Chronic Thromboembolic Pulmonary Hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH), defined as precapillary pulmonary hypertension (PH) by right heart catheterization and imaging consistent with chronic thromboembolism, is a long-term complication of pulmonary embolism (PE). Pathobiological mechanisms involve pulmonary artery occlusion from organized thromboembolic material despite at least three months of uninterrupted therapeutic anticoagulation following acute PE and secondary microvasculopathy. Delay in diagnosis and management of CTEPH is associated with poor outcomes. High clinical suspicion, comprehensive assessment of residual dyspnea or exercise intolerance in the aftermath of PE and accurate interpretation of computed tomography pulmonary angiography (CTPA) are pivotal steps in the diagnosis. Ventilation–perfusion (V/Q) scan is the preferred initial radiologic screening tool as normal V/Q essentially rules out CTEPH. Any mismatched perfusion defect on the V/Q scan in the setting of PH or any finding compatible with chronic thromboembolism on CTPA should prompt referral to an expert CTEPH center. Once the diagnosis is verified, all eligible patients should be offered pulmonary thromboendarterectomy (PTE). Pulmonary vasodilators or balloon pulmonary angioplasty are safe and effective in inoperable or post-PTE persistent/recurrent CTEPH. During the course of their disease, a patient may receive a combination of treatments, at times consisting of all three strategies. Lifelong therapeutic anticoagulation is recommended for CTEPH.