Soru

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?