- Also known as pulmonary heart disease
- Characterized by structural alteration and dysfunction of the right ventricle (RV) caused by primary lung disease
- Can be acute or chronic:
- Acute cor pulmonale is most commonly caused by massive pulmonary embolism.
- Chronic cor pulmonale has a slow and progressive course resulting from worsening lung disease.
- Chronic lung disease with cor pulmonale indicates a poor prognosis.
Etiology and Epidemiology
- Cor pulmonale develops from increased right-sided filling pressures from long-term pulmonary hypertension (PH) associated with lung disease.
- Pulmonary hypertension is defined as:
- Increased blood pressure in pulmonary arteries
- Mean pulmonary arterial pressure of > 20 mm Hg (at rest, measured by right heart catheterization; normal = 14–20 mm Hg)
- For pre-capillary PH (disease confined to pulmonary arterial bed), criteria include pulmonary vascular resistance (PVR) of ≥ 3 Wood units).
- PH Classification (based on the 6th World Symposium of Pulmonary Hypertension proceedings):
- Group 1: Pulmonary arterial hypertension
- Group 2: PH due to left heart disease
- Group 3: PH due to lung disease and/or hypoxia
- Obstructive lung disease
- Restrictive lung disease
- Mixed obstructive/restrictive pattern
- Hypoxia (without lung disease)
- Developmental lung disorders
- Group 4: PH due to pulmonary artery obstructions
- Group 5: PH with unclear and/or multifactorial mechanisms
- RV dysfunction resulting from left-sided heart disease and congenital heart disease (group 2 PH) is not cor pulmonale.
|Primary lung disease||Diseases causing chronic hypoxia||Primary pulmonary vascular disease|
- Prevalence: limited data; right heart catheterization is not regularly performed for patients at risk
- Cor pulmonale: 6%–7% of all types of adult heart disease in the United States
- Half of the cases in North America are due to chronic obstructive pulmonary disease (COPD).
- Hypoxic pulmonary vasoconstriction
- To limit blood flow to hypoxic alveoli, low oxygen leads to pulmonary vasoconstriction, diverting blood to the better-ventilated alveoli.
- Changes in vascular mediators:
- ↑ Endothelin-1 (vasoconstrictor, smooth muscle proliferation)
- ↓ Endothelial nitric oxide synthase production: ↓ nitric oxide (vasodilator)
- ↓ Prostacyclin (vasodilator)
- Changes in ion channels:
- Chronic hypoxia reduces expression of potassium channels, increases intracellular calcium ⇒ pulmonary artery muscle contraction
- Pulmonary vascular remodeling
- Vascular alterations occur: neomuscularization of arterioles, intimal thickening, medial hypertrophy
- Inflammation and effects of cigarette smoking are potential mechanisms, as COPD-afflicted patients without hypoxemia have also been found to have endothelial dysfunction in pulmonary arteries.
- Above factors lead to increased pulmonary vascular resistance.
- As resistance increases, as does pulmonary artery pressure and, eventually, RV afterload.
- RV adapts to slowly increasing pulmonary artery pressure initially by dilation; leads to hypertrophy.
- Consequent effect is RV dysfunction and failure.
- RV hypertrophy does not occur with acute cor pulmonale.
- Dyspnea: caused by the underlying pulmonary disease and resulting cor pulmonale
- Chest pain: from increased oxygen demand and increased stress on the RV
- Syncope: inability to increase cardiac output with exertion or exercise
- Peripheral edema and increased abdominal girth: from right-sided heart failure and hepatic congestion
- Anorexia, nausea/vomiting, right upper quadrant pain: from hepatic congestion
- Signs of high right-sided filling pressures:
- RV heave
- Elevated jugular venous pressure
- Prominent V waves due to tricuspid regurgitation (jugular vein exam)
- Signs of hepatic congestion from right-sided heart failure:
- Hepatomegaly and/or pulsatile liver
- Lower-extremity edema
- Signs of hypoxemia:
- Increased respiratory rate
- Lungs: depends on underlying pulmonary disease
- Heart: accentuated P2, blowing holosystolic murmur at the left lower sternal border (tricuspid regurgitation murmur), and S3 gallop
Right heart catheterization
- Gold standard to confirm pulmonary hypertension, but not required in all patients
- Indications affected by:
- Severity of PH
- Potential for PH–specific treatment
- Life expectancy of patient
- Possibility of lung transplantation
- Results: mean pulmonary arterial pressure (mPAP) ≥ 20 mm Hg
- Initial test of choice
- RV enlargement (dilation and/or hypertrophy)
- Paradoxical movement of interventricular septum
- The septum is shifted toward the left ventricle, resulting in flattening of the ventricular septum during systole.
