Cor Pulmonale – Causes, Symptoms, Diagnosis, Treatment and Ongoing care

Basics

Description

  • Enlargement and subsequent dysfunction and failure of the right ventricle (RV) in the presence of pulmonary arterial hypertension secondary to abnormalities of the lungs, thorax, pulmonary ventilation or circulation
  • May occur in acute or chronic setting:
    • Acute: Rapid increase of pulmonary arterial pressure causing RV overload and resulting dysfunction/failure
    • Chronic: Progressive hypertrophy and dilation of RV over months to years, with eventual dysfunction/failure

Epidemiology

  • Approximately, 6–7% of all types of adult heart disease in US
  • Between 10% and 30% of heart failure admissions in the US are the result of cor pulmonale (1).

Incidence

Difficult to assess. Best estimate is 1/10,000–3/10,000 per year (2).

Prevalence

Difficult to assess. Best estimate is 2/1,000–6/1,000 (2).

Risk Factors

  • Acute cor pulmonale is most commonly caused by massive pulmonary embolism (PE):
    • Risk factors associated with PE include:
      • Vessel injury
      • Stasis
      • Hypercoagulable states
  • Chronic cor pulmonale is most commonly caused by COPD and/or pulmonary arterial hypertension (PAH).
    • Risk factors associated with COPD and/or PAH include:
      • Tobacco use
      • Living at high altitudes
      • Industrial exposures such as asbestos
      • Alpha-1-antitrypsin deficiency
      • Connective tissue disease

General Prevention

  • Prevention of pulmonary embolism via deep venous thrombosis prophylaxis when necessary
  • Early detection and timely management of COPD to delay its progression
  • Management of underlying disease, including aggressive correction of hypoxia and acidosis, that may contribute to worsening pulmonary hypertension

Pathophysiology

  • Acute: A sudden event, such as large pulmonary embolism, increases resistance to blood flow in the pulmonary vasculature, causing a quick and significant increase of pressure proximally. The RV is unable to overcome this pressure, leading to low cardiac output and RV failure.
  • Chronic: PAH develops from many possible etiologies, although predominantly from alveolar hypoxia. The RV is initially able to compensate for this increased pressure through concentric hypertrophy. However, worsening pulmonary hypertension eventually overcomes the RV’s accommodative abilities, leading to dilation of the RV. This results in both systolic and diastolic dysfunction, causing reduced cardiac output and right-sided heart failure.

Etiology

  • Lung disease: COPD including emphysema and chronic bronchitis (80–90%) (3), cystic fibrosis, restrictive and interstitial lung disease, including scleroderma and sarcoidosis, pulmonary thromboembolism, tumor emboli, idiopathic pulmonary arterial hypertension
  • Hematological abnormalities: Sickle cell anemia, polycythemia vera
  • Neuromuscular disease: Amyotrophic lateral sclerosis, myasthenia gravis, Guillain-Barré syndrome, polio, spinal cord injuries
  • Disorders of ventilator control: Primary central hypoventilation, sleep apnea syndromes
  • Thoracic cage deformities: Kyphoscoliosis
  • Collagen vascular disease
  • Left ventricular failure is NOT considered a cause of cor pulmonale.

Commonly Associated Conditions

Pulmonary arterial hypertension (PAH): Classically defined as the presence of a resting mean pulmonary artery pressure (PAP) >20 mm Hg, though some sources define as >25 mm Hg at rest and >30 mm Hg with exercise

Pulmonary hypertension, Chronic obstructive pulmonary disease, Heart failure, Cardiovascular Disorders, Hypertension, massive pulmonary embolism, deep venous thrombosis, acute cor pulmonale, alpha 1 antitrypsin deficiency, thrombosis prophylaxis,

Diagnosis

History

  • Dyspnea, orthopnea
  • Fatigue, lethargy, syncope
  • Cyanosis, pallor, diaphoresis
  • Pleuritic chest pain, cough, hemoptysis
  • Exertional angina
  • Hoarseness secondary to compression of the left recurrent laryngeal nerve by enlarged pulmonary vessels
  • Anorexia and/or right upper quadrant discomfort from hepatic congestion
  • Cardiovascular collapse, shock, and/or cardiac arrest may occur in acute setting or advanced chronic setting.

Physical Exam

  • Peripheral edema is the most common sign of right heart failure (RHF), though it is nonspecific.
  • Tachypnea, wheeze
  • Increased intensity of pulmonic component of 2nd heart sound (P2)
  • Splitting of S2 over the cardiac apex with inspiration
  • Audible S3 or S4
  • Pansystolic murmur heard best at right midsternal border increasing with inspiration, consistent with tricuspid regurgitation (typically a late sign).
  • Early diastolic murmur heard best at left upper sternal border, consistent with pulmonary regurgitation.
  • Right ventricular heave
  • Jugular venous distension with inspiration (Kussmaul sign)
  • Prominent a and v waves on jugular venous pulse tracing
  • Hepatomegaly
  • Signs of DVT, such as tenderness or unilateral swelling, may or may not be present.

