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Pulmonary hypertension and cor pulmonale

Last updated: October 16, 2024

Summarytoggle arrow icon

Pulmonary hypertension (PH) is defined by an elevated mean pulmonary arterial pressure (mPAP) > 20 mm Hg at rest. PH is divided into five groups based on the underlying causes: pulmonary arterial hypertension (PAH), left heart disease, chronic lung disease, pulmonary artery obstruction (e.g., due to chronic thromboembolic disease), and unclear multifactorial mechanisms. Over time, the increase in right ventricular pressure may result in structural changes (e.g., dilation or hypertrophy) or impaired function of the right ventricle, a cardiac condition known as cor pulmonale. While PH is often asymptomatic in the early stages, symptoms such as dyspnea on exertion, fatigue, cyanosis, and syncope appear in later stages. Echocardiograms are used as an initial noninvasive test to estimate pulmonary artery pressure and to evaluate for right ventricular dysfunction. Right heart catheterization provides a definite diagnosis by measuring mPAP but is not always required. Treatment mainly consists of managing the underlying cause of PH and preventing disease progression. Patients with PAH (i.e., Group 1 PH) usually benefit from treatment with calcium channel blockers and other pulmonary vasodilators, while their benefit is unclear for other groups. In most cases, evaluation by a PH specialist and referral to specialized centers is recommended. Acute decompensated pulmonary hypertension is a high-mortality complication that can occur and is very challenging to treat, typically requiring intensive care, and in some cases, ECMO and lung transplant. Some patients develop acute or chronic cor pulmonale, which requires treatment of the underlying cause and, in some cases, acute stabilization.

This article focuses primarily on adult PH. See “Persistent pulmonary hypertension of the newborn (PPHN)” for information on PH in infants.

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Definitionstoggle arrow icon

Pulmonary arterial hypertension is a cause of pulmonary hypertension. However, not all pulmonary hypertension is caused by pulmonary arterial hypertension.

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Epidemiologytoggle arrow icon

  • PAH: more commonly affects female individuals

Epidemiological data refers to the US, unless otherwise specified.

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Etiologytoggle arrow icon

The following etiologies are grouped according to the World Health Organization (WHO) classification system for pulmonary hypertension. [7][8][9]

Pulmonary arterial hypertension (Group 1 PH)

Left heart disease (Group 2 PH)

Chronic lung diseases (Group 3 PH)

Pulmonary artery obstruction (Group 4 PH) [8]

  • Chronic thromboembolic pulmonary hypertension (CTEPH): Chronic thromboembolic occlusion of the pulmonary vessels
    • Recurrent microthrombi narrow the cross-sectional area of pulmonary vessels.
    • Affected individuals are at high risk for pulmonary embolism.
  • Other causes of pulmonary artery (PA) obstruction: extrinsic compression by mediastinal tumors or masses, arteritis involving PAs, congenital PA stenoses, fibrosing mediastinitis [10]

Unclear multifactorial mechanisms (Group 5 PH)

Conditions at high risk of PH [12]

Periodic screening and monitoring for clinical features of PH is suggested for patients with any of the following:

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Pathophysiologytoggle arrow icon

Increased pressure in pulmonary circuit → ↑ right ventricular afterload dilatation and/or hypertrophy of the right heart right heart failure and arrhythmias death.

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Clinical featurestoggle arrow icon

Patients with early PH may be asymptomatic.

Clinical symptoms may be inconspicuous, especially in the early stages when symptoms of underlying diseases such as COPD may eclipse those of PH.

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Diagnosistoggle arrow icon

Approach [4][14]

Due to overlapping clinical features, PH is often diagnosed during the evaluation of more common differential diagnoses and etiologies of dyspnea, chest pain, and fatigue (e.g., COPD, CHF, cardiomyopathy, PE, OSA), or identified during screening echocardiography or cardiac catheterization (e.g., preoperative assessment).

  • Screen and monitor patients with conditions at high risk of PH for suggestive clinical features. [12]
  • If clinical suspicion is high for PH, perform transthoracic echocardiography (TTE) to noninvasively identify markers of elevated pulmonary artery pressure.
  • If TTE suggests PH and the etiology is not yet known, begin evaluation for the most common underlying causes.
    • Identify clinical evidence of left heart disease and/or chronic lung disease and consider supportive investigations (e.g., ECG, CXR, BNP, PFTs) as directed by clinical suspicion.
    • If these are inconclusive, perform a V/Q scan to evaluate for thromboembolic disease.
  • If the etiology remains unclear, TTE is equivocal, and/or severe PH is identified (see “Severity assessment”):

Right heart catheterization can typically be deferred if echocardiography strongly suggests PH, the underlying etiology is clear (e.g., COPD), and the disease is nonsevere.

CXR, ECG, and laboratory studies are not required to diagnose pulmonary hypertension, but they may support the diagnosis and help identify the underlying etiology.

Transthoracic echocardiography (TTE) [4][7]

For clinical purposes, noninvasive estimates of mPAP and its surrogate markers, pulmonary artery systolic pressure (PASP) and right ventricular systolic pressure (RVSP), are typically accurate enough to make a diagnosis of PH and guide therapy. [15]

Echocardiography can also be used to screen patients at high risk for early features of pulmonary hypertension.

