A 56-year-old woman presents to the pulmonary hypertension clinic because of progressive exertional dyspnea and fatigue. Eighteen months ago, she was hospitalized for an unprovoked pulmonary embolism involving both main pulmonary arteries. She completed 6 months of anticoagulation but stopped treatment after losing insurance coverage. During the past 8 months, she has developed worsening exercise intolerance, intermittent exertional lightheadedness, and swelling of both ankles. She denies chest pain, fever, cough, or orthopnea. Her medical history also includes obesity and obstructive sleep apnea treated with nocturnal continuous positive airway pressure. Temperature is 36.8°C (98.2°F), blood pressure is 110/72 mm Hg, pulse is 92/min, and respiratory rate is 18/min. Oxygen saturation is 93% on room air. Physical examination demonstrates elevated jugular venous pressure, a right ventricular heave, and a loud pulmonic component of S2. There is a holosystolic murmur along the left lower sternal border that becomes louder with inspiration. The lungs are clear, and there is 1+ bilateral ankle edema. ECG demonstrates right-axis deviation and right ventricular hypertrophy. Echocardiography shows severe right ventricular dilation with reduced right ventricular systolic function, moderate tricuspid regurgitation, and an estimated pulmonary artery systolic pressure of 72 mm Hg. Left ventricular systolic function is normal.
Right-heart catheterization demonstrates:
Mean pulmonary artery pressure: 42 mm Hg
Pulmonary capillary wedge pressure: 10 mm Hg
Pulmonary vascular resistance: 7 Wood units
Cardiac index: 2.0 L/min/m²
Ventilation-perfusion scanning reveals multiple bilateral segmental perfusion defects with preserved ventilation. CT pulmonary angiography demonstrates organized thromboembolic material within the proximal pulmonary arteries that is technically accessible for surgical removal.
Which of the following is the most appropriate definitive treatment?
The correct answer is:
D) Pulmonary thromboendarterectomy
This patient has chronic thromboembolic pulmonary hypertension (CTEPH), a form of precapillary pulmonary hypertension caused by persistent organized thromboembolic material that obstructs the pulmonary arterial circulation. The diagnosis is supported by her history of prior pulmonary embolism, progressive exertional symptoms, right-sided heart failure findings, elevated pulmonary artery pressure and pulmonary vascular resistance, normal pulmonary capillary wedge pressure, and mismatched perfusion defects on ventilation-perfusion scanning.
The normal wedge pressure indicates that the pulmonary hypertension is not caused by elevated left-sided filling pressures. Instead, chronic mechanical obstruction and secondary remodeling of the pulmonary vasculature have increased right ventricular afterload. Over time, the right ventricle dilates and fails, producing elevated jugular venous pressure, tricuspid regurgitation, peripheral edema, and exertional presyncope.
Pulmonary thromboendarterectomy is the preferred definitive treatment when the thromboembolic lesions are surgically accessible and the patient is an acceptable operative candidate. The procedure removes organized thrombotic material from the pulmonary arteries, substantially reducing pulmonary vascular resistance and potentially curing the disease. All patients with CTEPH also require lifelong anticoagulation to prevent recurrent thrombosis, but anticoagulation alone does not remove established fibrotic obstruction.
A key Step 2 distinction is that CTEPH is one of the few potentially curable causes of pulmonary hypertension. Treatment choice depends largely on the location and operability of the obstructive lesions. Proximal surgically accessible disease is treated with thromboendarterectomy, whereas inoperable distal disease may be treated with balloon pulmonary angioplasty or targeted pulmonary vasodilator therapy.
Answer choice A: Balloon pulmonary angioplasty, is incorrect.
Balloon pulmonary angioplasty can improve hemodynamics and symptoms in patients with inoperable CTEPH, particularly when the obstructive disease is located in distal pulmonary arterial branches that cannot be reached surgically. It may also be considered when substantial pulmonary hypertension persists after surgery. This patient has proximal, technically operable disease, making pulmonary thromboendarterectomy the preferred definitive therapy.
Answer choice B: Lifelong anticoagulation alone, is incorrect.
Lifelong anticoagulation is necessary in all patients with CTEPH because recurrent thromboembolism can worsen pulmonary vascular obstruction. However, anticoagulation cannot dissolve or remove the mature organized fibrotic material already obstructing the pulmonary arteries. Using anticoagulation alone would leave the mechanical cause of the pulmonary hypertension untreated and allow progressive right ventricular failure.
Answer choice C: Lung transplantation, is incorrect.
Lung or heart-lung transplantation may be considered for selected patients with advanced pulmonary vascular disease that is refractory to all other treatments. However, it carries substantial perioperative risk and requires lifelong immunosuppression. This patient has a surgically correctable cause of pulmonary hypertension and should undergo thromboendarterectomy rather than transplantation.
Answer choice E: Riociguat therapy, is incorrect.
Riociguat stimulates soluble guanylate cyclase and can improve exercise capacity and pulmonary hemodynamics in patients with inoperable CTEPH or persistent pulmonary hypertension after thromboendarterectomy. It does not remove surgically accessible thromboembolic obstruction and should not replace potentially curative surgery in an operable patient.
Key Learning Point
Chronic thromboembolic pulmonary hypertension causes precapillary pulmonary hypertension due to persistent organized pulmonary arterial thrombi. Surgically accessible disease is treated with pulmonary thromboendarterectomy, whereas balloon pulmonary angioplasty or riociguat is reserved primarily for inoperable or residual disease.
