Antiphospholipid Syndrome in Chronic Thromboembolic Pulmonary Hypertension and Chronic Thromboembolic Pulmonary Disease without Pulmonary Hypertension: Prevalence and Clinical Impact in a Dutch Cohort.

Antiphospholipid syndrome (APS) is a prothrombotic autoimmune disorder associated with venous thromboembolism (VTE) and chronic thromboembolic pulmonary hypertension (CTEPH). Current guidelines recommend APS screening in CTEPH patients. The exact prevalence of APS in both CTEPH and chronic thromboembolic pulmonary disease (CTEPD) without pulmonary hypertension (PH) remains unclear. Although recently increasing attention has been directed toward treatment outcomes following pulmonary endarterectomy (PEA), other CTEPD without PH patients and those treated with alternative interventions, such as balloon pulmonary angioplasty or PH medication, remain insufficiently studied. This study aimed to assess the prevalence, lesion distribution, and outcomes of APS in CTEPH and CTEPD without PH. We retrospectively analyzed 259 patients diagnosed with CTEPH ( n = 233) or CTEPD without PH ( n = 26) at a tertiary care referral center in the Netherlands. Demographic, clinical, hemodynamic, laboratory, and follow-up data were collected from medical records. Lesion distribution in APS patients was related to literature. In 140 out of 259 patients, APS testing results could be retrieved. Among these, 112/140 (80%) had no APS, 19/140 (14%) tested positive without repeated confirmation or without APS clinical criteria, and 9/140 (6%) were classified as APS. Of the nine APS patients, four had a triple antibody profile. APS patients were relatively young (mean age 44 years), often had autoimmune comorbidities (3/9; 33%) and a history of recurrent VTE (6/9; 67%). All APS patients experienced mild thrombocytopenia post-PEA. Both proximal (5/9; 56%) and distal disease (6/9; 67%) were observed in APS. This study provides a real-world overview of CTEPH/CTEPD without PH patients with and without APS and contributes to the limited literature on this specific patient population.