Right heart catheterization [1][4]

Obtain right heart catheterization in consultation with a PH specialist to ensure that individual patient-specific questions are addressed.

ECG [20]

Chest x-ray [14][21]

Chest x-ray findings may help to support the diagnosis of PH. [21]

Investigations of the underlying cause

Consider adding the following based on clinical suspicion of the underlying etiology:

If PH is not explained by left heart disease or chronic lung disease, perform a V/Q scan to exclude CTEPH. [7]

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Treatmenttoggle arrow icon

Approach

Therapy should be initiated early before irreversible changes in the pulmonary vessels occur.

Pulmonary vasodilators are not typically beneficial for patients with Group 2 PH (left heart disease) or Group 3 PH (chronic lung disease).

Severity assessment

WHO functional class for PH (WHO-FC) [23]

The WHO-FC system for pulmonary hypertension is widely used to help guide therapy. [12][24]

  • WHO-FC I: No limitations in physical activity; no significant symptoms during most regular ADLs and IADLs
  • WHO-FC II: Slightly limited physical activity; no rest symptoms, but some symptoms during IADLs
  • WHO-FC III: Noticeably limited physical activity; consistent symptoms during basic ADLs
  • WHO-FC IV: Severely limited physical activity; frequent and/or progressive symptoms with almost any activity or even at rest

High-risk features [24]

The presence of any of the following features typically warrants admission to a PAH specialty center for evaluation and treatment. Stabilization in an ICU setting may be required in some cases.

  • Rapidly progressing symptoms
  • Unclear PH etiology
  • Thromboembolic disease
  • Severe PH (e.g., WHO-FC III-IV)
  • Significantly elevated NT-proBNP
  • RV dysfunction
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Acute decompensated pulmonary hypertensiontoggle arrow icon

All patients

Respiratory support [26][27]

Do not attempt to intubate or mechanically ventilate patients with acute decompensated PH without guidance from specialists in critical care and pulmonary hypertension.

Hemodynamic support [26]

Consult a PH specialist to guide therapy and tailor treatment to individual needs.

Management of acute decompensated PH is extremely challenging and should take place in a specialized center whenever possible. Consult a PAH specialist immediately for any issues with IV prostacyclin pumps. [29]

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Long-term managementtoggle arrow icon

Consider individualized treatment based on the underlying condition and patient characteristics under the guidance of an appropriate specialist (e.g., cardiology, pulmonology). Calcium channel blockers and other pulmonary vasodilators are the mainstay of treatment for Group I PH (i.e., PAH), while treatment of the underlying cause is the primary focus for the other WHO PH groups.

Supportive care [24][30][31]

Overdiuresis may reduce right ventricular preload, resulting in decreased cardiac output and subsequent complications, e.g., prerenal failure.

Patients who have a normal oxygen saturation at rest may desaturate with exercise or while sleeping; perform exercise and nocturnal oximetry and treat accordingly.

Group 1 PH: PAH [12][34]

Refer all patients to a specialist PAH center for assessment and vasoreactivity testing prior to starting pulmonary vasodilator therapy aimed at decreasing pulmonary vascular resistance.

Overview of specific pulmonary vasodilator agents
Agents Clinical applications Mechanism of action Adverse effects Contraindications Interactions

Endothelin receptor antagonists (e.g., bosentan, macitentan, ambrisentan) [35]

Phosphodiesterase-5 inhibitors (e.g., sildenafil)
Prostacyclin analogs (iloprost, treprostinil)
  • Jaw pain
  • Facial or generalized flushing
  • None [36]
Synthetic prostacyclin (epoprostenol) [37]

Group 2 PH: Left-sided heart disease [7][14]

Group 3 PH: Chronic lung disease [7][14]

Group 4 PH: PA obstruction

Group 5 PH: Multifactorial diseases [41]

  • Direct initial therapy at the underlying cause of PH.
  • Consider pulmonary vasodilator therapy on a case-by-case basis.
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Cor pulmonaletoggle arrow icon

Definition [42]

Altered structure (i.e., hypertrophy, dilation) or impaired function of the right ventricle due to pulmonary hypertension resulting from a primary disorder of the respiratory or pulmonary artery system

Cor pulmonale is also known as pulmonary heart disease because it is caused by right ventricular dysfunction resulting from lung disease, not cardiac disease. [22]

Acute cor pulmonale [22]

Chronic cor pulmonale [22]

Diagnostics [42]

Treatment

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Special patient groupstoggle arrow icon

PH and pregnancy [33][44]

Contraception [33][45][46]

The CDC offers an app to guide contraceptive method selection based on the US Medical Eligibility Criteria for Contraceptive Use and the US Selected Practice Recommendations for Contraceptive Use. See “Tips and Links.”

Due to a high risk of thromboembolism, contraceptives containing estrogen are contraindicated in patients with severe PH. [45][47]

Planning pregnancy [33][44]

Pregnancy is not recommended in individuals with PAH due to high risk of maternal mortality. Recommendations for individuals with other causes of PH are based on an individualized risk assessment. [12][33][44]

During pregnancy [33][44]

Refer all patients to an obstetrician specializing in complex pregnancies and a cardiologist specializing in PH for multidisciplinary care. If possible, refer patients to a PH specialty center. [12]

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