Overview

• 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 Pulmonary Embolism Pulmonary embolism (PE) is a potentially fatal condition that occurs as a result of intraluminal obstruction of the main pulmonary artery or its branches. The causative factors include thrombi, air, amniotic fluid, and fat. In PE, gas exchange is impaired due to the decreased return of deoxygenated blood to the lungs. 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

Etiology

• Cor pulmonale develops from increased right-sided filling pressures from long-term pulmonary hypertension Pulmonary Hypertension Pulmonary hypertension (PH) or pulmonary arterial hypertension (PAH) is characterized by elevated pulmonary arterial pressure, which can lead to chronic progressive right heart failure. Pulmonary hypertension is grouped into 5 categories based on etiology, which include primary PAH, and PH due to cardiac disease, lung or hypoxic disease, chronic thromboembolic disease, and multifactorial or unclear etiologies. Pulmonary Hypertension (PH) associated with lung disease.
• Pulmonary hypertension Hypertension Hypertension, or high blood pressure, is a common disease that manifests as elevated systemic arterial pressures. Hypertension is most often asymptomatic and is found incidentally as part of a routine physical examination or during triage for an unrelated medical encounter. Hypertension is defined as:
  • Increased blood pressure in pulmonary arteries Arteries Arteries are tubular collections of cells that transport oxygenated blood and nutrients from the heart to the tissues of the body. The blood passes through the arteries in order of decreasing luminal diameter, starting in the largest artery (the aorta) and ending in the small arterioles. Arteries are classified into 3 types: large elastic arteries, medium muscular arteries, and small arteries and arterioles. 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 Hypertension Hypertension, or high blood pressure, is a common disease that manifests as elevated systemic arterial pressures. Hypertension is most often asymptomatic and is found incidentally as part of a routine physical examination or during triage for an unrelated medical encounter. 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.

Epidemiology

• 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 Chronic obstructive pulmonary disease Chronic obstructive pulmonary disease (COPD) is a lung disease characterized by progressive, largely irreversible airflow obstruction. The condition usually presents in middle-aged or elderly persons with a history of cigarette smoking. Signs and symptoms include prolonged expiration, wheezing, diminished breath sounds, progressive dyspnea, and chronic cough. Chronic Obstructive Pulmonary Disease (COPD) ( COPD COPD Chronic obstructive pulmonary disease (COPD) is a lung disease characterized by progressive, largely irreversible airflow obstruction. The condition usually presents in middle-aged or elderly persons with a history of cigarette smoking. Signs and symptoms include prolonged expiration, wheezing, diminished breath sounds, progressive dyspnea, and chronic cough. Chronic Obstructive Pulmonary Disease (COPD)).

Pathophysiology

• 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 COPD Chronic obstructive pulmonary disease (COPD) is a lung disease characterized by progressive, largely irreversible airflow obstruction. The condition usually presents in middle-aged or elderly persons with a history of cigarette smoking. Signs and symptoms include prolonged expiration, wheezing, diminished breath sounds, progressive dyspnea, and chronic cough. Chronic Obstructive Pulmonary Disease (COPD)-afflicted patients without hypoxemia have also been found to have endothelial dysfunction in pulmonary arteries Arteries Arteries are tubular collections of cells that transport oxygenated blood and nutrients from the heart to the tissues of the body. The blood passes through the arteries in order of decreasing luminal diameter, starting in the largest artery (the aorta) and ending in the small arterioles. Arteries are classified into 3 types: large elastic arteries, medium muscular arteries, and small arteries and arterioles. 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.

Clinical Presentation

Symptoms

• Dyspnea: caused by the underlying pulmonary disease and resulting cor pulmonale
• Chest pain Chest Pain Chest pain is one of the most common and challenging complaints that may present in an inpatient and outpatient setting. The differential diagnosis of chest pain is large and includes cardiac, gastrointestinal, pulmonary, musculoskeletal, and psychiatric etiologies. Chest Pain: from increased oxygen demand and increased stress on the RV
• Syncope Syncope Syncope is a short-term loss of consciousness and loss of postural stability followed by spontaneous return of consciousness to the previous neurologic baseline without the need for resuscitation. The condition is caused by transient interruption of cerebral blood flow that may be benign or related to a underlying life-threatening condition. Syncope: inability to increase cardiac output with exertion or exercise
• Peripheral edema Edema Edema is a condition in which excess serous fluid accumulates in the body cavity or interstitial space of connective tissues. Edema is a symptom observed in several medical conditions. It can be categorized into 2 types, namely, peripheral (in the extremities) and internal (in an organ or body cavity). Edema and increased abdominal girth: from right-sided heart failure and hepatic congestion
• Anorexia, nausea/vomiting, right upper quadrant pain: from hepatic congestion

