ABSTRACT Chronic thromboembolic pulmonary hypertension (CTEPH) is rare in adolescents, and evidence regarding balloon pulmonary angioplasty (BPA) in young patients with hereditary thrombophilia remains limited. A 16year‐old male was diagnosed with CTEPH and protein S deficiency, characterized by markedly low activity and antigen levels. Genetic analysis revealed a novel PROS1 frameshift variant (c.53del, p.Val18GlyfsTer69) predicted to cause loss of function. Despite anticoagulation and riociguat therapy, pulmonary hypertension persisted, and pulmonary angiography demonstrated predominantly peripheral organized thrombotic lesions. The patient underwent staged BPA at ages 16 and 17, with an additional session at 22. All procedures were completed without complications and were associated with sustained improvement in hemodynamics and exercise capacity during long‐term follow‐up. This case highlights the importance of considering hereditary thrombophilia in adolescent patients with CTEPH and suggests that staged BPA may be a safe and effective treatment option in selected patients with predominantly peripheral disease.
Fujii et al. (Wed,) studied this question.