Diagnostic Tests & Interpretation

ECG (poor sensitivity; up to 67% patients will have normal findings) (1):

  • Rightward P-wave axis deviation
  • Peaked P waves anteriorly and in inferior leads (i.e., “P pulmonale”)
  • S1S2S3 pattern, or S1Q3T3, inverted pattern (McGinn-White pattern)
  • RV hypertrophy (high specificity, low sensitivity)
  • Right bundle-branch block
  • Low-voltage QRS

Lab

Initial lab tests

  • CBC and serum chemistries may be obtained to rule out other conditions:
    • Lab findings such as polycythemia and hypercapnia may be present due to COPD.
    • LFTs may be elevated due to hepatic congestion secondary to RV failure.
  • Pulmonary function testing may show airflow obstruction with reduced PO2, or other findings associated with COPD.
  • Arterial blood gas, indicated for acute respiratory distress, may show hypercapnic acidosis and hypoxemia.
  • BNP and cardiac troponins may be elevated secondary to RV stretch.

Imaging

  • Chest x-ray:
    • Cardiomegaly
    • Increased width of right descending pulmonary artery
    • Left main pulmonary artery prominence below the aortic knob
  • 2-dimensional echocardiogram:
    • RV mid-wall hypokinesis/akinesis plus normokinesis/hyperkinesis of RV apex (McConnell sign) are associated with acute cor pulmonale caused by acute pulmonary embolism.
    • RV dilatation and/or hypertrophy may be indicative of chronic cor pulmonale.
    • Doppler echocardiography with saline contrast to estimate tricuspid regurgitation is the most reliable noninvasive estimation of pulmonary artery pressure (PAP).
  • Spiral CT scan of chest:
    • Most accurate modality for diagnosing emphysema and interstitial lung disease
    • Test of choice for assessment of acute pulmonary embolism
  • V/Q scan may be used to assess for pulmonary embolism in acute cor pulmonale.
  • MRI commonly used, as it can characterize right ventricular size, mass morphology, and gross function

Diagnostic Procedures/Surgery

  • Right heart catheterization is the gold standard for quantitation of ventricular and pulmonary pressures, and exclusion of congenital heart disease as etiology. Right heart catheterization is also recommended to assess vasoreactivity prior to implementing calcium channel blocker therapy.
  • Pulmonary function tests should be performed in patients with a suggestive history of underlying lung disease and in those with normal cardiac function.

Differential Diagnosis

  • Right-sided heart failure secondary to left-sided heart failure
  • Right-sided cardiomyopathy, ischemic or nonischemic
  • Tricuspid valvulopathy
  • Severe congenital pulmonary hypertension secondary to congenital heart disease with left-to-right shunting, most frequently from unrepaired nonrestrictive ventricular septal defect (VSD)

Treatment

Reduce disease burden via oxygenation, preservation of cardiac function, and attenuation of PAH (4).

Medication

  • Oxygenation:
    • Oxygen:
      • Long-term continuous oxygen therapy improves the survival of hypoxemic patients with COPD and cor pulmonale.
      • All patients with pulmonary hypertension whose PaO2 is consistently <55 mm Hg or saturation ≤88% at rest, during sleep, or with ambulation should be prescribed oxygen to keep O2 >90 mm Hg (5)[A].
  • Preservation of cardiac function:
    • Diuretics: Decrease RV filling pressures; also improves peripheral edema secondary to right heart failure:
      • Furosemide: Starting at 20–80 mg p.o./IV, titrate and increase dose per diuresis.
      • Excessive volume depletion should be avoided.
      • Monitor closely for metabolic alkalosis, as this may suppress ventilatory drive and contribute to hypoxia.
    • Cardiac glycosides:
      • Impact of digoxin on cor pulmonale alone is unclear
      • Digoxin may be appropriate in the presence of co-existent left ventricular systolic failure.
      • Digoxin may also be appropriate in the presence of atrial fibrillation as adjunct for rate control.
  • Amelioration of PAH:
    • Calcium channel blockers (CCB) (4):
      • May be used as adjunctive therapy in those with low-to-moderate disease
      • Vasodilator therapy to reduce pulmonary vascular resistance has been shown to be effective in a small subset of patients (10%).
      • Vasoreactivity trial should be attempted with short-acting vasodilator at cardiac catheterization to determine likelihood of response. Reduction of >20% PAP without reduction of cardiac output should prompt adding CCB such as nifedipine, diltiazem, amlodipine to treatment regimen.
      • Repeat vasoreactivity trial via cardiac catheterization is recommended at 3–6 months following initiation of CCB therapy to assess sustained response. For nonsustained response, discontinue CCB and pursue alternative medications (6).
    • For nonresponse or unsustained response to CCB, treatment with phosphodiesterase inhibitors, endothelin receptor antagonists, and/or prostanoids may be appropriate based on World Health Organization (WHO) classification (6):
      • WHO Class I: Supportive therapy.
      • WHO Class II: Monotherapy is recommended with either phosphodiesterase inhibitor or endothelin receptor antagonist.
      • WHO Class III: Combination therapy may be used with phosphodiesterase inhibitor, endothelin receptor antagonist, or prostanoids. There is currently little randomized data on which combination is most efficacious (7).
      • WHO Class IV: Epoprostenol IV is 1st-line therapy in critically ill patients; other classes of drugs may also be added for combination therapy.
      • Phosphodiesterase inhibitors: Vasodilates by increasing cAMP and therefore increasing nitric oxide, an endogenous vasodilator. Sildenafil, tadalafil: Endothelin receptor antagonists: Vasodilates by blocking the function of endothelin, a potent vasoconstrictor. Bosentan, Ambrisentan, Sitaxsentan.
      • Prostanoids: Vasodilates by mimicking endogenous vasodilators. Iloprost Inhaled. IV may also be used; evidence to date limited to expert opinion. Treprostinil SC. IV may also be used; evidence to date limited to expert opinion. Beraprost PO Epoprostenol IV: Currently recommended for WHO Class IV only.
    • Anticoagulation:
      • Recommended for patients with underlying thromboembolic disease
      • Recommended for patients with cor pulmonale in association with idiopathic pulmonary arterial hypertension (5)[B]
      • Use in secondary causes of PAH is widely accepted, though little supportive evidence to date (8)
      • In general, warfarin is recommended unless contraindications. Target international normalized ratio (INR) for prophylaxis is 2–3.

