Chronic Thromboembolic Disease: Epidemiology, Assessment with Invasive Cardiopulmonary Exercise Testing, and Options for Management

Recovery after acute pulmonary embolism occurs on a continuum from complete restoration of flow to persistent perfusion defects causing pulmonary hypertension. An under-recognized complication of pulmonary embolism is chronic thromboembolic disease (CTED), a condition characterized by abnormal perfusion but no resting pulmonary hypertension. These patients often present with dyspnea on exertion. In this review, we discuss the epidemiology of CTED and the physiologic reasons that dyspnea on exertion manifests, namely increased dead space ventilation and exercise-induced pulmonary hypertension. We present the protocol used for invasive cardiopulmonary exercise testing with right heart catheterization necessary to differentiate these two phenotypes of CTED and exclude other causes of dyspnea on exertion such as exercise-induced diastolic dysfunction. Finally, we discuss the potential management options for symptomatic CTED including pulmonary thromboendarterectomy and balloon pulmonary angioplasty.