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Difficulty: EasyCardiovascular System

An established clinic patient, who is 68 years old, presents for evaluation of bilateral leg swelling that has gradually worsened over the past 3 months. He additionally notes new-onset abdominal fullness and becoming breathless after walking short distances. The patient is oxygen-dependent due to a long-standing history of severe chronic obstructive pulmonary disease (COPD) and has previously smoked heavily for four decades. His temperature is 37.0°C (98.6°F), blood pressure is 135/85 mm Hg, and pulse is 88/min. Physical examination reveals markedly distended jugular veins, a palpable parasternal heave, and 3+ pitting edema of the lower extremities bilaterally. Cardiac auscultation reveals a holosystolic murmur at the left lower sternal border that increases in intensity with inspiration. Breath sounds are decreased bilaterally with a prolonged expiratory phase, but no crackles are heard. Which of the following is the most likely primary mechanism for this patient's current presentation?

  1. Elevated pulmonary arterial pressureAnswer
  2. B
    Decreased left ventricular ejection fraction
  3. C
    Abnormal retrograde flow across the mitral valve
  4. D
    Impaired right ventricular filling due to pericardial thickening
  5. E
    Obstruction of the superior vena cava

Answer

Elevated pulmonary arterial pressure
This patient's presentation is classic for cor pulmonale, which is defined as right ventricular hypertrophy and eventually right heart failure due to primary pulmonary disease. In patients with severe COPD, chronic alveolar hypoxia triggers hypoxic pulmonary vasoconstriction. Over time, this diffuse vasoconstriction leads to structural remodeling of the pulmonary vasculature and elevated pulmonary arterial pressure (pulmonary hypertension). The right ventricle must pump against this increased afterload, leading to right ventricular hypertrophy (evidenced by the palpable parasternal heave) and eventual right ventricular failure. This failure causes systemic venous congestion, manifesting as jugular venous distention, hepatic congestion (abdominal fullness), and significant peripheral edema. The dilation of the right ventricle also stretches the tricuspid valve annulus, causing functional tricuspid regurgitation (a holosystolic murmur at the left lower sternal border that increases in intensity during inspiration).

Step-by-Step Solution

1
Analyze the patient's history and risk factors.
The patient has severe, oxygen-dependent COPD.
Identifying the underlying chronic disease helps point toward its systemic complications.
2
Interpret the physical examination findings.
JVD, parasternal heave, lower extremity edema, and a murmur of tricuspid regurgitation (increases with inspiration) are present without pulmonary crackles.
These findings specifically indicate isolated right ventricular hypertrophy and right-sided heart failure.
3
Synthesize history and exam to determine the mechanism.
The combination of severe lung disease and right heart failure is diagnostic of cor pulmonale, which is driven by pulmonary hypertension.
Chronic hypoxia induces pulmonary vasoconstriction, leading to elevated pulmonary arterial pressure that overwhelms the right ventricle.

Key Concept

Cor Pulmonale
Estimated Time:1m 0s
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Topics

Cardiovascular System

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