonary hypertension [CTEPH])
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So what caused their pulmonary hypertension?
- PE in the proximal or distal pulmonary arteries
- Embolization of other matter, such as tumor cells or parasites
Describe the WHO Group V classification for pulmonary hypertension
- Patients in this classification have PH due to miscellaneous, hematologic and systemic disorders
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So what caused their pulmonary hypertension?
- Myeloproliferative disorders
- Sarcoidosis
- Sickle cell disease
What is pre-capillary PH (Pulmonary Hypertension)?
PH due to a primary elevation of pressure in the pulmonary arterial system alone (pulmonary arterial hypertension [PAH]).
What is post-capillary PH (Pulmonary Hypertension)?
Post capillary PH is due to elevations of pressure in the venous and pulmonary capillary systems (pulmonary venous hypertension). You will see patients with mixed pre- and post- capillary features.
What are the signs and symptoms related to pulmonary hypertension?
- Dyspnea with exertion (most common)
- Exercise intolerance
- Exertional dizziness
- Substernal discomfort, chest pain
- LE edema
- Increased abdominal girth due to ascites
- Hoarseness due to impingement on the laryngeal nerve by the enlarging pulmonary artery
- Fatigue
- Syncope
- Palpitations
What conditions are associated with pulmonary hypertension?
CHF, OSA, connective tissue diseases, and venous thromboembolism
What physical exam findings should you anticipate/will find in a patient with pulmonary hypertension?
Your physical examination should focus on identifying underlying conditions linked to PH. Look for skin changes from scleroderma, stigmata of liver disease, clubbing (congenital heart disease) and abnormal breath sounds (parenchymal lung disease).
- Labored respirations and DOE
- Splitting of the second cardiac sound, pulmonic valve component of the second heart sound (P2) is increased in intensity
- Peripheral edema - related to right ventricular (RV) failure. The RV fails when pumping against increased pressures in the lungs. Right sided failure is called cor pulmonale.
- Ascites, distended neck veins
- RV heave
- Loud pulmonic valve
What is the purpose of laboratory/diagnostic tests for evaluating pulmonary hypertension?
The purpose of diagnostic testing is to confirm your clinical suspicion of PH, to determine the etiology, to gauge the severity of your patient’s condition to guide your treatment.
What 8 laboratory/diagnostic tests are used to diagnose PH?
1. 2D echo - usually used to diagnose pulmonary hypertension. This is your first test. It will be done with a saline injection to assess for a shunt. If a shunt is suspected, a transesophageal echocardiogram will be done to confirm.
2. Cardiac catheterization will confirm the diagnosis. Elevated mean pulmonary artery pressure with normal pulmonary capillary wedge pressure, elevated pulmonary artery systolic pressure and tricuspid regurgitation velocity
3. CXR - will show an increase in the size of the proximal pulmonary arteries, visible narrowing of the pulmonary arteries in the medial third of the lung, typically seen in emphysema. Other possible findings from comorbid diseases include interstitial infiltrates (interstitial lung disease), hyper inflated lungs (COPD, emphysema)
4. PFTs - done to assess for obstructive and restrictive ventilatory defects, Six-minute walk is done as a test of functional capacity
5. CBC & ABG - will show an increase in hemoglobin and hematocrit if hypoxemia is present, ABG: elevated arterial partial pressure of carbon dioxide (PaCO2) is an important clue for a hypoventilation syndrome
6. Pulmonary angiography – will confirm thromboembolic disease, if needed an inferior vena cava filter can be deployed at the same time
7. Cardiac MRI – investigate for cardiac anomalies that have be the cause of PH especially if a transesophageal echocardiogram is contraindicated
8. Right heart catheterization – used to investigate pulmonary hypertension. Measurements of pulmonary pressures are obtained to determine elevations and help in diagnosis.
Describe the WHO functional class I for pulmonary hypertension
- In this class there are no symptoms of pulmonary arterial hypertension with exercise or at rest. It is rare for a patient to be diagnosed while still a class I.
- Patients that are being screened because of high-risk factors for developing pulmonary hypertension, such as patients with scleroderma or family history of PAH, may rarely be diagnosed as class I.
- More often this classification is used to describe patients that have demonstrated a substantial response to therapy that were once a class II or III but have improved to a class I
Describe the WHO functional class II for pulmonary hypertension
No symptoms at rest but uncomfortable and short of breath with normal activity such as climbing a flight of stairs, grocery shopping, or making the bed.
Describe the WHO functional class III for pulmonary hypertension
May not have symptoms at rest but activities greatly limited by shortness of breath, fatigue, or near fainting. Patients in this class have a difficult time doing normal chores around the house and have to take breaks while doing activities of daily living.
Describe the WHO functional class IV for pulmonary hypertension
Symptoms at rest and severe symptoms with any activity. Patients in this class may faint especially while bending over with their heads lowered. Most patients in this class are also volume overloaded with edema in their feet and ankles from right heart failure
