A Group of Disorders…
Pulmonary hypertension (PH) has traditionally been defined as a mean pulmonary arterial pressure (mPAP) exceeding 25 mmHg; however, this definition was recently amended to 20 mmHg and above. Normally, the pulmonary circulation is under low pressure with low resistance; normal pulmonary artery (PA) pressure is ~15 mmHg.
More broadly, PH is a complex, multifactorial group of disorders, which are classified into 5 groups:
Key point: It’s important to distinguish pulmonary arterial hypertension (PAH) from pulmonary hypertension (PH); the former refers to group 1 in the above classification whereas the latter is an umbrella term (i.e., when all 5 groups are discussed collectively, the term PH is used.)
PH most often develops as an advanced feature of left heart disease (60%), chronic hypoxic lung disease (20%), or a combination of chronic heart and lung disease (10%).
Without effective therapy, PH leads to progressive RV failure with escalating symptoms—death often occurs within 3-5 years!
Recognizing PH can be difficult because its symptoms are non-specific. The most common initial symptoms are exertional dyspnea, lethargy, and fatigue.
- Symptoms of RV failure, which develop as PH progresses, include exertional chest pain, exertional syncope, edema, and weight gain, among others.
Studies of patients with PAH provide additional perspective on symptoms:
- Dyspnea on exertion (86%)
- Fatigue (26%)
- Chest pain (22%)
- Edema (20%)
- Presyncope or syncope (17%)
- Palpitations (12%)
Uncommon symptoms of PH include cough, hemoptysis, and hoarseness. Ortner’s syndrome is hoarseness that occurs when enlarged vascular structures (such as an enlarged PA in the presence of PH) compress the left laryngeal nerve.
Specific features on exam may suggest PH:
- Left parasternal lift (i.e., RV heave)
- Palpable P2
- Loud P2
- Pansystolic murmur of tricuspid regurgitation
- Diastolic murmur of pulmonary regurgitation
- Advanced disease: elevated JVP, hepatomegaly, ascites, peripheral edema, cool extremities
Delayed diagnosis of PAH is common, and it is often confused with other diagnoses such as HF or even asthma. Nevertheless, there are some features that stand out about PAH:
If PH is suspected, the initial test of choice is echocardiography while confirmatory testing typically requires cardiac catheterization; however, most patients initially undergo other studies.
The 2015 ESC/ERS Guidelines for the diagnosis and treatment of pulmonary hypertension offer insight on the range of studies commonly performed:
- ECG (more likely to be abnormal in severe PH)
- Potential findings: P pulmonale, RAD, RVH, RV strain, RBBB, QTc prolongation
- Normal ECG does not exclude PH
- CXR / HRCT
- Potential findings: evidence of lung disease or venous congestion, PA dilatation with attenuation of peripheral vessels, RA/RV enlargement, pleural effusions (late finding)
- Normal CXR does not exclude PH
- Pulmonary function testing (PFTs) / ABG
- Potential findings: evidence of lung disease, low DLCO, abnormal PaO2 and PaCO2
- Other: overnight oximetry, polysomnography, 6-minute walk test, V/Q scan
- 70-80% of patients with PAH have nocturnal hypoxemia and central sleep apnea
- V/Q scan should be performed in patients with unexplained PH to look for chronic thromboembolic disease
Key point: Blood tests are not useful in diagnosing PH, but are needed to identify the etiology of some forms of PH (see classification groups above) as well as the presence of end organ damage.
General algorithm for PH work-up:
Further Reading & Listening!
- The Curbsiders: Episodes on Pulmonary Hypertension and Pulmonary Hypertension Update
- Galiè et al. An overview of the 6th World Symposium on Pulmonary Hypertension. Eur Respir J. 2019
- Galiè et al; ESC Scientific Document Group. 2015 ESC/ERS Guidelines for the diagnosis and treatment of pulmonary hypertension. Eur Heart J. 2016
- Simonneau et al. Haemodynamic definitions and updated clinical classification of pulmonary hypertension. Eur Respir J. 2019
Blog post based on Med-Peds Forum talk by Rebecca Raymond-Kolker, PGY2