Clinical and radiologic characteristics of chronic thromboembolic pulmonary hypertension patients without a history of acute venous thromboembolism

Background: Chronic thromboembolic pulmonary hypertension (CTEPH) is thought to result from incomplete resolution of vascular obstruction following acute pulmonary embolism. However, at least 25% of patients with CTEPH do not have a documented episode of acute venous thromboembolism (VTE). Objectives: We hypothesized that patients without a VTE in their past medical history have different clinical and radiologic characteristics compared with patients with CTEPH with previous acute VTE. Methods: Baseline data and the history of VTE were retrospectively retrieved from the charts of all patients with CTEPH included between 2014 and 2022 in the Amsterdam University Medical Center CTEPH registry. Computed tomography pulmonary angiography, right heart catheterization, and pulmonary function tests were performed in all patients. Subsegmental disease was defined by the presence of a contrast defect in the pulmonary arterial vessels after the first arterial branch division. Results: A total of 262 patients with CTEPH were included; 47 patients (18%) did not have previous acute VTE. Baseline radiologic assessment showed that subsegmental disease was more frequent in patients without previous VTE (n = 16/43; 35%, 95% CI: 22-49) than in patients with previous VTE (n = 27/214; 13% [95% CI: 9.0-18], OR: 2.6 [95% CI: 1.2-5.7]). The patients without previous VTE were less frequently assigned to pulmonary endarterectomy than patients with acute VTE (30% [95% CI: 18-44] vs 56% [95% CI: 49-62]; OR: 0.5 [95% CI: 0.2-0.9]). Comorbidities, pulmonary function, and hemodynamics were not different. Conclusion: Patients with CTEPH without previous VTE had more distally located disease on imaging than patients with CTEPH with previous VTE and were less often subjected to pulmonary endarterectomy.