Signs

Inspection

• Signs of high right-sided filling pressures:
  • RV heave
  • Elevated jugular venous pressure
  • Prominent V waves due to tricuspid regurgitation Tricuspid regurgitation Tricuspid regurgitation (TR) is a valvular defect that allows backflow of blood from the right ventricle to the right atrium during systole. Tricuspid regurgitation can develop through a number of cardiac conditions that cause dilation of the right ventricle and tricuspid annulus. A blowing holosystolic murmur is best heard at the left lower sternal border. Tricuspid Regurgitation (jugular vein exam)
• Signs of hepatic congestion from right-sided heart failure:
  • Hepatomegaly and/or pulsatile liver Liver The liver is the largest gland in the human body. The liver is found in the superior right quadrant of the abdomen and weighs approximately 1.5 kilograms. Its main functions are detoxification, metabolism, nutrient storage (e.g., iron and vitamins), synthesis of coagulation factors, formation of bile, filtration, and storage of blood. Liver
  • Ascites Ascites Ascites is the pathologic accumulation of fluid within the peritoneal cavity that occurs due to an osmotic and/or hydrostatic pressure imbalance secondary to portal hypertension (cirrhosis, heart failure) or non-portal hypertension (hypoalbuminemia, malignancy, infection). Ascites
  • Lower-extremity edema Edema Edema is a condition in which excess serous fluid accumulates in the body cavity or interstitial space of connective tissues. Edema is a symptom observed in several medical conditions. It can be categorized into 2 types, namely, peripheral (in the extremities) and internal (in an organ or body cavity). Edema
• Signs of hypoxemia:
  • Increased respiratory rate
  • Cyanosis
  • Clubbing

Chest auscultation

• Lungs: depends on underlying pulmonary disease
• Heart: accentuated P2, blowing holosystolic murmur at the left lower sternal border ( tricuspid regurgitation Tricuspid regurgitation Tricuspid regurgitation (TR) is a valvular defect that allows backflow of blood from the right ventricle to the right atrium during systole. Tricuspid regurgitation can develop through a number of cardiac conditions that cause dilation of the right ventricle and tricuspid annulus. A blowing holosystolic murmur is best heard at the left lower sternal border. Tricuspid Regurgitation murmur), and S3 gallop

Management

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 COPD Chronic obstructive pulmonary disease (COPD) is a lung disease characterized by progressive, largely irreversible airflow obstruction. The condition usually presents in middle-aged or elderly persons with a history of cigarette smoking. Signs and symptoms include prolonged expiration, wheezing, diminished breath sounds, progressive dyspnea, and chronic cough. Chronic Obstructive Pulmonary Disease (COPD)
  • Relieves pulmonary vasoconstriction, thereby improving cardiac output and tissue perfusion
  • Indications:
    • 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% 
• Pharmacotherapy:
  • For chronic right heart failure or elevated RV filling pressures: diuretics (but monitor for volume depletion)
  • For primary pulmonary arterial hypertension Hypertension Hypertension, or high blood pressure, is a common disease that manifests as elevated systemic arterial pressures. Hypertension is most often asymptomatic and is found incidentally as part of a routine physical examination or during triage for an unrelated medical encounter. Hypertension or group 1 PH: 
    • Calcium channel blockers Calcium Channel Blockers Calcium channel blockers (CCBs) are a class of medications that inhibit voltage-dependent L-type calcium channels of cardiac and vascular smooth muscle cells. The inhibition of these channels produces vasodilation and myocardial depression. There are 2 major classes of CCBs: dihydropyridines and non-dihydropyridines. Class 4 Antiarrhythmic Drugs (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 Anticoagulants Anticoagulants are drugs that retard or interrupt the coagulation cascade. The primary classes of available anticoagulants include heparins, vitamin K-dependent antagonists (e.g., warfarin), direct thrombin inhibitors, and factor Xa inhibitors. Anticoagulants
• Surgical management:
  • COPD COPD Chronic obstructive pulmonary disease (COPD) is a lung disease characterized by progressive, largely irreversible airflow obstruction. The condition usually presents in middle-aged or elderly persons with a history of cigarette smoking. Signs and symptoms include prolonged expiration, wheezing, diminished breath sounds, progressive dyspnea, and chronic cough. Chronic Obstructive Pulmonary Disease (COPD) patients with hematocrit ≥ 65%: phlebotomy
  • Surgical embolectomy in massive pulmonary embolism Pulmonary Embolism Pulmonary embolism (PE) is a potentially fatal condition that occurs as a result of intraluminal obstruction of the main pulmonary artery or its branches. The causative factors include thrombi, air, amniotic fluid, and fat. In PE, gas exchange is impaired due to the decreased return of deoxygenated blood to the lungs. Pulmonary Embolism with acute cor pulmonale (if thrombolysis fails or is contraindicated)
  • Lung ± heart transplantation: for patients who failed therapy