Persistent breathlessness after pulmonary embolism: assessing operability
A 58-year-old woman had an unprovoked pulmonary embolism 14 months ago and has taken apixaban continuously since. She now reports progressive dyspnoea on minimal exertion, presyncope and reduced exercise tolerance. Examination shows raised jugular venous pressure, a loud pulmonary component of the second heart sound and a right ventricular heave. Echocardiography shows a dilated right ventricle, estimated right ventricular systolic pressure 62 mmHg and TAPSE 15 mm. Ventilation-perfusion scanning shows multiple mismatched segmental perfusion defects. NT-proBNP is 900 ng/L, and pulmonary function tests show mild restriction with DLCO 55% predicted. She has no history of left heart disease and no significant parenchymal disease on CT. She asks why she still feels breathless when she is taking anticoagulation.
1. What diagnosis should be considered, and what investigations are needed before treatment?
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Chronic thromboembolic pulmonary hypertension is the leading diagnosis: persistent dyspnoea beyond three months of anticoagulation, mismatched segmental defects on ventilation-perfusion scanning, right ventricular dysfunction and raised natriuretic peptide. She needs right heart catheterisation to confirm precapillary pulmonary hypertension-mean pulmonary arterial pressure above 20 mmHg, pulmonary artery wedge pressure 15 mmHg or less and elevated pulmonary vascular resistance-and computed tomographic pulmonary angiography to assess the location and extent of organised thrombus. Perform thrombophilia testing and screen for antiphospholipid syndrome, because this affects anticoagulation choice. Refer to a national pulmonary hypertension or chronic thromboembolic pulmonary hypertension centre for multidisciplinary operability assessment. Anticoagulation alone does not resolve organised fibrotic thrombus and does not exclude surgically accessible disease.
2. Why is continuing anticoagulation alone inadequate, and what are the treatment options?
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Anticoagulation prevents recurrent thrombosis but does not dissolve the organised fibrotic material that obstructs and remodels pulmonary arteries. If the disease is operable, pulmonary endarterectomy is the treatment of choice and can be curative; operability depends on thrombus accessibility, the degree of distal small-vessel disease and comorbidity, and is best judged by an experienced multidisciplinary team. If she is operable, refer for surgery rather than simply optimising medical therapy. If she is inoperable or has residual disease after surgery, options include riociguat, balloon pulmonary angioplasty in selected centres and continued lifelong anticoagulation. Supplemental oxygen and diuretics may help symptoms. Lung transplantation is reserved for refractory disease. Do not stop anticoagulation when starting pulmonary vasodilator therapy.
3. If she is judged inoperable, how would you manage her pulmonary hypertension and follow-up?
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Start riociguat, a soluble guanylate cyclase stimulator licensed for inoperable or persistent recurrent chronic thromboembolic pulmonary hypertension, after excluding contraindications such as recent stroke and uncontrolled hypotension. Consider balloon pulmonary angioplasty at an experienced centre, often in combination with medical therapy. Continue lifelong anticoagulation, with warfarin preferred if antiphospholipid syndrome is confirmed; direct oral anticoagulants are generally avoided in triple-positive antiphospholipid syndrome. Treat right heart failure with diuretics and give oxygen if hypoxaemic. Arrange regular review of functional class, six-minute walk distance, natriuretic peptide and echocardiography, and screen for complications of pulmonary hypertension. Reassess operability if local expertise changes, and discuss transplantation early if progressive right heart failure develops.