Additional Treatment

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General Measures

  • Treat underlying disease.
  • Supportive therapy as necessary:
    • Continuous positive airway pressure or bilevel positive airway pressure may be used for hypoxia/sleep disorders.
    • Ventilation using positive-pressure masks, negative-pressure body suits, or mechanical ventilation is suggested for patients with neuromuscular disease.
    • Phlebotomy may be indicated for severe polycythemia (hematocrit >55%).

Issues for Referral

Patients with cor pulmonale should be referred to a cardiologist or pulmonologist for expert consultation.

Surgery/Other Procedures

Moderate-to-severe disease refractory to medication may require atrioseptostomy and/or lung transplantation.

Ongoing Care

Referral of patients with PAH to a specialized center with close follow-up is strongly recommended.

Diet

Salt and fluid restriction

Patient Education

  • Smoking cessation and avoidance of exposure to secondary smoke is strongly recommended.
  • Exertional activity should be limited.
  • Pregnancy should be avoided in PAH.

Prognosis

  • Patients with cor pulmonale resulting from COPD have a greater likelihood of dying than do similar patients with COPD alone.
  • The pulmonary artery pressure (PAP) is a reliable indicator of prognosis; higher pressure is associated with worse prognosis.
  • In patients with COPD and mild disease (PAP 20–35 mm Hg), 5-year survival is 50%.

References

1. Han MK, McLaughlin VV, Criner GJ, Martinez FJ et al. Pulmonary diseases and the heart. Circulation. 2007;116:2992–3005.

2. Naeije R et al. Pulmonary hypertension and right heart failure in chronic obstructive pulmonary disease. Proc Am Thorac Soc.2005;2:20–2.

3. Weitzenblum E, Chaouat A et al. Cor pulmonale. Chron Respir Dis. 2009;6:177–85.

4. Hoeper MM et al. Drug treatment of pulmonary arterial hypertension: current and future agents. Drugs. 2005;65:1337–54.

5. Badesch DB, Abman SH, Simonneau G, et al. Medical therapy for pulmonary arterial hypertension: updated ACCP evidence-based clinical practice guidelines. Chest. 2007;131:1917–28.

6. Barst RJ, Gibbs JS, Ghofrani HA, Hoeper MM, McLaughlin VV, Rubin LJ, Sitbon O, Tapson VF, Galiè N et al. Updated evidence-based treatment algorithm in pulmonary arterial hypertension. J Am Coll Cardiol. 2009;54:S78–84.

7. Benedict N, Seybert A, Mathier MA et al. Evidence-based pharmacologic management of pulmonary arterial hypertension.Clin Ther. 2007;29:2134–53.

8. Alam S, Palevsky HI. Standard therapies for pulmonary arterial hypertension. Clin Chest Med. 2007;28:91–115, viii.

Additional Reading

See Also (Topic, Algorithm, Electronic Media Element)

Pulmonary Embolism; Chronic Obstructive Pulmonary Disease and Emphysema; Pulmonary Arterial Hypertension, Idiopathic; Congestive Heart Failure

Codes

ICD9

  • 415.0 Acute cor pulmonale
  • 416.9 Chronic pulmonary heart disease, unspecified

Snomed

  • 49584005 Acute cor pulmonale (disorder)
  • 79955004 Chronic cor pulmonale (disorder)

Clinical Pearls

  • Continuous, long-term oxygen therapy improves life expectancy and quality of life in cor pulmonale.
  • Referral of patients with PAH to a specialized center is strongly recommended.

 

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