- Increased pulmonary artery systolic pressure
- Tricuspid regurgitation with a high-velocity regurgitant jet by Doppler
- Rules out left-sided heart failure
- Arterial blood gases: possible hypoxia ± hypercarbia and acidosis depending on degree of lung disease
- Elevated B-type natriuretic peptide (BNP) and N-terminal BNP
- CBC may show ↑ hemoglobin, ↑ hematocrit (from secondary erythrocytosis caused by hypoxia)
- P pulmonale
- Right axis deviation, right ventricular hypertrophy
- Central pulmonary artery and hilar enlargement
- Cardiomegaly (from RV enlargement)
- Changes consistent with underlying pulmonary disease
Pulmonary function test
- Shows obstructive and/or restrictive defects depending on underlying lung diseases
Chest computed tomography (CT) scan
- High-resolution: signs of interstitial lung disease or emphysema
- Angiogram: acute pulmonary embolism in the case of acute cor pulmonale; enlarged pulmonary artery
- Preferred initial test for chronic thromboembolism
- Greater sensitivity for chronic pulmonary thromboembolism than CT angiogram
Cardiac magnetic resonance imaging (MRI)
- Not routinely used but shows increased RV size
Management is first focused on the underlying cause of cor pulmonale.
- Smoking cessation
- Oxygen therapy:
- Only treatment that slows down progression of PH in COPD
- Relieves pulmonary vasoconstriction, thereby improving cardiac output and tissue perfusion
- PaO2 ≤ 55 mm Hg or oxygen saturation < 88% in general
- PaO2 ≤ 59 mm Hg or oxygen saturation ≤ 89% for patients with cor pulmonale, right heart failure, or hematocrit > 55%
- For chronic right heart failure or elevated RV filling pressures: diuretics (but monitor for volume depletion)
- For primary pulmonary arterial hypertension or group 1 PH:
- Calcium channel blockers (leads to pulmonary artery vasodilation), prostaglandin analogs, endothelin-receptor antagonists, phosphodiesterase-5 (PDE-5) inhibitors
- These medications have limited benefit in group 3 PH and in some cases may be harmful.
- Treatment of venous thromboembolism: anticoagulants
- Surgical management:
- COPD patients with hematocrit ≥ 65%: phlebotomy
- Surgical embolectomy in massive pulmonary embolism with acute cor pulmonale (if thrombolysis fails or is contraindicated)
- Lung ± heart transplantation: for patients who failed therapy
- Elwing, J.; Panos, R. (2008). Pulmonary hypertension associated with COPD. Int J Chron Obstruct Pulmon Dis. 3(1), 55–70. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2528217/
- Garrison, D.; Pendela, V.; Memon, J. (2020). Cor Pulmonale. https://www.ncbi.nlm.nih.gov/books/NBK430739/
- Klings, E.; Mandel, J.; King, T. & Finlay, G. (Eds.). (2019). Pulmonary hypertension due to lung disease and/or hypoxemia (group 3 pulmonary hypertension): Epidemiology, pathogenesis and diagnostic evaluation in adults. UpToDate. Retrieved Aug 15, 2020, from https://www.uptodate.com/contents/pulmonary-hypertension-due-to-lung-disease-and-or-hypoxemia-group-3-pulmonary-hypertension-epidemiology-pathogenesis-and-diagnostic-evaluation-in-adults
- Leong, D.; Ooi, H. (Ed). (2017). Cor pulmonale. Medscape. https://emedicine.medscape.com/article/154062-overview
- Ryu, J.; Frantz, R.; King, T; Mandel, J. & Finlay, G. (Eds.). (2020). Pulmonary hypertension due to lung disease and/or hypoxemia (group 3 pulmonary hypertension): Treatment and prognosis. UpToDate. Retrieved Aug 15, 2020, from https://www.uptodate.com/contents/pulmonary-hypertension-due-to-lung-disease-and-or-hypoxemia-group-3-pulmonary-hypertension-treatment-and-prognosis