Pulmonary arterial hypertension due to antiphospholipid syndrome initially mimicking chronic thromboembolic pulmonary hypertension.

Pulmonary arterial hypertension (PAH) is the second most common lung complication in antiphospholipid syndrome (APS) patients. However, the concurrent development of APS-related nonthrombotic PAH is rarely reported. Lack of awareness for group 1 PAH in APS patient may contribute to underdiagnosis of this condition. Herein, we reviewed the case of a 56-year-old female who was diagnosed with PAH related to APS that mimicked chronic thromboembolic pulmonary hypertension (CTEPH). It is crucial to be aware of the possibility of a group 1 PAH diagnosis, even though patients have already been diagnosed with CTEPH. Furthermore, a multidisciplinary approach and serial follow-up right heart catheterization with echocardiography are important to make a timely diagnosis and provide optimal treatment for APS-related PAH in patients with CTEPH-like clinical features.